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165 Cards in this Set

  • Front
  • Back
Lower extremity pain in three different patients (A, B, C), all members of the track team.
1. Describe the findings in Patient A.
2. What is the most likely diagnosis?
3. Describe the findings in Patients B and C.
4. Provide the most likely diagnosis for Patients B and C.
Skeletal System: Stress Fractures
1. Increased activity in a linear pattern along the posterior and medial aspect of both mid-tibias.
2. Shin splints.
3. Patient B: focal ovoid activity posteromedial right tibia at the junction of the proximal two thirds and distal one third. Patient C: focal fusiform activity posteromedially in the right proximal tibia and linear activity along the posteromedial left tibia proximally and more prominently distally.
4. Patient B: stress fracture. Patient C: stress fracture and shin splints.
1. Describe the bone scan abnormality.
2. Provide descriptive terms that could be used to describe the pattern in the tibia.
3. Provide the differential diagnosis.
4. The patient may experience clinical symptoms related to another organ system. Discuss the mechanism.
Skeletal System: Paget's Disease
1. Abnormal highly increased uptake in the entire left femur, which appears bowed and widened, and the distal third of the left tibia, which tapers proximally.
2. A sharp leading edge, referred to as "flame-shaped" or "blade of grass," may be demonstrated on the lytic phase on radiograph and on bone scintigraphy.
3. Paget's disease, fibrous dysplasia, chronic osteomyelitis, primary bone tumors, but principally osteosarcoma.
4. High-output congestive heart failure may occur. Once believed to be the result of arteriovenous shunting within the bone lesion, now hyperemia and increased blood flow through the lesion, and not shunting, are likely causes.
Two patients (A and B) referred with chest wall pain.
1. Describe the bone scan findings.
2. Is there a pattern to the abnormalities?
3. What causes should be considered?
4. Based on the scan findings, provide the most likely diagnoses.
Skeletal System: Rib Fractures and Sternotomy
1. Patient A: focal increased uptake in multiple ribs posterolaterally and at the costovertebral junctions. Patient B: increased vertical linear uptake in the sternum from the manubrium to the xiphoid.
2. The uptake in adjacent ribs (Patient A) and the vertical uptake in the sternum both have a geometric and characteristic pattern.
3. Trauma or surgery.
4. Patient A: multiple rib fractures. Patient B: median sternotomy for coronary artery bypass grafting (CABG) 6 months ago.
A 60-year-old patient with diabetes with cellulitis of the distal foot, referred to rule out osteomyelitis of the left great toe.
1. Describe the physiology of each of the three phases.
2. Describe the scintigraphic findings in this case.
3. Interpret the study.
4. What is the sensitivity and specificity of the three-phase bone scan for osteomyelitis?
Skeletal System: Pedal Osteomyelitis Three-Phase Positive
1. First phase: arterial blood flow to the bone. Second phase: blood pool or interstitial space distribution immediately following the flow. Third phase: bone uptake phase at 3 hours after injection. All three phases are typically focally increased with osteomyelitis. With cellulitis, only the first two phases are positive.
2. Increased flow, blood pool, and delayed uptake to the left first digit distal phalanx.
3. Consistent with osteomyelitis of the digit. Recent fracture must be excluded with radiography.
4. Sensitivity and specificity of approximately 95% if the radiograph is normal or has only suggestive changes of osteomyelitis.
Patient referred for bone scan because of right-sided chest pain.
1. Describe scintigraphic findings.
2. Provide a differential diagnosis.
3. What other examinations may be helpful in this setting?
4. What is the likely reason for ordering the bone scan?
Skeletal System: Abnormal Breast Uptake
1. Nonuniform abnormal soft tissue uptake exists in the soft
tissue overlying the chest, likely in the right breast.
2. Breast cancer, aseptic or septic mastitis, primary skin dis
ease, such as psoriasis, vascular or lymphatic obstruction,
radiation therapy.
3. Breast examination, mammography, and possible biopsy.
4. To determine whether breast cancer bone metastases are
Pain in the left shoulder; rule out metastasis.
1. Describe the findings.
2. Name three general processes that could account for the findings.
3. What is the likely primary tumor for which metastases are being excluded?
4. What is the most likely diagnosis?
Skeletal System: Lymphedema
1. The soft tissues of the left arm are enlarged and show abnormal increased soft tissue activity; the left anterior ribs are uniformly more intense than the right.
2. Venous or lymphatic obstruction, soft tissue neoplasm, soft tissue injury.
3. Breast cancer.
4. Lymphedema secondary to axillary lymph node dissection and left mastectomy.
1. Describe the bone scan findings.
2. Provide the general classification for this finding and the likely diagnosis.
3. Name other conditions that fall into the same spectrum of abnormalities.
4. Are increased risks associated with this condition?
Skeletal System: Bone Abnormalities of Renal Position
1. The right kidney is not seen in the renal fossa. Nonuniform activity is noted in the right sacroiliac region, which extends beyond the expected superior margin of the bone.
2. Congenital renal anomaly, pelvic kidney.
3. Anomalies of number (supernumerary kidney), position (malrotation), or fusion (horseshoe).
4. Yes. Ureteropelvic junction obstruction, vesicoureteral reflux, decreased function, increased risk of trauma. Urine stasis resulting from distorted anatomy increases the risk of stone formation.
A 67-year-old man has an elevated serum prostate-specific antigen (PSA) level.
1. Describe the findings on this bone scan and interpret the study.
2. What would you predict the serum PSA level to be?
3. Which metastatic cancers have predominantly lytic lesions in bone and thus lower sensitivity for their detection by bone scanning?
4. If a patient with prostate cancer has a significantly elevated serum PSA level postoperatively but negative bone scan findings, what other imaging options are indicated?
Skeletal System: Metastatic Prostate Cancer
1. Abnormal focal uptake throughout the axial and appendicular skeleton strongly suggestive of metastatic disease. The many distal appendicular lesions usually are seen with latestage
2. Considerably greater than 20 ng/ml. The prevalence of bone scan—evident metastases is less than 1% below this level.
3. Multiple myeloma, followed by thyroid cancer, renal cell carcinoma, lymphoma.
4. CT and MRI have a poor sensitivity for detection of prostate cancer soft tissue/nodal metastases, less than 20%. An In ProstaScint study is indicated.
Patient with breast cancer. The serial bone scans are dated as follows: A, 4/97; B, 5/99; C, 8/99; D, 4/00.
1. Describe the bone scan findings and changes over time. The 4/97 scan was completely normal.
2. What is the likelihood of tumor with new focal uptake in a single rib in a patient with known cancer? What is the likelihood with new solitary spine lesions?
3. What are different general scan patterns in metastatic disease?
4. What is the cause of the relatively cold defect in the left hemithorax?
Skeletal System: Breast Cancer
1. B, New increased uptake at T7 suspicious for tumor; C,
multiple new lesions in the thoracic spine, fourth right rib,
left sacrum, and single focus in the anterior skull all
strongly suspicious for tumor; D, continued progression
with new tumor sites in the spine and left sacrum and new
focal uptake in left iliac crest, right intertrochanteric
femur, and right acetabulum.
2. Less than 20%; greater than 40%.
3. Solitary focal lesion, multiple focal lesions, diffuse involve
ment (superscan), cold lesion, soft tissue uptake, flare
4. Breast prosthesis.
A 62-year-old patient has right-sided chest discomfort and shortness of breath. A, Posteroanterior chest radiograph;
B, perfusion; C, ventilation.
1. Describe the ventilation-perfusion image findings.
2. Interpret the study. Give your reasoning.
3. What is the likelihood of pulmonary embolus in this patient?
4. What are the most common chest x-ray findings in patients with pulmonary emboli?
Pulmonary System: High Probability of
Pulmonary Embolus
1. Perfusion is decreased in the right lower lobe except for the
superior segment. Ventilation is truncated in the right
lower lobe consistent with subpulmonic effusion.
2. High probability for pulmonary embolus. Mismatch
between perfusion and ventilation is evident in the basal
segments. The perfusion defect is considerably larger than
the effusion on the radiograph.
3. Greater than 80%.
4. Most common: normal. Next most common: atelectasis;
these also are the most common chest x-ray findings in
patients determined by angiography not to have emboli.
A chest radiograph (A), posterior 133Xe ventilation (B), and eight-view perfusion study (C) were performed for short
ness of breath.
1. Describe the findings on the ventilation study.
2. Describe the findings on the perfusion study.
3. Provide an interpretation regarding the presence or absence of pulmonary embolism.
4. What term could be applied to this perfusion pattern?
Pulmonary System: Ventilation-Perfusion—
Stripe Sign, Emphysema
1. Decreased upper lobe ventilation is seen on the single
breath with air trapping in both upper lobes and the right
lower lobe on washout images.
2. Decreased perfusion to the majority of both lungs, with
preserved perfusion in the subpleural lung, most evident at
the lung bases and medial aspect of both upper lobes.
3. Low probability.
4. Stripe sign.
A young female patient presents at the emergency department with chest pain. Chest radiographs (A, B), perfusion
scan (C), and ventilation study (D) are shown.
1. Describe the findings on the chest radiograph.
2. Describe the perfusion and ventilation scans.
3. Categorize the study regarding the presence or absence of pulmonary embolism using PIOPED criteria.
4. What is the most common finding on chest radiographs with thromboembolism?
Pulmonary System: Hampton's Hump—
Intermediate Probability
1. Posteroanterior and lateral chest radiographs demonstrate
a pleural-based opacity in the lateral right lung base.
2. A single wedged-shaped, pleural-based defect in the same
location as the radiographic abnormality, probably the
anterobasal segment of the right lower lobe. Normal 133Xe
ventilation study.
3. Intermediate probability for pulmonary embolism.
4. Chest x-ray findings in pulmonary embolus without
infarction are uncommon. When present, they are usually
associated with a large, central embolus. Discoid atelectasis
is the next most common finding.
A 39-year-old woman had acute upper abdominal pain. Cholescintigraphy was requested.
1. What patient preparation is required before cholescintigraphy?
2. Which hepatobiliary radiopharmaceuticals are available in the United States?
3. What are the radiopharmaceuticals mechanisms of uptake and their differences?
4. Has acute cholecystitis been ruled out? With what degree of certainty?
Hepatobiliary System: Cholescintigraphy—
Normal Study
1. No oral intake for 3 to 4 hours before radiopharmaceutical
2. 99mTc disofenin (DISIDA), Hepatolite. 99mTc mebrofenin
(BrIDA), Choletec.
3. Both are iminodiacetic acid (IDA) analogues, extracted and
excreted by hepatocytes into the biliary system. Mebrofenin
has higher hepatocyte extraction (98% vs. 88%).
4. Yes. Acute cholecystitis (cystic duct obstruction) is ruled
out with a high degree of certainty. The false-negative rate
is 1% to 5%.
A 35-year-old man has been comatose for 2 weeks since a recent severe head injury. The electroencephalogram (EEG)
is flat and he is being considered as an organ donor.
1. If the EEG is a flat line, why is another study indicated?
2. What are the clinical findings of brain death?
3. List two different types of radiopharmaceuticals with different mechanisms that could be used for this study.
4. What are the scintigraphic findings and the diagnosis?
Central Nervous System: Brain Death
1. An isoelectric flat EEG can be caused by barbiturates,
depressive drugs, or hypothermia.
2. Deep coma, no brain stem reflexes or spontaneous respira
tion, exclusion of reversible causes, and the cause of the
brain dysfunction must be diagnosed.
3. 99mTc diethylenetriaminepentaacetic acid (DTPA) or
99mTc pertechnetate can be used as a brain flow study
(radionuclide angiogram). However, 99mTc HM-PAO and
99mTc ethyl-cysteinate dimer (ECD) have the advantage of
irreversible cellular binding on the first pass, allowing for
delayed images.
4. No blood flow to the cerebral cortex. Brain blood flow study
consistent with brain death. This is a 99mTc DTPA study.
99mTc HM-PAO would show salivary uptake. With normal
brain perfusion, cerebral cortical activity would be seen.
A 55-year-old man with hypercalcemia has an elevated serum PTH level. Images are taken at 5 minutes and at 1 and
2 hours.
1. Which radiopharmaceutical is being used, and what is the rationale for this technique?
2. What is the diagnosis?
3. What is the accuracy of this study?
4. What is the most common cause for a false-positive study result?
Endocrine System: Hyperparathyroidism
1. 99mTc sestamibi (MIBI) is taken up by the thyroid and para
thyroid tissue, but washes out more rapidly from the thyroid.
2. Parathyroid adenoma in the region of the left lower lobe of
the thyroid.
3. Greater than 90% predictive value for preoperative local
ization of parathyroid adenoma; lower test accuracy for
hyperplasia and small tumors.
4. Thyroid follicular adenoma.
A patient has elevated serum calcium and parathyroid hormone levels and normal findings on neck examination.
1. What other protocol in addition to dual-phase (early and delayed) 99mTc sestamibi imaging can be used to evaluate
for parathyroid disease?
2. Describe how that procedure is performed.
3. Describe the findings. Left: 99mTc sestamibi; middle: 123I; right: subtraction.
4. List the differential diagnosis and the most likely diagnosis.
Endocrine System: Parathyroid Adenoma
1. Dual-isotope imaging with subtraction, in the past using
201Tl and 99mTc pertechnetate, and more recently using
123I and 99raTc sestamibi (MIBI).
2. 123I by mouth. After a delay of 2 to 3 hours, an anterior
123I thyroid scan is obtained. Without moving the patient,
an image is obtained after intravenous injection of 99mTc
MIBI. The I23I image is computer subtracted from the
99mTc MIBI image.
3. The I23I thyroid scan appears normal, although the left
lobe extends more inferiorly (middle). The MIBI image
(left) shows an asymmetrical bulbous configuration in the
region of the right lower pole of the thyroid. Subtraction
demonstrates focal radiotracer compatible with parathy
roid adenoma at the lower pole of the right thyroid (right).
4. Parathyroid, thyroid adenoma, parathyroid, thyroid carci
noma, metastatic carcinoma.
A 13-year-old girl adolescent with sickle cell disease, low-grade fever, arm, leg, and back pain was referred for a bone
scan (A). The scan was repeated 1 year later; the patient now has arm and back pain (B).
1. Describe the scintigraphic bone and soft tissue findings.
2. What is the likely diagnosis?
3. What other nuclear medicine study can detect sickle infarcts?
4. How can osteomyelitis be differentiated from bone infarct?
Skeletal System: Sickle Cell Disease
1. A, Abnormal increased uptake in the proximal right
humerus, left distal femur, multiple sites in the thoracic
and lumbar spine. B, Uptake in the right ulna and left pos
terior ninth rib. Subtle soft tissue uptake is present in the
region of the spleen.
2. Sickle cell crises with infarcts.
3. 99mTc sulfur colloid bone marrow scan.
4. Combined 99mTc bone scan and marrow scan early in the
acute crisis.
A 65-year-old man had had intermittent rectal bleeding for 2 days.
1. Describe the scintigraphic findings during this 90-minute study.
2. What is the purpose of the oblique/lateral pelvic view (last image) in this case?
3. What is your interpretation of the study?
4. What are the criteria for diagnosing and localizing a bleeding site?
Gastrointestinal System: Rectal Bleeding
1. Abnormal activity accumulates early in the lower midline
pelvis. The appearance is changing over time and seems to
decrease and then increase again.
2. To differentiate activity in the rectum from bladder and
penis, in this patient the activity is seen in the rectum.
3. Positive for gastrointestinal bleeding is not the answer.
Localization is critical. The 90-minute lateral view con
firms that this is rectal bleeding.
4. New activity, increases in amount over time, and moves
A 53-year-old woman was referred for recent enlargement of the right lower lobe of a known multinodular thyroid
gland and a suppressed TSH level. The patient had radiation therapy for acne as a teenager.
1. Describe the scintigraphic findings of this 99mTc pertechnetate scan {left to right: anterior, left anterior oblique, right
anterior oblique).
2. Give the likely diagnosis.
3. What are the therapeutic options?
4. What is the likelihood of thyroid cancer in this patient?
Endocrine System: Toxic Nodular Goiter and
Thyroid Cancer
1. Multiple hot and cold regions throughout both lobes with
apparent suppression of nonnodular gland.
2. Multinodular toxic goiter.
3. Biopsy. If benign, then 131I therapy or surgeiy for multi
nodular goiter.
4. The likelihood of thyroid cancer is less than 5% in
patients with a multinodular goiter. A dominant nodule
increases the suspicion for cancer. A history of radiation
therapy to the head and neck significantly increases this
patient's risk of thyroid cancer.
A 55-year-old woman is referred for a thyroid scan to evaluate a palpable thyroid nodule. Left to right views are ante
rior, right anterior oblique, and left anterior oblique.
1. What are the two radiopharmaceuticals used for thyroid scintigraphy, their photopeaks, and physical half-lives?
2. What is the likelihood of thyroid cancer in this patient?
3. What would you recommend as the next diagnostic or therapeutic procedure?
4. What imaging method is used here? What is its image resolution?
Endocrine System: Cold Thyroid Nodule
1. Intravenous 99mTc pertechnetate, 140 keV, 6 hours; oral
sodium 123I, 159 keV, 8 hours.
2. A single cold nodule has a 15% to 20% chance of
3. Aspiration needle biopsy.
4. Pinhole collimator. 4 to 6 mm.
A 2-year-old child has an abdominal mass.
1. Describe the scintigraphic bone scan findings.
2. Name a likely organ of origin.
3. What is the most likely diagnosis?
4. Is the current examination adequate for staging of the patient's illness?
Skeletal System: Neuroblastoma
1. Large region of nonuniform abnormal soft tissue uptake
predominantly in the left side of the abdomen that appears to cross the midline. Its boundaries cannot be distinguished from the two kidneys.
2. Adrenal gland.
3. Neuroblastoma.
4. No.
1. Describe the abnormal bone scan findings in scan A.
2. Provide a differential diagnosis.
3. Describe the findings in scan B, a delayed spot image.
4. Explain the change and provide the most likely diagnosis.
Skeletal System: Extrarenal Pelvis and Mobile Solitary Right Kidney
1. Solitary right kidney with a prominent renal pelvis. Incidental uptake at antecubital injection site.
2. Ureteropelvic junction obstruction or obstruction secondary to other processes, extrarenal pelvis.
3. The renal pelvis has drained and the kidney is now seen inferomedial to its prior location.
4. Image B was taken with the patient erect, leading to gravity drainage of an extrarenal pelvis. The kidney is mobile (ptotic).
Because of a "jaw problem", a bone scan (A) and a bone scan and CT-30 reconstruction (B) were obtained in two children.
1. Describe the bone scan findings.
2. What additional information would be helpful?
3. Provide a short differential diagnosis.
4. The mother says there is no known disease in the child (B) or family. What is the most likely diagnosis?
Skeletal System: Fibrous Dysplasia
1. A shows increased uptake in the entire mandible. B shows intense increased uptake in the mandible and maxilla, which appear deformed and overgrown.
2. Check the rest of the bone scan for other sites; obtain a history of known underlying or familial disease.
3. Fibrous dysplasia, cherubism.
4. Fibrous dysplasia.
1. Describe the findings in patient A.
2. Describe the findings in patient B.
3. Provide the most likely reason for this appearance.
4. Explain the mechanism for the scan appearance.
Skeletal System: Radiopharmaceutical
Infiltration, Scatter, and Lymph Node Uptake
1. Intense uniform activity in the soft tissues of the distal left
forearm and focal activity in the left axilla, nonuniform
activity in the left lateral buttock.
2. Intense activity in the left foot, linear activity indicating
lymphatic channels, and left inguinal lymph node. Scatter
is seen lateral to the left foot.
3. Partial extravasation of the bone radiotracer at the site of
intravenous injection in the left forearm.
4. Demonstration of an axillary lymph node because of lym
phatic clearance of the extravasated radiopharmaceutical.
Scatter from the arm infiltrate results in apparent (but
unreal) increased activity in the buttock.
Two patients have low back pain. Patient A has blood pool (left) and delayed images (right) available; for Patient B,
only delayed images are shown.
1. Describe the bone scan abnormalities.
2. Provide the differential diagnoses.
3. List three other sites that are at increased risk for the same process.
4. What is the most likely underlying process in both patients?
Skeletal System: Sacral Insufficiency Fracture
1. Patient A has increased blood pooling and delayed uptake
bilaterally in the region of the sacroiliac joints and across
the sacrum (H pattern). The bone scan for Patient B
demonstrates abnormal increased radiotracer in a curvilin
ear linear pattern across the lower sacrum.
2. Both of these are diagnostic of sacral insufficiency fractures.
3. Proximal femur, wrist, and proximal humerus.
4. Osteoporosis.
An elderly woman with a history of prior right hip fracture comes to the emergency department because of pelvic pain and inability to walk. A bone scan was obtained.
1. Describe the scintigraphic findings.
2. What is the differential diagnosis?
3. What is the most likely diagnosis?
4. Name three medical conditions that predispose patients to this underlying disease process.
Skeletal System: Multiple Insufficiency Fractures
1. Multiple focal areas of increased radiotracer uptake are noted in several ribs, multiple sites in both pubic rami, lower sternum, and multiple vertebra.
2. Multifocal involvement by benign or malignant tumor, multifocal osteomyelitis, fractures.
3. Multiple insufficiency fractures. Degenerative change is present in the right shoulder and postoperative change related to previous right hip orthopedic fixation.
4. Hypercortisolism, hyperparathyroidism, hyperthyroidism.
A 55-year-old man with exertional chest pain had a stress single photon emission computed tomography (SPECT)
myocardial perfusion study.
1. Describe the perfusion abnormalities and give your interpretation.
2. Name the culprit vessel or vessels.
3. List any ancillary scan findings.
4. List clinical findings related to the stress test relevant to interpretation of the scan.
Cardiovascular System: Left Anterior
Descending Artery Ischemia
1. Severe decreased perfusion in the majority of the anterior
wall, apex, and septum, which normalizes on the rest
image indicating extensive severe ischemia.
2. Left anterior descending (LAD) coronary artery.
3. Transient cavity dilation.
4. Ventricular tachyarrhythmias, angina-related ST-segment
abnormalities, decrease in systolic blood pressure, level of
exercise achieved.
A 60-year-old man with a history of remote myocardial infarct and CABG surgery. Echocardiography results were normal.
1. Describe the SPECT findings.
2. Provide the differential diagnosis.
3. Give the most likely diagnosis.
4. Explain the discrepancy between the cardiac echocardiogram and the SPECT scan.
Cardiovascular System: Apical Infarct
1. Fixed stress (str) and rest (rst) severe apical lateral perfusion
defect of small size. Heart and cavity size appear normal.
2. Myocardial infarction, apical thinning, attenuation.
3. Small apical lateral scar.
4. Technical factors, operator error, interpretation error.
Dual-isotope stress SPECT myocardial perfusion study.
1. Describe the various imaging protocols used for 99mTc myocardial perfusion tracers.
2. What radionuclides are used for a dual-isotope study?
3. List the advantages of the dual-isotope technique compared with a single-isotope study.
4. Describe the SPECT findings and interpret the study.
Cardiovascular System: Dual-Isotope Study—Mild Inferior Ischemia
1. Two-day stress/rest; same-day rest/stress; same-day stress/rest.
2. Tl chloride for rest; Tc sestamibi or tetrofosmin for stress.
3. The dual-isotope technique requires a shorter time to complete the examination. Wall-motion assessment and gated SPECT are available from Tc perfusion study. Tl can be used to assess viability.
4. Mild decreased inferior wall perfusion at stress with mild improvement at rest. Mild inferior wall ischemia (right coronary artery). (Liver activity on the stress images suggests pharmacological stress. Normal biliary clearance is present on projection images).
A 50-year-old woman has atypical chest pain. The exercise treadmill test result with adequate exercise was interpreted as negative. SPECT perfusion images (A, gated short-axis; B, vertical long-axis; C, SPECT wall thickening; D, sequential raw data projection acquisition images) are provided.
1. Describe the SPECT myocardial perfusion image findings and gated SPECT.
2. What information is available from the raw data sequential projection images?
3. What is the most likely diagnosis?
4. List the advantages of electrocardiograph-synchronization (gating) to SPECT.
Cardiovascular System: Breast Attenuation, Wall Thickening
1. Mild fixed anteroseptal hypoperfusion that demonstrates uniform brightening on gated SPECT, indicating normal myocardial wall thickening on gated images.
2. Apparent decreased radiotracer in the upper portions of the heart is most obvious on the left anterior oblique and lateral frames. No obvious patient motion.
3. Normal perfusion study with normal wall thickening and breast attenuation.
4. Assessment of regional wall motion/wall thickening and left ventricular ejection fraction (LVEF).
After the rest scan the patient said he could not stay for the stress study but would reschedule. However, the patient
came to the emergency department the next morning with chest pain. 99mTc sestamibi was injected during the pain,
and the images were labeled "stress."
1. Describe the SPECT findings.
2. Name the most likely culprit coronary artery or arteries.
3. Which radiopharmaceuticals are preferred in this setting?
4. Provide the reason for your choice of radionuclide.
Cardiovascular System: Emergency
Department Chest Pain
1. Moderately severe perfusion defect of the entire anterior
wall extending to the apex that partially reverses on rest
images, severe perfusion defect of the defect involving the
lateral and inferolateral wall that partially reverses.
2. LAD and left circumflex coronary arteries or left main
coronary artery.
3. 99nlTc sestamibi or 99mTc tetrofosmin.
4. The exact image timing of 99mTc-labeled agents is not cru
cial because no significant redistribution occur. In an
emergency setting, matters of patient management and
logistics may take priority over immediate scanning.
Scans for two patients are provided. A, Stress and 4-hour delayed planar thallium scan. B, Poststress SPECT anterior
raw data projection image. Stress/rest SPECT showed single-vessel ischemia.
1. Describe the planar scintigraphic findings in patient A and the abnormal finding in patient B.
2. What other information is necessary for interpretation of these examinations?
3. Name ancillary findings of CAD other than perfusion defects that are relevant in interpreting myocardial perfusion
4. What is the most appropriate diagnosis in patients A and B?
Cardiovascular: Planar Thallium with
Increased Lung Activity
1. A, Both ventricles are dilated with prominent right ven
tricular uptake. No evidence of ischemia or scar. Increased
lung activity on the stress images.
2. The level of exercise achieved. At a low level of stress, the
scan can provide false-negative indication of CAD.
3. Poststress lung uptake and transient ischemic dilation.
4. A, Dilated cardiomyopathy with right ventricular hyper
trophy. B, Multivessel CAD.
A 45-year-old man has dyspnea on exertion. Cardiac catheterization found no coronary disease. Images at end-diastole
(left) and end-systole (right) are shown.
1. Name the radiopharmaceutical, the examination being performed, and describe the findings.
2. Which view is shown, and why was it selected to calculate LVEF? Name other views often obtained.
3. List the terms used to describe myocardial wall motion.
4. Provide a classification for cardiomyopathies.
Cardiovascular System: Cardiomyopathy on
Equilibrium-Gated Blood Pool
Ventriculography or Multigated Acquisition
1. 99mTc-labeled erythrocytes. Equilibrium-gated blood pool
ventriculography (RVG) or MUGA (multigated acquisi
tion). Frames at end-diastole and end-systole show globally
decreased wall motion. Visual estimate shows very
decreased LVEE
2. The left anterior oblique view provides the best septal sep
aration of the two ventricles. Occasionally anterior and left
lateral posterior oblique views also are obtained.
3. Global or regional—akinesis, hypokinesis, dyskinesis,
4. Classification according to the functional status of the ven
tricle: restrictive, dilated, or hypertrophic; or according to
cause: alcoholic, infectious, metabolic, toxic, druginduced,
or ischemia/CAD, idiopathic.
A 45-year-old woman was referred for a ventilation-perfusion study. The perfusion scan only is shown.
1. Describe the abnormal scintigraphic findings.
2. What is the most likely cause for the findings?
3. What is the radiation dose to the patient from a perfusion study? From a 133Xe ventilation study?
4. Given the longer physical half-life and larger administered dose of 133Xe, compared with 99mTc macro-aggregated
albumin (MAA), explain the lower resulting radiation dose to the lungs.
Pulmonary System: "Hot Spots" on Lung Scan
1. Multiple "hot spots" are present in the upper and lower
lobes, predominately in the right lung field.
2. Radioactive emboli as a result of poor technique caused by
drawing back blood into the syringe containing the 99mTc
MAA before injection of the radiotracer, causing clumping.
3. The lungs, the target organs, receive approximately 1 rad/5
mCi from 99mTc MAA. Approximately 0.2 rads to the
lung from a 20-mCi xenon study.
4. The biological half-life is brief. The patient breathes 133Xe
gas to equilibrium, then expels it into a trap. Only 133Xe
absorbed as a result of fat solubility has any appreciable
biological half-life.
Two patients with the same disease (A and B) had 67Ga scintigraphy.
1. Describe the lung patterns seen on the 67Ga lung scans.
2. What is the finding on the head and neck scan?
3. Match the lung scan with the head and neck scan.
4. What is the disease, and how is 67Ga scintigraphy used in these patients?
Infection and Inflammation: Sarcoidosis
1. Patient A, "lambda sign" (hilar and paratracheal nodal
uptake); patient B, diffuse pulmonary uptake.
2. Classic "panda" sign.
3. Either A or B. The panda sign can be seen at any stage of
4. Sarcoidosis. 67Ga scintigraphy is used to confirm the clini
cal diagnosis and to differentiate active alveolitis from
inactive fibrosis.
A 57-year-old man has had abdominal discomfort and fever for 3 weeks.
1. Describe the findings on this 67Ga study and give a likely diagnosis.
2. What is the mechanism of 67Ga uptake in infection/inflammation?
3. List the photopeaks of 67Ga. List the ones used for imaging. What collimator should be used to acquire the study?
4. What is the recommended administered dose of 67Ga, its half-life, and imaging times?
Infection and Inflammation: Intraabdominal
1. Very increased uptake in the right lower quadrant strongly
suggests an intraabdominal abscess. Tumor cannot be
2. Increased vascular permeability, bacterial uptake, and
binding to leukocytes play a role; however, binding to
lactoferrin of degranulated neutrophils at the site of infec
tion is probably the primary mechanism.
3. Photopeaks occur at 91 to 93, 185, 300, and 394 keV. The
lower three photopeaks are used for imaging. A mediumenergy
collimator should be used.
4. The recommended adult dose of 67Ga is 5 mCi; the halflife
is 78 hours. Imaging at 48 hours is routine. However,
if an abscess is suspected, imaging at 6 to 24 hours may
provide an early diagnosis.
A 9-year-old patient had back pain and fever for 4 weeks. Bone (A), gallium-67 whole-body (B) and abdominal spot
views (C) are shown.
1. Describe the scintigraphic findings on the bone and gallium scans.
2. When both tests are ordered at the same time, which should be performed first?
3. Provide the differential diagnosis and the most likely diagnosis.
4. Based on the available information, characterize the stage of disease.
Oncology: Bone/Gallium—Stage IV Hodgkin's
1. The bone scan shows mild increased uptake at L3. The
67Ga scan shows abnormal uptake in the L3 vertebral body,
as well as the neck bilaterally (right side greater than the left
side), mediastinum, right paratracheal regions, posterior
thorax, and right lung base; and multifocal uptake in the
liver. The lower-intensity camera setting optimizes liver
visualization (C).
2. Bone scan.
3. Hodgkin's disease, tuberculosis, or atypical mycobacteria;
Hodgkin's disease is likely.
4. Stage IV.
A 32-year-old man has non-Hodgkin's lymphoma. A shows the 67Ga study at initial staging, and B was performed after
a full course of chemotherapy. CT showed a residual chest mass after chemotherapy.
1. What is the adult dose of 67Ga for tumor evaluation? When is imaging performed?
2. Compare the accuracy of 67Ga and CT for initial staging and evaluating response to therapy.
3. Describe the findings of the two studies and interpret them.
4. How can the problem of bowel activity be minimized on 67Ga scans?
Oncology: 67Ga—Non-Hodgkin's Lymphoma
Before and After Therapy
1. The adult dose is 10 mCi, which is twice the dose used for
inflammatory and infectious evaluation. Imaging typically
is performed 48 to 72 hours after injection.
2. CT scanning provides better sensitivity for initial staging.
67Ga scanning is superior to CT in evaluation of the effec
tiveness of therapy and determination of whether residual
masses after therapy represent residual tumor or merely
necrosis and fibrosis.
3. A, A large mass in the anterior mediastinum extends to
the supraclavicular regions. Considerable colonic/rectal
activity is present. Because of the latter activity, tumor
cannot be excluded in the mid-pelvis to the lower pelvis.
B, Complete response to therapy has occurred. The resid
ual chest mass on CT is caused by necrosis and fibrosis,
not tumor.
4. Laxatives may be given, and imaging may be delayed as
needed at 4 to 7 days after injection.
A 67-year-old man has a 2.5-cm left upper lobe lung lesion detected on chest radiographs and confirmed with CT (A).
18F fluorodeoxyglucose positron emission tomography (FDG-PET) scan is shown (B).
1. What percentage of all newly discovered pulmonary nodules are malignant?
2. What percentage of single pulmonary nodules are indeterminate in etiology after chest radiography and CT exami
nation? What percentage ultimately are benign?
3. What is the likelihood of lung cancer in this case?
4. What are causes for false-negative/false-positive I8F FDG-PET studies?
Oncology: FDG-PET—Single Pulmonary Notes
1. Only 20% to 30% are malignant overall. However, the
incidence is as high as 50% in smokers.
2. By radiographic/CT criteria, 30% to 40% are indetermi
nate; 50% percent of these are benign.
3. High.
4. False-negative findings are uncommon and usually are the
result of small lesion size (<1.0 cm), bronchoalveolar car
cinoma, and carcinoid tumors. False-positive findings can
be caused by benign tumor, and inflammatory or infec
tious disease, e.g., histoplasmosis, tuberculosis. Typically
inflammatory lesions have less uptake than malignant
tumors, but overlap exists.
A 38-year-old man had a diagnosis of grade I-II astrocytoma and was treated 11 years ago. He has had a recent onset
of seizures. MRI showed no definite change from the many prior studies (B).
1. What FDG-PET scan findings are expected with a low-grade glioma?
2. What is the finding on this FDG-PET scan (A)?
3. Interpret this study.
4. Would 99mTc HM-PAO show a similar appearance?
Primary Brain Tumor
1. Low-grade gliomas typically have poor or no uptake.
2. Intense uptake in the large temporoparietal mass.
3. Transformation of a low-grade to a high-grade glioma.
4. No. Malignant tumors usually do not have receptors for
binding of the radiopharmaceutical, which is necessary
before intracellular incorporation.
Scintimammography in two different patients; A, a mammographically detected right breast mass; B, a palpable mass
adjacent to a right breast prosthesis.
1. What is the radiopharmaceutical? What is its mechanism of uptake?
2. Describe the imaging findings and give an interpretation.
3. What is the accuracy of conventional mammography and scintimammography for breast cancer?
4. What are causes of false-negative and false-positive findings on scintimammography?
Oncology: Scintimammography
1. 99mTc sestamibi lipophilicity allows it to enter the cell
where it is concentrated in the mitochondrial region related
to charge.
2. Patient A has prominent focal uptake in a right breast
mass. Patient B has definite focal uptake at the periphery
of the breast prosthesis.
3. Accuracy of conventional mammography: sensitivity, 70%
to 95%; positive predictive value for cancer, 20% to 30%.
Scintimammography multicenter trial: sensitivity/specificity,
75%/83%. Palpable lesion sensitivity, 87%; nonpalpable
lesion sensitivity, 71%.
4. Most false-negative findings are in lesions less than 1 cm.
False-positive findings occur in fibroadenomas and benign
and malignant tumors other than breast cancer.
A 53 year-old woman has recent onset of right upper quadrant pain and suspected acute cholecystitis. A, 60-minute
cholescintigraphy. B, 30-minute postmorphine acquisition.
1. Why is morphine used as an alternative to 3- to 4-hour delayed imaging?
2. In a patient with nonvisualization of the gallbladder at 60 minutes, what must be determined before morphine is
3. What is the accuracy of morphine cholescintigraphy?
4. What is the dose of morphine, and how long after injection is the image obtained?
Hepatobiliary System: Morphine-Augmented
1. Morphine produces contraction of the sphincter of Odcli,
which increases intraluminal common bile duct pressure.
Bile and excreted radiotracer then preferentially flow
through the cystic duct into the gallbladder if the cystic
duct is patent.
2. Exclude drug allergy. Do not give if evidence of common
duct obstruction, e.g., delayed filling or clearance of the
common duct or delayed biliary-to-bowel transit, exists.
3. The accuracy is at least as good, if not better, than the
delayed imaging method.
4. Intravenous administration of 0.04 mg/kg morphine, e.g.,
2.4 mg for a 60-kg patient. Images are acquired for an
additional 30 minutes.
A 53 year-old woman has recent onset of right upper quadrant pain and suspected acute cholecystitis. A, 60-minute
cholescintigraphy. B, 30-minute postmorphine acquisition.
1. Why is morphine used as an alternative to 3- to 4-hour delayed imaging?
2. In a patient with nonvisualization of the gallbladder at 60 minutes, what must be determined before morphine is
3. What is the accuracy of morphine cholescintigraphy?
4. What is the dose of morphine, and how long after injection is the image obtained?
Hepatobiliary System: Morphine-Augmented
1. Morphine produces contraction of the sphincter of Odcli,
which increases intraluminal common bile duct pressure.
Bile and excreted radiotracer then preferentially flow
through the cystic duct into the gallbladder if the cystic
duct is patent.
2. Exclude drug allergy. Do not give if evidence of common
duct obstruction, e.g., delayed filling or clearance of the
common duct or delayed biliary-to-bowel transit, exists.
3. The accuracy is at least as good, if not better, than the
delayed imaging method.
4. Intravenous administration of 0.04 mg/kg morphine, e.g.,
2.4 mg for a 60-kg patient. Images are acquired for an
additional 30 minutes.
A 43-year-old woman has a low-grade fever and abdominal discomfort 2 days after cholecystectomy.
1. Describe the cholescintigraphic findings.
2. Interpret the study.
3. What are possible causes for this problem?
4. What unique information does cholescintigraphy provide that is not obtainable from other diagnostic imaging
Hepatobiliary System: Biliary Leak
1. Rapid bile leakage probably originating from the region of
the ligated cystic duct and extending toward the right
colonic gutter and with time, over the dome of the liver.
2. Rapid biliary leak.
3. The most common cause is disruption of the cystic duct
ligature after cholecystectomy. Other causes for leak
include disruption of a surgical anastomosis, blunt or pen
etrating trauma, interventional radiographic procedures,
tumor, or inflammatory processes.
4. Confirm that fluid collections seen by anatomical imaging
modalities are biliary in nature. The rate of leakage also
can be estimated.
A 59-year-old man is referred with abdominal pain. CT reportedly showed a lesion of uncertain origin in the left lobe of the liver.
1. What is the radiopharmaceutical? What is the study?
2. What are the findings and the likely diagnosis?
3. How large must this lesion be to be seen on planar scintigraphy?
4. What are the advantages/disadvantages and accuracy of the radionuclide study?
Hepatobiliary System: Cavernous Hemangioma of the Liver
1. Tc-labeled red blood cells (RBCs). RBC liver scintigraphy.
2. Immediate images show no definite abnormality. Delayed images show increased focal uptake in the left lobe consistent with a cavernous hemangioma.
3. At least 2 cm.
4. Very specific (>99%) for hemangioma. Poor sensitivity for
small lesions.
Two patients undergo studies for gastrointestinal bleeding.
1. What radiopharmaceutical is used?
2. Determine the site of bleeding in study A.
3. Determine the site of bleeding in study B.
4. What is the slowest rate of bleeding that can be detected with scintigraphy and with contrast angiography?
Gastrointestinal System: 99mTc RBC Colonic
1. 99raTc-labeled RBCs.
2. A, Left colon, rectosigmoid region.
3. B, Right colon, hepatic flexure. It moves rapidly to the left
4. RBC scintigraphy, 0.1 ml/min; contrast angiography (1.0
A 5-year-old girl is referred after passage of a bloody stool.
1. What is the radiopharmaceutical, its mechanism of uptake, and study type?
2. Which pharmacological drugs can be used to enhance detectability? What is their mechanism?
3. Provide an interpretation.
4. Why is bleeding a common complication of this disease entity?
Gastrointestinal System: Meckel's
1. 99mTc pertechnetate Meckel's scan. The radiopharmaceutical
is taken up and secreted by gastric mucosa.
2. Pentagastrin increases rapidity, intensity, and duration of
uptake. It is used with glucagon, which has an antiperistaltic
effect that inhibits the rapid dispersion effect of
pentagastrin. Cimetidine, a histamine antagonist, increases
and prolongs uptake because of inhibition of 99mTc
pertechnetate secretion from gastric mucosal cells. It is
commonly used because of its lack of side effects.
3. Increasing focal uptake in the mid-abdomen suspicious for
Meckel's diverticulum; however, atypical timing of uptake
lessens the certainty. The uptake should be coincident with
gastric uptake in cases of Meckel's diverticulum. This may
be a false-positive scan.
4. Acid and pepsin secretion by the gastric mucosa produces
inflammation and ulceration of adjacent bowel mucosa.
A patient with insulin-dependent diabetes has chronic symptoms of early satiety, postprandial bloating, and abdominal
discomfort. A gastric emptying study is conduct 90 minutes after a solid meal.
1. What is the diagnosis?
2. What are normal values for solid meal gastric emptying?
3. What is the advantage of a solid radiolabeled meal over a liquid meal?
4. Why is attenuation correction recommended for accurate quantification of gastric emptying?
Gastrointestinal System: Diabetic Gastroparesis
1. Consistent with severe diabetic gastroparesis. Obstruction
cannot be ruled out.
2. Normal values are meal specific and depend on its
volume/composition, the method of acquisition, attenua
tion correction, processing, and quantification. Normal
values must be determined in each clinic or results of a
published method should be followed closely.
3. Solid (meat) or semisolid (egg) gastric emptying meals are
more sensitive for detection of mild to moderate delay in
emptying than studies conducted after a liquid meal.
4. Activity is detected with greatest efficiency close to the cam
era. The anterior view alone underestimates emptying, and
the posterior view overestimates it because of variable atten
uation as the meal moves through the stomach from the
posterior gastric fundus to the more anterior gastric antrum.
A 3-month-old infant was referred with symptoms of gastroesophageal reflux. A radionuclide gastroesophageal reflux
study (milk study) was performed (posterior view).
1. What are common symptoms and problems in children associated with reflux?
2. What other method is used by pediatricians for detection of reflux?
3. What radiolabel and what meal is used for this study?
4. How frequently should images be acquired to maximize sensitivity of this test?
Gastrointestinal System: "Milk" Study—
Gastroesophageal Reflux
1. Vomiting, pulmonary symptoms, asthma, pneumonia,
sudden death, failure to thrive, anemia.
2. 24-hour pH monitoring.
3. 99mTc sulfur colloid (1 mCi) in the child's usual feeding,
formula, or milk.
4. 5 to 10 seconds/frame.
A 65-year-old man with recent acute onset of right-sided hemiparesis undergoes 18F FDG-PET scanning.
1. What is the radiopharmaceutical used for metabolic cerebral imaging with PET, and what is the mechanism of
2. What are the radiopharmaceuticals used for PET cerebral perfusion imaging?
3. Describe this patient's PET imaging findings (above, transverse; middle, sagittal; bottom, transverse)?
4. What is the differential diagnosis?
Central Nervous System: Cerebral Infarct
1. 18F PET-FDG is dependent on glucose metabolism.
2. SPECT 99mTc HM-PAO and ECD are cerebral perfusion
agents that are lipid soluble, distribute according to
cerebral blood flow (gray to white matter, 3:1 to 4:1), and
fix intracellularly.
3. Wedge-shaped severe decreased metabolism in the left
posterior parietal region in a vascular posterial parietal
4. Cerebral hemorrhage, infarct, and neoplasm.
A 45-year-old woman with cervical carcinoma has new bilateral hydronephrosis demonstrated on CT scanning.
1. Describe the scintigraphic findings before and after furosemide administration.
2. Interpret the study before laser administration.
3. Interpret the study after laser administration.
4. List some limitations of diuretic renography.
Diuretic Renography: Unilateral Obstruction
1. Good symmetrical cortical uptake and prompt excretion into collecting systems bilaterally. Retention of activity in left renal collecting system, apparent cutoff in the upper ureter, and very poor response to furosemide. The right side shows a prominent collecting system but washes out spontaneously before furosemide administration.
2. Hydronephrosis of the left kidney. Rule out obstruction.
3. Consistent with significant obstruction of the left kidney.
4. Dehydration, renal insufficiency, inadequate diuretic dose, full bladder, large collecting system.
A 5-year-old girl has had two urinary tract infections in the past 6 months.
1. Which radiopharmaceuticals commonly are used for cystography?
2. What is the advantage of radionuchde cystography over the contrast study?
3. What is the difference between indirect and direct radionuclide cystography?
4. How is reflux graded with radionuclide cystography?
Radionuclide Cystography
1. 99mTc DTPA and WmTc sulfur colloid are the two most
commonly used.
2. Radionuclide cystography is more sensitive in detection of
vesicoureteral reflux (VUR) and results in 50 to 200 times
less radiation exposure to the gonads compared with the
contrast study.
3. The direct method is commonly used and requires urinary
catheterization and instillation of radiotracer into the bladder
through a catheter. The indirect method is performed after
routine renography with 99mTc DTPA/mercaptylacetyltriglycine
(MAG3). When the bladder is full, a prevoiding
image is obtained, followed by dynamic images during and
after voiding.
4. Grading criteria are similar to those used with contrast cys
tography; however, the radionuclide study's limited resolu
tion does not permit assessment of calyceal morphology.
Mild reflux: confined to the ureter. Moderate: reaches the
pelvicocalyceal system. Severe: distorted collecting system
and dilated tortuous ureter.
A 35-year-old renal transplant patient has three renal studies (sequential images over 30 minutes) using 99mTc DTPA
on one day and 99mTc MAG3 and 13II hippuran 1 week later.
1. Which renal radiopharmaceutical is used for each study: A, B, and C?
2. What is the mechanism of uptake of the three radiopharmaceuticals?
3. What are the advantages and disadvantages of each radiopharmaceutical?
4. Can a blood flow (radionuclide angiogram) study be done with all three agents? Why?
Renal Radiopharmaceuticals
1. A, 99mTc DTPA; 5, 99mTc MAG3; C, I31I hippuran.
2. DTPA: glomerular filtration; MAG3: tubular secretion;
hippuran: 20% glomerular, 80% tubular.
3. DTPA is inexpensive, provides a good image quality, but has
low extraction efficiency (10% to 20%) and poor quality
images with renal insufficiency. MAG3 has a high extraction
rate (60%), good target to background, and good-quality
images with renal insufficiency. Hippuran has good extrac
tion efficiency, high target-to-background, poor image qual
ity, poor cortical/collecting system differentiation, and deliv
ers a high radiation dose in renal insufficiency.
4. No. The administered dose of 131I hippuran is too low
(200 to 300 |xCi), limited by the high radiation absorbed
dose. A dose of 5 mCi is needed for good blood flow images.
A 31-year-old man with a history of congenital ureteropelvic junction obstruction had surgical correction several years
ago. The most recent diuretic renogram was interpreted as right renal obstruction. This scan was obtained after the
second surgical correction.
1. Describe the scintigraphic imaging findings before and after administration of furosemide.
2. What is your interpretation of the study?
3. Can ureteropelvic vs. ureterovesical obstruction be distinguished from this study?
4. What is the Whittaker test?
Genitourinary System: Diuretic
Renography/Nonobstructed Hydronephrosis
1. Bilateral prompt cortical uptake and excretion into collecting
systems. Retention in the right collecting system at 30 min
utes with good post-furosemide washout.
2. Good response to surgical correction. Negative for
3. Not with certainty. Ureteral nonvisualization is not diagnos
tic of ureteropelvic junction obstruction because a standing
column of ureteral urine can prevent radiotracer entry.
4. It measures pressure-flow relationships and requires fluoroscopically
guided trocar or spinal needle insertion into the
renal pelvis. Basal and pressure measurements during infu
sion of a contrast solution at a set rate are recorded.
Obstruction pressure is defined as greater than 15 cm
water, no obstruction as less than 10 to 12 cm water.
A 30-year-old kidney transplant recipient has decreasing postoperative urine output, fullness and tenderness around
the graft, and scrotal swelling 24 hours after surgery.
1. Describe the findings on the 25-minute dynamic renal scintigraphy.
2. What is the diagnosis?
3. What are other causes of postoperative fluid collections adjacent to the graft?
4. What are other common complications during the first weeks after transplantation?
Genitourinary System: Transplant Kidney
Urinary Leak
1. Rapid leakage of urine just inferior to the transplanted
lcidney and extravasating into the scrotum.
2. Urinary leak caused by disruption of the surgical
3. Hematomas and abscesses occur in the early postoperative
course, whereas lymphoceles generally are noted 4 to 8
weeks after surgery.
4. Acute tubular necrosis, acute rejection, obstruction. Cyclosporin
toxicity usually occurs months after transplantation.
Radionuclide blood flow and early dynamic images at 24 hours after transplantation.
1. What are the scintigraphic findings?
2. What is your physiologic interpretation?
3. What is the differential diagnosis?
4. What therapy would be appropriate
Genitourinary System: Nonviable Kidney After
1. No blood flow to the transplanted kidney. No renal
uptake. A photopenic region in the shape of the trans
planted kidney.
2. Nonviable kidney.
3. Arterial or venous thrombosis, severe irreversible rejection,
acute cortical necrosis.
4. Removal of the nonviable transplanted kidney.
A 25-year-old man undergoes imaging 3 days after a renal cadaver transplant.
1. Which postoperative complications occur in the first week of renal transplantation?
2. During which postoperative period does acute rejection typically occur?
3. What are the scintigraphic findings in this case?
4. What is the diagnosis?
Genitourinary System: Renal Transplant with
Acute Tubular Necrosis
1. Acute tubular necrosis, accelerated acute rejection, urinary
leak, urinary obstruction.
2. The second postoperative week. Accelerated rejection may
occur during the first week in patients who have had previ
ous transplants or received multiple transfusions.
3. Normal blood flow, very poor function, no excretion. Base
of penis seen inferiorly.
4. The pattern of normal blood flow but poor function dur
ing the first week after transplantation is typical of acute
tubular necrosis (ATN).
An 8-year-old boy has acute onset of right testicular pain.
1. What is the radiopharmaceutical and mechanism of distribution?
2. What are the most common causes of acute testicular pain?
3. What is the mechanism of testicular torsion?
4. What are the imaging findings, and what is the diagnosis in the case?
Genitourinary System: Testicular Torsion
1. 99mTc pertechnetate, initial blood flow, and then the radiotracer
distributes in the extracellular fluid space (intravascular
and interstitial).
2. Actite epididymitis, testicular torsion, torsion of the testic
ular appendage.
3. Developmental abnormality of testicular descent and attach
ment predisposes to spermatic cord torsion. The most com
mon anatomical abnormality is "bell-clapper" testis.
4. Decreased blood flow to the right testicle and a photopenic
right testicle consistent with acute testicular torsion.
A 48-year-old woman has recent onset of neck tenderness and hyperthyroidism (thyroid-stimulating hormones [TSH]
<0.05 |xU/ml); 123I scan uptake (radioactive iodine uptake [RAIU]) <1%). Right side (R); suprasternal notch (SSN).
1. What is the clinical differential diagnosis of hyperthyroidism?
2. What is the clinical purpose of the thyroid scan and RAIU tests in hyperthyroidism?
3. How is the RAIU calculated?
4. What is the likely diagnosis in this patient?
Endocrine System: Hyperthyroidism/
1. Graves' disease, toxic nodule(s), thyroiditis (subacute,
silent, postpartum), iatrogenic thyroid hormone ingestion,
iodine-induced (Jod Basedow), trophoblastic tumors
(hydatidiform mole and choriocarcinoma), Hashitoxicosis,
ectopic hyperfunctioning thyroid tissue (struma ovarii).
2. Aid in the differential diagnosis of hyperthyroidism.
3. A nonimaging gamma probe obtains counts/time from the
neck and a phantom-containing activity equal to the orally
administered dose (u,Ci) to convert the gamma probe
counts to |JiCi. %RAIU = neck (|xCi) divided by the total
administered dose (|xCi) after background correction.
4. Subacute thyroiditis based on the history of neck tender
ness, laboratory finding, and RAIU.
A 35-year-old woman with hyperthyroidism. Radioactive iodine uptake was 94% at 4 hours and 81% at 24 hours.
1. Describe the difference between Graves' disease and euthyroid scan appearance.
2. What is the appropriate therapy for Graves' disease?
3. What are the usual administered doses of radiotracer for "'I uptakes, 123I scans, and Graves' disease therapy?
4. What are the short-term and long-term side effects of 131I therapy for hyperthyroidism?
Endocrine System: Graves' Disease
1. Scan appearance may be similar. With a large goiter the
scan often has a plumper appearance with convex borders.
The pyramidal lobe may be seen, as in this case.
2. Surgery is seldom performed because of the high risk.
Propylthiouracil (PTU) and methimazole (Tapazole)
sometimes are used initially, particularly in patients with
severe disease who require "cooling down," young chil
dren, and pregnant patients. Most of these are treated with
radioactive iodine after 6 to 12 months of antithyroid
medication. Many patients are treated initially with 131I.
3. 131I uptake (10 (xCi), 123I scan and uptake (300 |xCi),
Graves' disease therapy: 131I (5 to 15 mCi)
4. Short-term: occasional exacerbation of hyperthyroidism,
cardiac symptoms in elderly, very rare thyroid storm.
Long-term: hypothyroidism. There is no increased inci
dence of secondary cancers, reduction in fertility, or con
genital defects in offspring.
A 39-year-old woman 6 weeks previously underwent total thyroidectomy for thyroid cancer. Scanning was done 7 days
after therapy for thyroid ablation with 75 mCi of 131I.
1. Describe and interpret the scintigraphic images.
2. What is the reason for the star artifact pattern in the neck in scan A?
3. What collimator was used for image B?
4. Why is the liver seen in image A?
Endocrine System: 131I Star Artifact
1. A, Posttherapy I31I whole-body scan shows intensive uptake
in the neck with a "star" artifact, diffuse liver activity, and
bladder clearance. The mediastinum is difficult to visualize
because of the artifact. B, Pinhole image of the neck with
three foci of uptake.
2. Septal penetration of high-energy 131I gamma rays through
the collimator septa.
3. Pinhole collimator centered on the thyroid.
4. Radiolabeled thyroid hormone is metabolized in the liver.
This usually is seen only on the posttherapy scans.
A 12-year-old boy has recent onset of back pain. The report of outside radiographs was equivocal.
1. Describe the bone scan findings on the planar images (A) and reprojection SPECT (B) images.
2. Describe the findings on the transverse and coronal SPECT slices (Cand D).
3. Provide a differential diagnosis and the most likely diagnosis.
4. This entity may be associated with an abnormality of alignment. Describe it.
Skeletal System: L5 Pars Interarticularis Defect
1. The bone scan demonstrates focal increased uptake in the
lateral aspect of L5 vertebra.
2. The finding is better demonstrated and better localized on
the SPECT images, where the abnormal uptake is clearly
seen in the region of the left pars interarticularis/facet joint.
3. L5 unilateral pars interarticularis defect, degenerative or
posttraumatic facet disease. Pars defect is the most likely
diagnosis in this age group.
4. Spondylolisthesis or slippage of the vertebrae out of nor
mal alignment can occur if the defect is bilateral.
A 5-year-old boy with low-grade fever and pain in the right knee was referred for a three-phase bone scan.
1. Describe the three-phase scintigraphic findings.
2. Provide a differential diagnosis.
3. Do these findings suggest a septic arthritis?
4. What other radionuclide study could confirm or exclude infection?
Bone: Tibial Osteomyelitis—Three-Phase
Positive Bone Scan
1. Increased blood flow (A), blood pool (B), and uptake on
delayed images (C) in the proximal metaphyseal region of
the right tibia.
2. Osteomyelitis, bone tumor, fracture/osteotomy.
3. No. A bone scan with septic arthritis shows increased
uptake at the end of long bones symmetrically on both
sides of the joint. An asymmetrical appearance may be
seen if osteomyelitis and septic arthritis coexist; however,
this study reveals normal findings on the femoral side.
4. 99mTc HM-PAO-labeled leukocyte study in a child.
An 11-month-old infant has a hepatic mass on ultrasound. Bone scan ordered to exclude bone metastases.
1. Describe the scintigraphic findings.
2. Besides a neoplastic process, what other conditions could be associated with the findings?
3. Name another likely origin of the tumor other than the liver.
4. What is the most likely diagnosis?
Skeletal System: Hepatoblastoma
1. Nonuniform abnormal soft tissue right upper quadrant up
take that cannot be clearly separated from the right kidney.
2. Trauma to soft tissue or organs, in this case, the liver,
resulting in contusion or hematoma, ischemic injury
(although the pattern appears round rather than suggestive
of a vascular distribution), chronic abscess.
3. Adrenal: neuroblastoma.
4. Given that it is a hepatic mass, hepatoblastoma is most likely
based on the patient's age and uptake of bone radiotracer.
Two patients have knee pain, with no fever or calor. Patient A: bone scan and radiograph. Patient B: bone scan.
1. Describe the abnormal three-phase bone scan findings for patients^ and B.
2. What other general information about the patients is evident from the bone scans?
3. Provide a differential diagnosis and the most likely diagnoses for each patient.
4. What term is commonly used to describe the pattern seen on delayed images in B?
Skeletal System: Osteosarcoma
1. A, Increased blood flow (above) and blood pool (below, left)
to the right distal femur and increased uptake on delayed
images in the distal femoral metaphysis extending to the
joint surface (below, right). Mild increased uptake in die
proximal tibia probably the result of hyperemia. B, Radio
graph: mixed lytic-sclerotic lesion of die distal femur with
cortical destruction and indistinct margins. No periosteal
reaction. C, Abnormal increased flow and blood pool to die
left distal femur with delayed increased uptake in spiculated
pattern extending beyond the femoral contour.
2. The patients are skeletally immature but near the mature
stage. Physes are seen faintly on delayed images, indicating
that fusion is imminent. These are teenagers.
3. A, Monostotic primary neoplasm, e.g., osteosarcoma, sec
ondary neoplasm, or osteomyelitis. B, Characteristic sun
burst pattern of osteosarcoma.
4. Sunburst pattern.
Two young adults were referred for a bone scan. Patient A has thoracic pain, and patient B has hip pain.
1. Describe the scintigraphic findings in both patients.
2. What is the diagnosis and cause for this pattern of uptake in these patients?
3. What is the mechanism of radiopharmaceutical uptake?
4. What are other causes of uptake in muscle?
Skeletal System: Muscle Injury
1. A, Uptake in teres major muscles bilaterally. B, Bilateral
uptake in the adductor magnus muscles of the thighs.
2. Soft tissue muscle injury caused by repetitive stress; weight
lifting in A, and stair climber exertion in B.
3. Soft tissue deposition of 99mTc-labeled diphosphonates is
caused by binding to microcalcifications at sites of injury
and possibly binding to injured immature collagen.
4. Rhabdomyolysis, iron dextran injection, polymyositis, myositis
ossificans, ischemia, electrical injuries, direct trauma.
1. Describe the bone scan findings.
2. Name structures where the tracer could be deposited.
3. Provide the differential diagnosis.
4. What other information would be helpful?
Skeletal System: Pleural Uptake
1. Abnormal soft tissue uptake in the anterior left hemithorax;
scoliosis and mild arthritic changes in both hips.
2. Starting on the inside working outward: in the lung
parenchyma, in a primary or secondary tumor in the lung,
in the pleural or pleural effusion, in the soft tissue of the
chest wall.
3. Extensive pleural calcification, fibrothorax, prior radiation.
4. History, chest radiograph, or SPECT.
1. What are possible explanations for the change in the patient's bone scan from A to B?
2. List three questions that would be helpful to limit the differential diagnosis in A/B.
3. Describe the bone scan findings in patient C. Ignore the rectangular region of interest.
4. Provide the most likely diagnosis for the scans A/B and C.
Skeletal System: Hot Kidneys, Radiation
Nephritis, and Spinal Photopenia
1. Increased radiotracer is present in both renal cortices in a
bilateral symmetrical pattern on the follow-up study that
was not seen on the initial study.
2. Has the patient been treated with a new medication in the
interval since the prior bone scan? Has the patient had
recent intravenous contrast media? Has the patient had
restricted fluid intake?
3. Increased activity in the upper portions of both kidneys
and cold lower thoracic spine.
4. A/B, Chemotherapy-induced interstitial nephritis. C, Prior
radiation therapy to the spine with radiation nephritis.
1. Describe the advantage of whole body imaging for the technologist compared with spot imaging, which was used
in this case.
2. Describe the advantage of whole body imaging for the physician.
3. Describe the abnormality
4. Provide the differential diagnosis.
Skeletal System: Splenic Uptake
1. Less camera repositioning and time for the technologist.
2. Easier for the physician to check for quality assurance and
for interpretive review.
3. Intense abnormal uptake in a structure that appears to be
an enlarged spleen by its location and configuration.
4. Blood dyscrasias, including siclde cell disease, sickle thalassemia,
thalassemia major; hemosiderosis; extensive subcapsular splenic hematoma.
The bone scan image and radiograph of a paraplegic patient are provided.
1. Describe the bone scan findings.
2. Provide a differential diagnosis.
3. What interventions could be performed if artifact is suspected?
4. Radiograph of the right hip was obtained after the bone scan. What is the most likely diagnosis?
Skeletal System: Heterotopic Ossification
1. Radiotracer in a full urinary bladder obscures the central
portion of the bony pelvis. Intense activity is seen overlying the right acetabulum with a separate area of uptake
overlying the proximal right femur.
2. Urinary contamination; fracture with exuberant callus;
heterotopic ossification or myositis ossificans; soft tissue
injury (contusion).
3. If urinary contamination is suspected: remove clothing
and overlying bed sheets; wash the patient's skin in the
area of suspected contamination.
4. Heterotopic ossification.
Elevated alkaline phosphatase level.
1. Describe the bone scan findings.
2. Name two other nonosseous systems that should be evaluated on the bone scan.
3. Describe any other findings.
4. What term can be applied to this case?
Skeletal System: Superscan Secondary to
Metastatic Prostate Cancer
1. Increased radiotracer in the large majority of the visualized
bones, with nonuniform involvement particularly evident
in both femurs, both humeri, and skull.
2. Soft tissues and genitourinary tract.
3. The kidneys are not visualized, but faint activity is seen in
the urinary bladder. Little soft tissue activity is seen.
4. Superscan.
A 56-year-old was admitted after a seizure and fall. Brain CT demonstrates multiple cerebral masses. Whole body bone
scan (A) and multiple transverse SPECT images of the chest (B) are shown.
1. Describe the skeletal abnormalities.
2. Describe any other abnormalities.
3. What is the most likely diagnosis?
4. Name 3 liver primary or metastatic tumors that have increased bone tracer uptake.
Skeletal System: Soft Tissue Uptake
in Lung Mass
1. Focal abnormal uptake in the right and left anterior ribs,
right upper posterior rib, and sternum.
2. Abnormal diffuse radiotracer uptake in the right upperchest
on the anterior and posterior views, which does not
conform to normal bone configuration. Selected SPECT
images demonstrate the uptake to be in a large ovoid mass
within the right lung.
3. Lung cancer with brain metastases. The bone scan abnor
malities are likely traumatic because of the distribution
and history of a fall.
4. A high percentage of neuroblastomas involving the liver
have bone tracer uptake, and a much smaller percent of
metastases from lung, breast, and colon cancer, especially
mucinous cancers.
A 55-year-old man has low back pain and no prior history. Bone scan images, anterior and posterior views.
1. Provide a general distribution for the bone abnormalities.
2. Describe the findings.
3. List three factors that help limit the differential diagnosis.
4. What is the most likely diagnosis?
Skeletal System: Prostate Cancer Bone
Metastases, Axial Distribution
1. Spine and pelvis.
2. Abnormal focal and regional activity is seen in multiple
sites in the sacrum, both ilium, both inferior pubic rami,
right superior pubic ramus, mid-thoracic and lower thoracic spine. Note the incidental calcification of costochondral cartilage.
3. Multiple lesions, axial predominance, older adult man.
4. Multiple skeletal metastases from prostate cancer.
A 53-year-old woman with hypercalcemia was referred to rule out metastatic bone disease.
1. Describe the bone scan findings.
2. Give a differential diagnosis.
3. Provide the most likely diagnosis.
4. Could this pattern be caused by free 99mTc pertechnetate? Why?
Skeletal System: Hyperparathyroidism
1. Abnormal diffuse uptake in the lungs and stomach. Poor
visualization of small kidneys and bladder, increased
uptake in the shoulders, hips, knees, and ankles.
2. Hyperparathyroidism, metastatic calcification caused by
hypercalcemia, renal failure or both, metabolic bone disease.
3. This particular pattern of metastatic calcification is charac
teristic of long-standing hyperparathyroidism. Although
other causes of metabolic bone disease, e.g., osteomalacia
and renal osteodystrophy, result in abnormal bone scans,
they do not have this characteristic pattern. This scan
pattern is seen in hyperparathyroidism.
4. Free 99mTc pertechnetate has gastric, thyroid, and salivaty
gland uptake. The latter two are not seen in this patient,
who also shows large uptake.
An initial bone scan (A) and repeat study 2 years later (B).
1. Describe the bone scan abnormalities on the initial study (A).
2. Describe the skeletal abnormalities on the follow-up study (B).
3. List the differential diagnoses.
4. Provide the most likely diagnosis.
Bone: Osteosarcoma Metastatic to Lung
1. A, Abnormal decreased and increased uptake in the left
humerus (proximal and mid, respectively).
2. B, Irregular uptake in the chest anterior and posterior
views indicates location midway between in the lung
parenchyma. Uptake is nodular and masslike. Rib abnor
malities cannot be excluded, but the pathological condi
tion extends across the rib spaces. Left shoulder arthroplasty
is shown by photopenia.
3. The differential diagnosis for abnormal lung activity in a
focal pattern includes primary lung tumors and metastases,
especially for tumors with calcific or ossific components.
For abnormal lung activity in a regional pattern, not evi
dent in this case, the differential diagnosis includes malig
nant pleural effusion, fibrothorax, or radiation therapyinduced
4. Osteosarcoma of the left proximal humerus, status/
post-arthroplasty, with lung metastases.
Diffuse upper extremity pain was noted 3 months after thoracotomy. Hand radiographs show normal findings. The remainder of the bone scan is normal.
1. Describe the scintigraphic bone scan findings in this case (palms down on the camera).
2. Provide the differential diagnosis.
3. What is the likely diagnosis in this case?
4. Discuss the pathogenesis.
Skeletal System: Reflex Sympathetic
1. Three-phase study demonstrates abnormal increased blood flow and blood pool of the distal right upper extremity. The delayed bone phase shows increased activity in the bones in the same distribution, with a striking increase in periarticular activity causing the joints to stand out.
2. Reflex sympathetic dystrophy syndrome (RSDS), disuse of a limb of new onset, e.g., recent stroke or immobilization by orthopedic cast or splint.
3. Shoulder-hand syndrome, a frequently encountered form of RSDS.
4. Neurogenic origin with loss of sympathetic autonomic tone is the generally accepted explanation, although not firmly established.
An elderly patient has had right knee pain for 3 months. Radiographs at onset were reported as normal.
1. Describe the bone scan findings. A, above: flow; A, below: blood pool and delayed images.
2. Based on the scan findings, provide a differential diagnosis.
3. A radiograph then was obtained (B). Given all available information, what is the most likely diagnosis?
4. What are common causes for this condition in the femoral head?
Skeletal System: Spontaneous Osteonecrosis
of Distal Femur
1. Increased activity in the medial femoral condyle on all
three phases of the bone scan.
2. Osteonecrosis, fracture, osteoarthritis, primary bone neo
plasm (unlikely with prior normal radiograph).
3. Spontaneous osteonecrosis of the medial femoral condyle.
4. Trauma, steroid therapy, vasculitis, infarction (siclde cell,
Gaucher's disease), alcoholic, caisson disease.
A patient has back pain and elevated serum alkaline phosphatase concentration.
1. What is the mechanism of uptake of bone scan agents?
2. Describe the bone findings. Describe any other soft tissue findings.
3. What is the most likely diagnosis?
4. List three possible primary neoplasms.
Skeletal System: Metastases to Bone and Liver
1. Uptake is dependent on blood flow and adsorption to the
hydroxyapatite crystal.
2. Abnormal focal uptake in the skull, scapulae, ribs, spine,
pelvis, and left femur. Diffuse uptake in the majority or
entire liver.
3. Malignant metastases to bone and liver.
4. Breast, colon, lung.
A bone scan was ordered because an elderly man "hurts all over." The remaining bone scan (not shown) was otherwise
1. Describe the 99mTc disphosphonate bone scan findings.
2. In terms of anatomical location, where is the abnormal radiotracer uptake?
3. What other radiopharmaceutical would give a similar appearance?
4. What is the differential diagnosis?
Skeletal System: Myocardial Uptake
1. Curvilinear "horseshoe" pattern of uptake in the anterior
chest that does not correspond to normal bony anatomy
and therefore is most likely abnormal soft tissue uptake.
2. Cardiac uptake, either the myocardium or pericardium.
3. 99mTc pyrophosphate.
4. Idiopathic or secondary cardiomyopathy, e.g., due to cardiotoxic
drugs, myocarditis, cardioversion injury, myocar
dial contusion, ventricular aneurysm, infarction, severe
unstable angina, pericarditis with or without calcification,
Patient has known breast cancer metastatic to bone. Initial bone scan (A) and scan 6 months later (B and C) are submitted.
1. Describe any interval change.
2. Describe the findings in C.
3. Where is the skull abnormality most likely located?
4. What is the most likely explanation?
Skeletal Metastases: Metastasis to Clivus
1. Increased intensity of activity is seen in the nasal region on
the anterior view and midline occiput on the posterior
view and left sixth and seventh costochondral junctions
and left radial head uptake (not injection site).
2. The skull abnormally increased activity projects over the
temporomandibular joint region on the right and left
lateral skull images.
3. Skull base in the midline.
4. Metastasis to clivus; other skeletal metastases appear stable.
Two patients are shown. ^4, A 10-year-old boy was referred for a bone scan because of back pain. B, A 60-year-old man
with new lung cancer. Bone scan and CT scan are provided.
1. Describe the bone scan findings in both patients.
2. Give a differential diagnosis for these abnormalities.
3. Describe the extraosseous soft tissue abnormality in B.
4. What are the two most likely causes for the soft tissue abnormality?
Skeletal System: Cold Spine Defects
1. A, Cold defect in Tl 1. B, Decreased activity at approxi
mately T6.
2. Benign or malignant tumor, osteomyelitis, avascular necro
sis, congenital or surgical defect, artifact, radiation therapy.
3. Intense renal cortical uptake (cortical staining).
4. Nephrotoxic antibiotics or chemotherapeutic agents asso
ciated with interstitial nephritis.
A patient has abnormal blood chemistry test results. Selected images from a bone scan are submitted printed in normal
and dark modes.
1. Describe the findings.
2. Name two features that help to narrow the diagnosis.
3. List other findings outside the chest that can help to narrow the differential diagnosis.
4. Provide the most likely diagnosis.
Skeletal System: Metastatic Calcification in
Lungs and Kidneys
1. Abnormal bilateral lung activity; increased activity in the
renal parenchyma; kidneys appear enlarged.
2. The findings are bilateral and uniform. Two different
organs are involved.
3. Tracer uptake in the stomach would suggest
4. Metastatic calcification caused by hypercalcemia associated
with renal insufficiency.
Provide the probable cause and give your recommendations for the abnormal gamma camera quality control floods.
1. A.
2. B.
3. C. Overnight change.
4. D. Change since prior patient that day.
Quality Control: Gamma Camera Floods
1. Cracked crystal (buy a new crystal).
2. Nonfunctioning photomultiplier tube (call service).
3. Distorted (not circular) and nonuniform image. Electronic
tuning required. The power went off overnight. Call the
service representative.
4. Contamination of crystal with radiopharmaceutical.
(Clean camera or allow radiotracer to decay 10 half-lives.)
A 50-year-old patient with diabetes achieved 4.0 METS (metabolic equivalent) and 60% of maximum age-predicted
heart rate (MPHR) on the exercise treadmill stress test.
1. When should the exercise treadmill stress test be discontinued?
2. Describe the myocardial stress and rest perfusion SPECT image findings.
3. Provide the differential diagnosis and likely involved vessel(s).
4. Discuss any other factor important to the interpretation of the scan.
Cardiovascular System: Inferior Lateral
Wall Infarction
1. If the patient develops severe anginal chest pain, a decrease
in blood pressure, frequent premature ventricular contrac
tions (PVCs), or ST-T wave elevation suggestive of acute
infarct. Also if the patient can walk no further on the
treadmill because of general fatigue, leg pain, or dyspnea.
2. Severe stress and rest fixed defect in the basal lateral,
inferior, and inferolateral walls, sparing the apex.
3. Myocardial infarction or possibly hibernation. Circumflex
4. The exercise stress level.
A 53-year-old man who had a recent myocardial infarction had a dipyridamole stress myocardial SPECT study before hospital discharge. SPECT short-axis (A) and vertical long-axis (B) images are shown.
1. Describe the SPECT findings.
2. Name the likely coronary artery or arteries involved.
3. Provide the differential diagnosis.
4. What prognostic information does the scan provide?
Cardiovascular System: Dipyridamole-lnduced Reversible Inferior Wall Ischemia
1. A perfusion defect involving the entire inferior wall
extending to the apex shows partial reversibility.
2. Right coronary artery.
3. Inferior wall ischemia with incomplete reversibility. The
latter may represent scar (infarct) or hibernating myocardium.
4. The patient is at risk for a further cardiac event, either
myocardial infarct or death.
SPECT adenosine stress/rest myocardial perfusion images. SPECT short-axis (A), vertical long-axis (B), and horizontal long-axis (C) images are shown.
1. Describe the procedure for adenosine stress (a), adenosine's duration of action (b), and the procedure to deal with
side effects of adenosine (c).
2. List contraindications to the use of intravenous adenosine.
3. Describe the SPECT findings and the diagnosis.
4. What are clinical indications for adenosine stress?
Cardiovascular System: Adenosine Stress/
Apical Infarct, Anterior-Lateral Ischemia
1. (a) Adenosine is infused intravenously for 6 minutes
(140 |xg/kg/min). After 3 minutes the radiotracer is
injected and adenosine is continued for 3 more minutes,
(b) Adenosine is cleared rapidly from the circulation
(tj, <10 seconds). Return to baseline blood flow levels
occurs in 2 to 3 minutes after stopping the infusion, (c)
Stop the infusion.
2. Sinus node disease, second- or third-degree atrioventricular
(AV) block, bronchospastic lung disease, adenosine allergy.
3. Small to moderately severe fixed defect at the apex on both
stress and rest images consistent with infarct. Mildly
improved perfusion of the anterior and lateral walls at rest
compared with stress consistent with mild anterolateral
4. Whenever adequate exercise stress is not possible.
A 55-year-old man with CAD but no history or ECG evidence of myocardial infarction. SPECT short-axis (A), vertical long-axis (B), and horizontal long-axis (C) are shown.
1. Describe the findings on the SPECT.
2. Provide the differential diagnosis.
3. Describe the blood flow and functional state of hibernating myocardium.
4. Describe the blood flow and functional state of stunned myocardium.
Cardiovascular System: Viability,
Fixed LAD Defect
1. Extensive fixed defects involving the anterior wall, apex,
septum, extending to the lateral wall.
2. Myocardial infarction versus hibernating myocardium
3. In hibernating myocardium, blood flow and function, e.g.,
contractility, are chronically reduced.
4. Blood flow is normal, recently restored after an acute
occlusive state; function is reduced.
1. Describe the bull's-eye format for SPECT myocardial perfusion studies.
2. List possible errors that may occur when applying a bull's-eye quantitative analysis technique to myocardial perfu
sion SPECT.
3. Describe the findings and the likely culprit coronary artery or arteries. Does the bull's-eye plot confirm the image
4. List the characteristics of perfusion scan abnormalities that should be included in any report.
Cardiovascular System: Bull's-Eye,
Reporting Results
1. A polar plot is constructed by layering short-axis slices one
on top of the other, with the apex forming the center and
the base of the heart being the outermost portion.
2. Misregistration/misalignment, use of inappropriate refer
ence database.
3. Stress: hypoperfusion of the anterior, lateral, and inferior
walls. Rest, normalized perfusion of the anterior and lateral
walls and incomplete normalization of the inferior wall.
Most consistent with ischemia of the left circumflex and
infarct of the right coronary artery. The bull's-eye confirms
the image findings.
4. Include location and extent, severity, and reversibility for
each perfusion abnormality. If gated SPECT is performed,
include LVEF, wall motion, with or without wall thicken
ing fractions. Note ancillary signs of significant CAD, e.g.,
increased 201Tl lung activity, or stress-induced dilation of
the left ventricle, if present.
A patient had atrial fibrillation and high baseline resting heart rate. The patient exercised for only 3.5 minutes,
achieved only 3.0 METS, but reached 100% of age-predicted maximum heart rate. SPECT short-axis (A) and hori
zontal long-axis perfusion images (B).
1. Describe any perfusion abnormalities.
2. Describe any other findings.
3. What is the most likely culprit coronary artery?
4. Discuss the significance of failure to achieve adequate exercise.
Cardiovascular System: Inadequate Stress
1. Severe fixed defect involving the entire lateral wall.
2. Dilated left ventricular cavity at both stress and rest.
3. Left circumflex coronary artery.
4. False-negative studies for ischemia may result.
A 60-year-old patient with diabetes has severe chronic obstructive pulmonary disease (COPD) and uses a walker; he
denies chest pain. Short-axis (A) and horizontal long-axis (B) SPECT myocardial perfusion images are presented.
1. What form of stress is indicated for this patient and why?
2. Describe the perfusion abnormalities.
3. What is the likely culprit coronary artery?
4. Explain the discrepancy between the findings and patient's lack of symptoms.
Cardiac: Silent Lateral Wall Ischemia
1. Dobutamine. The need of a walker precludes adequate
exercise stress, and COPD is a contraindication to adeno
sine or dipyridamole use.
2. Moderately severe perfusion defect involving the entire lat
eral wall extending to the anterolateral, inferolateral
regions, and apex on the stress images that nearly normal
izes on the rest images. Incomplete reversibility of small
portion of inferior wall.
3. Left circumflex coronary artery.
4. Silent myocardial ischemia.
A 55-year-old woman with abnormal baseline ECG and left bundle branch block (LBBB) is sent for a stress dualisotope
SPECT study. LVEF and wall thickening by gated SPECT are normal.
1. Name the appropriate stress technique.
2. List stress methods that would be disadvantageous in this patient and state the reason.
3. Discuss the physiological advantage of adenosine or dipyridamole compared with other stress methods.
4. Describe the scintigraphic findings.
Cardiovascular System: LBBB
1. Dipyridamole or adenosine.
2. Exercise or dobutamine. Methods of stress that result in
increased heart rate can be associated with false-positive
findings of septal reversibility (identical to isolated septal
ischemia) in patients with LBBB.
3. These agents do not result in an increase in heart rate.
4. The mild decreased activity in the anterior wall appears
fixed and likely is caused by breast attenuation in light of
the reported normal wall motion.
Gated radionuclide ventriculogram (RVG or MUGA) was performed.
1. Name the radiopharmaceutical used.
2. List methods for preparation of this radiopharmaceutical.
3. Describe the methodologies of radiolabeling.
4. List the advantages and disadvantages of the different labeling methods.
Cardiovascular System: RBC Labeling
1. 99mTc-labeled RBCs.
2. In vivo, modified in vivo, and in vitro methods.
3. In vivo: stannous pyrophosphate is administered intra
venously, followed in 15 to 30 minutes by 99mTc pertechnetate.
Modified in vitro: stannous pyrophosphate is adminis
tered intravenously and 15 to 30 minutes later, 3 to 5 ml
of blood is withdrawn into an attached shielded syringe
containing 99mTc pertechnetate and an anticoagulant, either
acid-citrate-dextrose (ACD) or heparin. The blood is incu
bated for 10 minutes and periodically agitated, then infused.
The syringe is left attached to the indwelling intravenous
line during the procedure so that the entire system is closed.
In vitro: blood is withdrawn and placed in a closed vial
containing stannous chloride and sodium hypochlorite to
oxidize excess extracellular stannous ion and prevent extra
cellular reduction of 99mTc pertechnetate. Labeling occurs
when 99mTc pertechnetate is added, followed by a 20-minute
incubation before reinjection of labeled cells.
4. The in vivo method is simplest and least costly, but has the
lowest labeling efficiency. The in vitro kit method
(UltraTag) has the highest labeling efficiency but requires
more time, technologist effort, and cost.
1. Describe and explain the processing performed on this equilibrium gated RVG or MUGA study.
2. How are the regions of interest (ROIs) selected?
3. List the nuclear medicine techniques by which left ventricular function can be assessed.
4. Provide the equation for determination of LVEF.
Cardiac: Calculation of LVEF for RVG (MUGA)
1. Left anterior oblique end-diastolic and end-systolic images
show left ventricular and background (bkg) ROIs drawn
on computer for calculation of the LVEF.
2. Acquisition in the left anterior oblique (LAO) view with
greatest separation of the left and right ventricle. ROI for
the left ventricle at end-systole, at end-diastole, and for
adjacent background.
3. Equilibrium gated blood pool (RVG); first-pass radionuclide
ventriculography; gated perfusion SPECT.
4. LVEF = end-diastolic counts — end-systolic counts/
end-diastolic counts (corrected for bkg counts).
Radionuclide planar gated blood pool study. Sequential gated image frames are shown.
1. Estimate the left ventricular ejection fraction (LVEF) based on the submitted images and explain the decreased
intensity of image No. 16.
2. Discuss the importance of patient positioning on calculation of the LVEF.
3. List factors that may result in reduced accuracy of the LVEF calculation.
4. Describe the effect on the LVEF if (A) no background is subtracted; (B) a background region is used that includes
the spleen.
Cardiovascular System: RVG/MUGA
1. LVEF appears normal (>55%). End-systolic at Frame 8.
Frame 16 shows decreased intensity compared with other
frames, resulting from variability in the patient's heart rate,
e.g., frequent PVCs.
2. The left anterior oblique (LAO) position selected is that
which provides the best separation of the left and right
ventricles, approximately a 45-degree LAO view, but varies
depending on the patient's anatomy (best septal view).
3. Patient-related factors: arrhythmia, inability to gait, suboptimal
RBC labeling, e.g., concomitant drugs. Techniquerelated:
poor LAO positioning, suboptimal RBC labeling;
incorrect ROI for left ventricle or background.
4. A, Falsely low; B, falsely high.
A 35-year-old man with increasing dyspnea was referred for ventilation-perfusion (V/Q) study. The chest film was
clear of infiltrate, mass, or pleural disease.
1. Name the three phases of a 133Xe ventilation scan.
2. Describe the phases.
3. Describe the findings on the ventilation and perfusion scans.
4. Provide an interpretation and offer a diagnosis for the underlying disease.
Pulmonary System: Emphysema Caused
by o^-Antitrypsin Deficiency
1. Single breath or wash-in, equilibrium, and washout phases.
2. Single breath: patient breathes in and holds a single maxi
mum deep inspiration while a 100,000-count image is
acquired. Equilibrium: patient breathes a mixture of air
and xenon while serial images are obtained every 60 to 90
seconds for 3 minutes. Washout: patient breathes room air
and exhales xenon while serial images are obtained.
3. Ventilation: nonuniform in the upper lung zones bilater
ally. Initially near absent at the bases. As upper lobes wash
out, xenon fills and is retained in both bases indicating
severe air trapping. Perfusion: heterogeneous to both
upper lung zones that match the early ventilation images.
The extensive perfusion abnormalities in both lower lung
zones are matched with areas of washout air trapping.
4. Low probability for pulmonary embolism, arantitrypsin
A 64-year-old man has recent onset of shortness of breath. The chest x-ray was clear.
1. Describe the image findings (A, perfusion; B, ventilation) and give an interpretation.
2. What is the ventilation study radiopharmaceutical, and what is its mechanism of distribution? What are the likely
reasons for their appearance on this study?
3. Is the ventilation or perfusion study usually performed first and why?
4. What is another commonly used ventilation radiopharmaceutical that could be used, and what are the advantages
and disadvantages?
Pulmonary System: 99mTc DTPA Ventilation
Study with Aerosol Clumping
1. Multiple perfusion defects in upper and lower lung fields.
Many appear segmental, e.g., the lateral basal of the right
lower lobe, superior segment of the left lower lobe. Venti
lation study shows extensive diffuse "clumping" within the
airways throughout both lung fields making determination
of matching or mismatching difficult. The study was inter
preted as intermediate probability since the ventilation
study could not be interpreted; however, the segmental
perfusion defect pattern is suspicious for embolus.
2. 99mTc DTPA aerosol particles (0.1 to 0.5 \x,m in size) nor
mally distribute on first impact within the alveoli. With
airway turbulence, e.g., asthma or COPD, particles impact
proximally within bronchi and appear as focal hot spots.
3. 99mTc DTPA aerosol ventilation study usually is performed
first. The patient breathes in less than 1 mCi at tidal vol
ume until an adequate count rate is obtained (3,000
counts/sec). The sixfold larger 99mTc MAA perfusion dose
(5-mCi) overwhelms the retained ventilation dose, allow
ing for two consecutive 99mTc studies.
4. 133Xe, an inert gas, is advantageous for patients with
COPD and asthma. Delayed filling and clearance (air
trapping) in regions of obstructive disease can be seen.
Disadvantage: only posterior views are possible because of
rapid exhalation.
A 54-year-old man with known cardiopulmonary disease complains of increasing dyspnea. A, Chest radiograph;
B, perfusion scan; C, ventilation scan.
1. What are the scintigraphic findings and interpretation?
2. What is the likelihood of pulmonary embolus in this patient?
3. What is the likelihood of pulmonary embolus in a patient with a normal scan?
4. How are perfusion defects classified as to size?
Pulmonary System: Low-Probability
Ventilation-Perfusion Scan
1. Bilateral inhomogeneous distribution. Matched perfusion
and ventilation abnormalities throughout the upper and
lower lobes, especially in the right lower lobe basal seg
ments. Minimal atelectasis in the lower lobes on chest
x-ray. Low probability for pulmonary embolus.
2. Less than 20%.
3. Less than 1%.
4. Large (segmental): greater than 75% of a segment.
Moderate (subsegmental): 25% to 75% of a segment.
Small (small subsegmental): less than 25% of a segment.
A 29-year-old pregnant woman has a history of asthma and recent onset of dyspnea.
1. Is any patient preparation indicated?
2. Would the patient's pregnancy change the V/Q protocol?
3. Describe the perfusion (A) and ventilation (B) images and radiograph findings (C).
4. Give your interpretation of the study.
Pulmonary System: Intermediate Probability and Pregnancy
1. Bronchodilator therapy before V/Q study as an asthmatic therapeutic trial.
2. Pulmonary emboli are life threatening to the patient and
fetus. The radiation dose to the patient and fetus is low (less than 2 rads). The benefit/risk ratio is high. No change
in procedure is required. In young, nonsmoking patients without cardiopulmonary disease, one might reduce the dose, conduct only a perfusion study, or both.
3. Hypoperfusion of the left lower lobe, except the superior segment. Better ventilation than perfusion with mismatch
ing, in the anterior basal and part of the lateral basal segments. No ventilation in the posterior basal and part of
the lateral basal. Costophrenic angle loss seen in left lateral and LPO views. Radiograph: atelectasis/infiltrate with elevation of the left diaphragm.
4. Intermediate probability for pulmonary embolus. One
large/one moderate segmental mismatch and one large and
one moderate segmental match corresponding to the x-ray
Two patients (A and B) with similar histories of a soft tissue infection overlying the tibia. 99mTc HM-PAO leukocyte
studies were ordered to confirm or exclude underlying osteomyelitis.
1. Would a bone scan be useful as the initial study in these cases?
2. When would a bone marrow study with 99mTc sulfur colloid be useful in this clinical setting?
3. Would an ' "In oxine leukocyte study or 67Ga study be preferable?
4. Describe the findings. What are the diagnoses?
Infection and Inflammation: 99mTc HM-PAO
Leukocytes and Osteomyelitis
1. A negative bone scan rules out osteomyelitis with a high
degree of certainty.
2. A bone marrow study can improve the specificity of a
leukocyte study if there is displaced normal marrow
(orthopedic hardware). This is most helpful in the hips
and knees.
3. ' "In leukocytes can make the same diagnosis. The superior
imaging resolution of 99mTc HM-PAO often better differ
entiates soft tissue and bone infection. 67Ga is less specific
because increased uptake occurs with bone remodeling
from any cause.
4. Patient A: soft tissue uptake. No bone uptake rules out
osteomyelitis; consistent with cellulitis. Patient B: soft tis
sue and bone localization consistent with osteomyelitis.
A 49-year-old man was referred for 99mTc HM-PAO leukocyte study to locate the source of Staphylococcus aureus sepsis.
1. What are the scintigraphic findings?
2. What is your interpretation of the study?
3. What are the most common causes for false-positive radiolabeled leukocyte studies?
4. What is the optimal imaging period for 67Ga, ulIn oxine leukocytes, 99mTc HM-PAO leukocytes for infection
Infection and Inflammation: 99mTc HM-PAO Leukocytes-free 99mTc pertechnetate
1. Activity in the salivary glands, thyroid, stomach, bowel,
and bladder.
2. Free 99raTc pertechnetate. Nondiagnostic study.
3. Gastrointestinal bleeding, swallowed leukocytes from
oropharyngeal, esophageal, or lung inflammation/
infection, accessory spleen, uninfected postoperative
surgical wounds, intestinal stomas, and catheter sites.
3. 67Ga, 48 hours; nlIn oxine leukocytes, 24 hours; 99mTc
HM-PAO leukocytes, 1 to 4 hours.
A 25-year-old man has fever and abdominal pain. 99mTc HM-PAO-labeled leukocyte images.
1. Which leukocytes are labeled with the two radiopharmaceuticals used for leukocyte scans?
2. What is the explanation for the prominent skeletal uptake?
3. What is the optimal imaging time for ' "In oxine-labeled leukocytes and 99mTc HM-PAO leukocytes?
4. Give an image interpretation and diagnosis in this case.
Infection and Inflammation: Intraabdominal Abscess
1. 99mTc HM-PAO binds only to neutrophils. nlIn oxine
binds to mixed leukocytes.
2. Normal bone marrow distribution of the radiolabeled
3. Abdominal imaging: 99mTc HM-PAO images are acquired
at 1 to 2 hours because hepatobiliary, intestinal, and renal
clearance occurs subsequently, complicating interpretation.
Extremity imaging: 2 to 6 hours. nlIn leukocytes: 24
hours. Four-hour imaging for inflammatory bowel disease
because sloughing of intestinal mucosa leukocytes may
occur and 24-hour may be misleading.
4. Infection in the right lower quadrant overlying the sacroiliac
joint in the anterior view and lateral right of the spine.
The patient had a perforated appendix.
An 8-year-old girl with juvenile rheumatoid arthritis and persistent fever after resolution of recent pneumonia. She has
no current symptoms of arthritis.
1. Describe the findings on 67Ga sequential coronal SPECT chest images (A) and a selected enlarged image (B). Image
intensity is high. What is the differential diagnosis?
2. What is the advantage of 67Ga over indium- or technetium-labeled leukocytes for fever of unknown origin?
3. What is the target organ (highest radiation absorbed dose) for 67Ga?
4. Which pulmonary infections or inflammatory diseases show increased 67Ga uptake?
Infection and Inflammation: Pericarditis—67Ga
1. Abnormal uptake in myocardium, pericardium, or bothconsistent
with pericarditis or myocarditis. The patient developed a pericardial friction rub the day after the 67Ga
scan. Incidental note of normal liver uptake and transverse
and left colon clearance.
2. 67Ga shows uptake not only with inflammation and infec
tion, but also in tumors that can sometimes be the cause of
persistent fever, e.g., lymphoma.
3. Large bowel, approximately 4.5 rads.
4. Most pulmonary inflammatory and infectious diseases.
Uptake is nonspecific, although the pattern of uptake and
the clinical setting, e.g., AIDS, may be helpful in deter
mining the differential diagnosis.
A, 70-year-old man with recent onset of flushing, diarrhea, elevated 5-hydroxyindoleacetic acid (5-HIAA), and a diag
nosis of carcinoid syndrome. B, 56-year-old patient with past history of medullary carcinoma of the thyroid and recent
increase in serum calcitonin levels.
1. Provide the mechanism of uptake of" In pentetreotide (OctreoScan).
2. List the category of tumors for which this radiopharmaceutical is particularly useful.
3. Describe the image findings on these two studies: A (abdominal/pelvis view) and B (chest views), and give your
4. Name the organs that normally have greatest uptake of the radiopharmaceutical.
Oncology: Neuroectodermal Tumors
1. Peptide analogue of somatostatin and octreotide. Binds to
tumors with somatostatin receptors.
2. Neuroendocrine tumors.
3. A, Multiple metastases to both lobes of the liver. Two large
foci and one small focus of uptake consistent with paraaortic
tumor adenopathy. Possible small tumor in right hilum
(confirmed by later CT). B, Prominent irregular uptake in
the anterior mediastinum and focal uptake in the left
lower lung posteriorly.
4. Kidneys and spleen.
Three patients in images A, B, and Chave whole body 67Ga scans.
1. What is the normal distribution of 67Ga?
2. Which studies show postchemotherapy changes? What are the findings?
3. What are other causes of 67Ga lung uptake?
4. Which study shows an altered distribution of the radiopharmaceutical? Causes?
Oncology: Postchemotherapy 67Ga Findings
1. Greatest to least uptake: liver, bone/bone marrow, spleen,
kidney (excretion pathway), salivary and lacrimal glands.
2. B, Thymus uptake is not an uncommon nonpathological
finding after chemotherapy. C, Diffuse pulmonary uptake
is consistent with pulmonary toxicity, e.g., bleomycininduced
lung disease.
3. Gallium-avid tumor, inflammation, and infection.
4. A, Decreased hepatic and marrow uptake. Causes: recent
MRI gadolinium contrast study, very recent chemotherapy,
or iron saturation, e.g., multiple transfusions.
A patient with malignant B-cell lymphoma. Initial FDG-PET study (A) shows tumor above and below the diaphragm.
Postchemotherapy CT shows a residual abdominal mass. Posttherapy FDG-PET (B).
1. Is remission complete or partial based on the CT and subsequent PET study?
2. What are the limitations of CT for staging and restaging of disease in patients with lymphoma?
3. List imaging limitations of 67Ga.
4. What are the advantages of 18F FDG-PET compared with 67Ga?
Oncology: 18F FDG-PET—Lymphoma
1. The CT scan is indeterminate, but FDG-PET demonstrates
a complete response.
2. CT assessment of tumor response is based on a decrease in
the size of the mass or complete resolution. However, posttherapy
residual masses are common and CT cannot dif
ferentiate residual tumor from posttherapy fibrosis and
3. Multiple high-energy photopeaks: 185, 300, 394 resulting
in poor image resolution; frequent need for delayed imag
ing (48 to 72 hours and sometimes 5 to 7 days) to allow
for bowel clearance.
4. Study completed 2 hours after injection. FDG-PET targetto-
background ratio is higher and image quality superior
to 67Ga. Usually little bowel activity with FDG. Data are
limited, but consensus is that FDG is superior to 67Ga.
A 33-year-old male smoker has a poorly defined right mid-lung density on chest x-ray (A, marked). CT reported a
1.5-cm lesion with infiltrative margins in the superior segment of the RLL (B) but no other abnormality.
1. Describe the ' 8F FDG-PET scan findings (C). Sequential coronal slices are shown.
2. How has this PET scan affected the patient's preoperative staging?
3. What is the overall accuracy of CT and MR for preoperative staging of lung cancer?
4. What is the overall accuracy of 18F FDG-PET for preoperative lung cancer staging?
Oncology: 18F FDG-PET—Lung Cancer Staging
1. Focal increased uptake corresponding to the nodule on CT
(frames 358-370). In addition, abnormal uptake is seen in
the right and left paratracheal regions, the right and left
hilum, and the mediastinum, all consistent with tumor
2. 18F FDG-PET has preoperatively upstaged the patient,
who is no longer a surgical candidate.
3. Approximately 65%.
4. Approximately 85%.
A 69-year-old man has a history of colorectal carcinoma and surgical resection. The carcinoembryonic antigen (CEA)
level is increasing and the CT scan shows a new 2.3-cm lesion in the right lobe of the liver.
1. FDG-PET scan (A) was then obtained. What are the findings?
2. Why was the FDG-PET scan ordered?
3. What are clinical indications for FDG-PET in colorectal carcinoma?
4. FDG-PET scan (B) was performed 6 months after resection of the liver lesion. Describe the findings.
Oncology: 18F FDG-PET—Colorectal Cancer Metastatic to Liver
1. Increased uptake consistent with tumor in the liver corre
sponding to the reported CT mass. No other liver lesions
or metastases are seen elsewhere in the whole body scan.
2. Surgical resection is planned. The preoperative FDG-PET
scan is used to determine the presence of any other metas
tases in the liver or elsewhere in the body that might change
the surgical approach or make the patient inoperable.
3. (1) Increasing serum CEA levels with normal conventional
imaging, (2) equivocal lesion with conventional imaging,
and (3) preoperative staging before curative resection.
4. Negative scan. No evidence of tumor.
A 54-year-old woman with bronchogenic carcinoma metastatic to the brain recently underwent stereotactic radiosurgery
for a lesion in the left temporoparietal region. MRI could not differentiate posttherapy changes from viable
tumor (A).
1. Give the relative accuracy of FDG-PET versus CT or MRI for diagnosing malignant tumor in the brain.
2. What is the relative accuracy of FDG-PET versus CT/MRI for differentiating recurrent or persistent tumor from
postradiation necrosis?
3. Describe the image findings and interpret the transaxial images (B) of FDG-PET of the brain.
4. List single photon radiotracers used for brain imaging and describe the expected findings.
Oncology: 18F FDG-PET—Bronchogenic Cancer
Metastatic to Brain
1. CT and MRI are more sensitive for tumor detection.
Normal brain uses only glucose for metabolism and has
higher uptake than any other organ. This results in high
background that can make tumor detection difficult.
2. FDG-PET is more accurate than CT or MRI for deter
mining whether posttherapy changes are the result of
residual/recurrent tumor or radiation necrosis.
3. Focal increased uptake in the left temporoparietal region
that correlates with the lesion on MRI. This is consistent
with viable residual or recurrent tumor.
4. 2O1T1 and 99mTc sestamibi have increased uptake in
tumors. Tumors usually are cold on 99mTc HM-PAO and
A 35-year-old-man with AIDS has a new intracranial abnormality on MRI (A and B) of uncertain origin. A SPECT
study (Cl, coronal; C2, sagittal; C3, transverse) was ordered to assist in the differential diagnosis.
1. What is the radiopharmaceutical?
2. What is the differential diagnosis before the SPECT study?
3. What is the likely diagnosis after the radionuclide study?
4. What is the accuracy of the radionuclide method?
Oncology: 201TI—Intracranial Lymphoma
1. 201Tl was used. 99mTc sestamibi also can be used; however,
it is taken up by the choroid plexus and could pose diag
nostic problems in some cases.
2. Tumor, particularly lymphoma, versus infection, usually
toxoplasmosis, or other opportunistic infections, e.g.,
cytomegalic inclusion virus, herpes simplex, Cryptococcus.
3. Malignant lymphoma.
4. Approximately 90% sensitivity for tumor. False-positive
rate of less than 10%.
A 49-year-old woman was referred for breast lymphoscintigraphy after recent biopsy of a right breast mass and the di
agnosis of breast cancer.
1. What is the implication of axillary node involvement in breast cancer?
2. What is a sentinel node?
3. What is the purpose of sentinel node biopsy?
4. What is the radiopharmaceutical used, and how is the study performed?
Oncology: Breast Cancer Lymphoscintigraphy
1. The 5-year survival rate for breast cancer decreases with axil
lary node involvement. Adjuvant chemotherapy is indicated.
2. A sentinel node is the first node drained by the lymphatics
in a nodal basin.
3. If the sentinel node biopsy is tumor negative, no axillary
dissection is needed. If positive, axillary dissection is
4. The pharmaceutical often used is filtered 99mTc sulfur col
loid. It is injected around the lesion or biopsy site. Imag
ing usually is performed. At surgery a gamma probe is
used to help locate the sentinel node.
Sentinel node lymphoscintigraphy was performed for malignant melanoma in the mid-left posterior thorax. Oneminute
posterior images (A) are followed by anterior and posterior static images with a cobalt transmission source
placed behind the patient for body contour (B). A lead shield was placed over the injection site on the static posterior
images (appears cold).
1. What is the radiopharmaceutical commonly used and what is the rationale for its use?
2. Describe the study findings.
3. What is the normal drainage of a mid posterior chest or flank lesion?
4. How are patients with melanoma selected for lymphoscintigraphy?
Oncology: Melanoma Lymphoscintigraphy
1. Filtered 99mTc sulfur colloid particles, 0.1 to 0.22 |xm in
size, are injected intradermally, taken up by the lymphat
ics, and demonstrate lymphatic channels and nodes.
2. One-minute dynamic images: drainage to the right axilla
through two separate lymphatic channels, also drains to
the left axilla. Nodal uptake in the right axilla is seen on
the static posterior view. The anterior view shows two right
sentinel nodes and one on the left.
3. Drainage is unpredictable, and may drain to either axillary
or to inguinal regions.
4. Prognosis is determined by lesion depth. Those less than
0.76 mm are low risk and rarely metastasize; those deeper
than 4 mm often metastasize. Patients with intermediate thickness
lesions are referred for lymphoscintigraphy and sentinel node biopsy.
A 43-year-old woman was hospitalized with abdominal pain, nausea, and vomiting that started 24 hours before
1. What are the cholescintigraphic findings?
2. What clinical information would be helpful to correctly interpret the study?
3. What is the differential diagnosis?
4. What would you do next?
Hepatobiliary System: Delayed Biliary-to- Bowel Transit
1. Normal gallbladder filling and secretion into biliary ducts;
however, no clearance of radiotracer from the common
duct or biliary-to-bowel transit by 60 minutes.
2. Is the patient receiving narcotics? Was sincalide (CCK)
given before the study?
3. Partial common duct obstruction, functional obstruction
caused by sincalide administered before the study, recent
narcotic administration, or normal variation.
4. Obtain delayed images or give CCK. The latter would give
the answer more promptly.
A 63-year-old woman has been hospitalized for 9 days with multiple serious medical problems and is receiving hyperalimentation.
Now acute abdominal pain has developed. She has been referred for cholescintigraphy to rule out acute
cholecystitis. A, 60-minute cholescintigraphy. B, Additional 30-minute images after administration of morphine.
1. What is the relative accuracy of cholescintigraphy in this patient's clinical setting?
2. Describe the cholescintigraphic findings.
3. What is the clinical significance of these findings?
4. What pathological condition is likely?
Hepatobiliary System: RIM Sign
1. Increased incidence of false-positive study results in
patients who have been fasting more than 24 hours, those
receiving hyperalimentation, or those with concomitant
serious illness.
2. Nonvisualization of the gallbladder after 60 minutes. After
morphine administration no filling of the gallbladder
occurs. Increased uptake is seen in the region of the gall
bladder fossa, which persists after most of the liver has
washed out (RIM sign).
3. Nonvisualization of the gallbladder after morphine admin
istration is consistent with acute cholecystitis, but the
specificity is reduced somewhat in this clinical setting
(hyperalimentation). The RIM sign is very specific for
acute cholecystitis and confirms the diagnosis.
4. The RIM sign indicates severe acute cholecystitis, which is
associated with an increased incidence of gallbladder gan
grene and perforation.
A 50-year-old woman has acute onset of abdominal pain of 4 hours' duration. Ultrasonography results are normal.
1. What are the cholescintigraphic findings and the diagnosis?
2. Differentiate the terms surgicaljaundice, biliary obstruction, and bile duct dilation.
3. Differentiate the 99mTc IDA findings of high- and low-grade biliary obstruction.
4. How do the cholescintigraphic findings of hepatic insufficiency differ from this case?
Hepatobiliary System: High-Grade Biliary
1. Prompt hepatic uptake, no excretion into the biliary tract,
consistent with high-grade common duct obstruction.
Cholestatic jaundice, e.g., drug reaction, may look similar.
2. Obstruction may occur without jaundice. Jaundice is a late
manifestation. Obstruction does not always result in ductal
dilation. Dilation can be present without obstruction.
3. High-grade: hepatic uptake, no biliary clearance. Lowgrade:
secretion into biliary ducts, delayed clearance from
the biliary ducts, and delayed biliary-to-bowel transit.
4. Hepatic insufficiency: delayed liver uptake and delayed
hepatic and background clearance, often delayed biliaryto-
bowel transit.
A 50-year-old man with several months of abdominal discomfort and jaundice.
1. Describe the cholescintigraphic findings.
2. What is the differential diagnosis at 60 minutes?
3. How have delayed images helped make the diagnosis?
4. What are the possible FDA-approved radiopharmaceuticals and their alternative route of excretion?
Hepatobiliary System: Hepatic Insufficiency
1. Poor hepatic function: delayed blood pool (heart and great
vessels) and background clearance, no secretion into biliary
ducts at 60 minutes. Delayed images show very late filling
of the gallbladder and biliary-to-bowel transit by 24 hours.
2. Hepatic insufficiency, biliary obstruction with secondary
hepatic insufficiency.
3. Delayed images show no radiotracer retention within the
biliary ducts and biliary-to-bowel transit, ruling out
4. 99roTc mebrofenin or bromotriethyl minodiacetic acid
(IDA; Choletec) or 99mTc disofenin or DISIDA
(Hepatolite). Renal excretion.
A 39-year-old woman with abdominal pain; history of cholecystectomy. Results of real-time ultrasonography are normal.
1. Describe the cholescintigraphic findings.
2. Give the differential diagnosis at 60 minutes.
3. Give the diagnosis at 120 minutes.
4. What is an alternative method for making the diagnosis?
Hepatobiliary System: Acute Cholecystitis
and Biliary Obstruction
1. Nonfilling of the gallbladder, prominent retained activity
in the common duct at 60 minutes, with definite biliaryto-
bowel clearance. Continuing biliary-to-bowel transit at
120 minutes, however, increased retention in the commonduct.
Minor enterogastric reflux.
2. Partial biliary obstruction, hyptonic sphincter of Oddi
(normal variation, CCK given before the study, chronic
3. Very suspicious for partial common duct obstruction.
4. Administer CCK.
Both patients are 4 weeks old (A and 5). They have hyperbilirubinemia and were referred to rule out biliary atresia.
1. What patient preparation is required before the cholescintigraphic study?
2. What is the differential diagnosis of hyperbilirubinemia in this age group?
3. What are the scintigraphic findings on these studies and your interpretations?
4. What is the accuracy of cholescintigraphy to diagnose biliary atresia?
Hepatobiliary System: Biliary Atresia
1. Phenobarbital, 5 mg/kg/day for 3 to 5 days before the study.
2. Inflammatory, infectious, and metabolic causes for neona
tal hepatitis and biliary atresia.
3. A, Delayed blood pool clearance (note heart) as a result of
hepatic insufficiency. Biliary clearance at 50 minutes and
increasing through 120 minutes. Note the medial edge of
the gallbladder (image intensity set high to see bowel
activity). B, Good liver function. No secretion into biliary
ducts during the initial 120 minutes or at 5 and 24 hours.
Case B is consistent with biliary atresia, case A with neona
tal hepatitis.
4. Sensitivity 97%, specificity 82%.
A 46-year-old woman had two different SPECT radionuclide liver studies (A and B). Comparable selected transaxial
slices are shown for the two studies.
1. Name the two radiopharmaceuticals used.
2. What are the scintigraphic findings?
3. What is the differential diagnosis of scan B alone?
4. What is the diagnosis in this patient?
Hepatobiliary System: Cavernous Hemangioma
of the Liver
1. A, 99mTc-labeled RBC liver study. B, »Tc sulfur colloid
2. Increased uptake on the 99mTc-labeled RBC study in the
same region where a defect (photopenic region) is seen on
the 99mTc sulfur colloid study.
3. Any benign or malignant mass lesion of rhe liver.
4. Cavernous hemangioma of the liver.
This patient has a history of idiopathic thrombocytopenic purpura and prior splenectomy, and now has clinical evidence
of recurrent disease. Anterior, posterior (A), and left lateral view of a radionuclide scan (B) with the intensity set high.
1. What is the radiopharmaceutical?
2. What is the likely purpose of the study?
3. Could other studies be used to make the same diagnosis?
4. How would you interpret the study?
Hepatobiliary System: Splenic Remnant
1. 99raTc sulfur colloid.
2. To detect a splenic remnant, splenosis, or accessory splenic
3. Heat or chemically damaged 99mTc RBC study.
4. Positive for the presence of a splenic remnant.
Bright red blood per rectum. No prior history.
1. What radionuclide study is this? Describe the scintigraphic findings.
2. Provide an accurate location for the findings.
3. Name another method of image review that should be used.
4. Provide the differential diagnosis.
Gastrointestinal System: Gastrointestinal
Bleeding as a Result of Angiodysplasia
1. 99mTc-Iabeled erythrocyte study. Abnormal focal uptake
appearing simultaneously at two sites in the right abdo
men, increasing in intensity and changing in pattern with
2. Cecum and ascending colon.
3. Review images on a computer monitor in cinematic mode.
4. Acute bleeding due to angiodysplasia, diverticula, neoplasm,
inflammatory bowel disease, and ischemia.
Recent bright red blood per rectum and low hematocrit.
1. Based on the history, what nuclear scans would be appropriate?
2. What information from the history is critical to determine the appropriate time to perform the examination?
3. Name the radiopharmaceutical used for this examination.
4. Describe the scintigraphic findings (first six images are blood flow, last two are delayed statics).
Gastrointestinal System: 99mTc RBC Scan— Axillobifemoral Bypass Craft
1. 99mTc-labeled red blood cells or 99mTc sulfur colloid.
2. Evidence of current or recent gastrointestinal bleeding.
3. 99mTc-labeled RBCs.
4. The vascular flow and delayed static images show no active
gastrointestinal bleeding. Labeled red cells are shown in a
tubular shape in the right abdomen that connects after a Y bifurcation to the two iliac vessels as a result of an axillobifemoral vascular bypass graft. The patient has prominent splenomegaly.
Two patients (A and B) were referred for a radionuclide gastrointestinal bleeding study.
1. What is the radiopharmaceutical used in these studies?
2. Describe the image findings in both studies.
3. Interpret the two studies.
4. Which method of radiolabeling of RBCs has the highest labeling efficiency?
Gastrointestinal System: 99mTc RBC-Free
Pertechnetate versus Gastric Bleeding
1. 99raTc pertechnetate labeled to RBCs.
2. In both studies the stomach visualizes promptly. The chest
and neck image shows thyroid and salivary uptake in study
A (15-minute image) but not in study B (120-minute
3. A, Free 99mTc pertechnetate. Negative for gastrointestinal
bleeding. B, Active bleeding originating from the stomach.
4. In vitro.
A patient has a seizure disorder unresponsive to medical therapy and is being considered for surgical treatment.
1. Describe the image finding on these coronal 18F FDG-PET slices.
2. What is the differential diagnosis of this image finding if no history was available?
3. What is the probable seizure focus site?
4. What is the utility of PET or SPECT in seizure disorders?
Central Nervous System: Seizure Disorder
1. Decreased metabolism in the left temporal lobe.
2. Temporal lobe infarct, benign mass or low-grade tumor,
postradiation therapy changes, interictal left temporal lobe
seizure focus.
3. Interictal seizure focus in the left temporal lobe.
4. Confirmation of the location of the seizure focus in a can
didate for temporal lobectomy. Study is an alternative to
surgical depth electrode placement.
A 55-year-old man has had worsening dementia over 10 months.
1. Give a clinical differential diagnosis for dementia.
2. How can SPECT or PET aid in this differential diagnosis?
3. Describe the 18F FDG-PET findings on the reconstructed three-dimensional volume display.
4. What is the diagnosis and with what degree of certainty?
Central Nervous System: Alzheimer's Disease
1. Multiinfarct, Alzheimer's disease, AIDS-related, substance
abuse, alcoholism, Parkinson's, Pick's, Creutzfeldt-Jacob
disease, depression, metabolic.
2. Diagnostic patterns using 9>mTc HM-PAO/ECD SPECT
and FDG-PET: multiinfarct dementia, Alzheimer's disease,
frontal lobe dementias, e.g., Pick's disease.
3. Hypometabolism (decreased FDG uptake) of the posterior
parietal and temporal lobes bilaterally and to a lesser extent
the frontal lobes. Note persistent metabolism of sensorimotor
4. Alzheimer's disease; greater than 80% certainly.
A 55-year-old man has increasing dementia. Recently he had a normal MRI. Sagittal SPECT sections are submitted.
1. List the most common causes of dementia in the elderly.
2. Describe the mechanism of uptake of the radiopharmaceutical used.
3. What causes of dementia are associated with characteristic SPECT perfusion patterns?
4. Describe the findings and the most likely diagnosis.
Central Nervous System: Pick's Disease
1. Alzheimer's disease, multiinfarct, late-stage Parkinson's dis
ease, metabolic, drug-related, depression.
2. The lipophilic 99mTc HM-PAO or ECD agents cross the
intact blood-brain barrier and have rapid intracellular
uptake in proportion to cerebral blood flow. They are fixed
intracellularly. Subsequent imaging provide a "snapshot" of
the blood flow pattern at the time of the injection.
3. Alzheimer's, multiinfarct dementia, Pick's disease.
4. Decreased blood flow in the frontal cortex bilaterally as a
result of frontal lobe dementia, e.g., Pick's disease.
A 25-year-old woman had a kidney transplant 7 days earlier.
1. What are the scintigraphic findings of this 99mTc MAG3 study?
2. What is the most likely diagnosis?
3. What are the usual associated clinical symptoms and findings?
4. How is the final diagnosis established?
Genitourinary System: Acute Renal Transplant
1. Very decreased and delayed blood flow and poor trans
plant function.
2. Acute rejection.
3. Fever, transplant tenderness and enlargement, decreased
urinary output, and rising serum creatinine level.
4. Biopsy.
A 59-year-old man admitted to the hospital with pneumonia, elevated serum creatinine level, and no known renal
1. In what projection are renal studies acquired? Name the structures seen on the flow study (A).
2. What are the findings on the postflow dynamic 30-minute study (B)? What is the diagnosis?
3. What three general causes of renal failure can the radionuclide study help diagnose?
4. Name the appropriate radiopharmaceutical in this clinical setting?
Genitourinary System: Renal Insufficiency—Small Kidneys, Poor Function
1. Posterior. Right ventricle, lungs, left ventricle, aorta, spleen (not left kidney). The kidneys are very poorly visualized on
this flow study, consistent with poor blood flow.
2. Bilaterally small kidneys. Extremely poor renal function. Clearance into the bladder. Diagnosis of chronic renal insufficiency secondary to parenchymal disease.
3. The radionuclide renogram can differentiate prerenal, intrarenal (parenchymal), and postrenal causes.
4. 9')mTcMAG3.
A 30-year-old man has poorly controlled and accelerating hypertension. Baseline study without captopril (A) and
99mTc MAG3 renal studies with captopril (B) are shown.
1. What is the rationale and physiological mechanism for the captopril renal study?
2. What are the scintigraphic and time-activity curve findings and diagnosis?
3. Could 13II hippuran or 99mTc DPTA have been used instead?
4. What is the accuracy of captopril renography?
Genitourinary System: Captopril Renography
1. With renal artery stenosis, glomerular perfusion decreases
and glomerular filtration rate (GFR) drops. Renin released
from the juxtaglomemlar apparatus converts angiotensin I
to angiotensin II. Angiotensin II causes vasoconstriction of
the glomerular efferent arterioles, raising filtration pressure
and maintaining GFR. An angiotensin-converting enzyme
(ACE) inhibitor, e.g., captopril, blocks conversion of
angiotensin I to II, resulting in a decrease in GFR.
2. The right kidney is small but with good function. With
captopril cortical retention persists, consistent with renindependent
renovascular hypertension of the right kidney.
This is confirmed by the renal cortical time-activity curves.
3. Yes. The accuracy of 13II hippuran, 99mTc DTPA, and
99mTc MAG3 are similar.
4. Sensitivity, 90%; specificity, 95%. Sensitivity is less for
detection of renin-dependent hypertension if the patient
has been taking an ACE inhibitor chronically or has renal
A 7-year-old with hydronephrosis demonstrated on ultrasound examination. No prior history.
1. Based on the history, list the preferred radiopharmaceutical(s) for this study.
2. Would a renal cortical agent be appropriate?
3. Describe the initial findings (A) and following diuretic administration (B and C).
4. List the differential diagnosis and most likely diagnosis.
Primary Megaureter
1. 99raTc MAG3 or 99mTc DTPA.
2. No, both 99mTc dimercaptosuccinic acid (DMSA) or
99mTc glucoheptonate fix to the renal cortex.
3. Left kidney excretes promptly into collecting system with
retention in prominent pelvis and ureter. Prominent dila
tion distally. After diuretic: prompt clearance of the left
collecting system by visual and quantitative assessment.
Normal right kidney.
4. Dilated nonobstructed left ureter. Possible causes: vesicoureteral
reflux, corrected ureteral vesicle junction obstruc
tion, and primary megaureter; the latter is more likely
based on the prominent dilatation of the distal ureter.
A 6-year-old girl has recurrent and recent urinary tract infections. A, 99mTc DMSA SPECT renal study. B, A repeat
study 6 months later (comparable coronal slices).
1. What is the mechanism of uptake of 99mTc DMSA?
2. What are the most common indications for a 99mTc DMSA study?
3. What are the scintigraphic SPECT findings and what is the diagnosis? What would have been the diagnosis if the
second study (B) looked similar to the first study (A)?
4. What is the clinical importance of differentiating upper and lower tract infection?
Genitourinary System: Pyelonephritis and
99mTc DMSA
1. Forty percent of 99mTc DMSA binds and fixes to function
ing proximal cortical renal tubules.
2. Diagnosis of pyelonephritis or cortical scarring.
3. Decreased uptake in the lower half of the right kidney on
initial imaging (A). Repeat SPECT show normalization of
uptake. A, Pyelonephritis; B, renal cortical scarring.
4. "'"Tc DMSA in the early stages of infection is the best
predictor of renal sequelae. Identification of pyelonephritis
will increase the duration of antibiotic therapy.
A 39-year-old woman has a 3-year history of hyperthyroidism. 123I thyroid scans were performed each year, shown
from left to right.
1. Describe the scintigraphic findings.
2. Give the diagnosis.
3. What treatment options are appropriate for this patient?
4. What would you expect the radioactive iodine thyroid uptake to be?
Endocrine System: Toxic Autonomous Thyroid Nodule
1. Hot nodule in the mid-right lobe of the thyroid, with increasing suppression of the remaining gland at each successive year.
2. Toxic autonomous thyroid nodule.
3. Surgery and radioactive I3II are the usual methods of treat
ment. Therapy with propylthiouracil (PTU) or methimazole
(Tapazole) sometimes is used as initial treatment.
4. The radioactive iodine uptake may be moderately elevated,
but it often is in the normal range. Normal 24-hour
uptake is 10% to 30%.
99mTc pertechnetate scan in a 3-year-old child with a subiingual mass. Patient is euthyroid.
1. What is the mechanism of 99mTc pertechnetate and 123I sodium iodide uptake?
2. What is the advantage of 99mTc pertechnetate over 123I in this patient?
3. Describe the scintigraphic findings.
4. What is the diagnosis?
Endocrine System: Lingual Thyroid
1. 99mTc pertechnetate is taken up (trapped) by thyroid follicular
cells like iodine but not organified. I23I is taken up
and organified.
2. Lower radiation exposure to the pediatric patient.
3. Focal uptake at the base of the tongue. Normal in submandibular
glands and mouth. No thyroid in neck.
4. Lingual thyroid.
99mTc pertechnetate thyroid scan in a patient with clinical hyperthyroidism.
1. Describe the scintigraphic findings.
2. Describe the scan evidence that supports the reported hyperthyroidism.
3. What is the differential diagnosis regarding the left lobe?
4. The right lobe is two times normal size by examination. The left lobe is not palpable, no nodules are felt, and no scars are present. What is the most likely diagnosis?
Endocrine System: Thyroid Left Lobe
Agenesis—Craves' Disease
1. Uniform uptake in a bulbous-appearing right lobe, with
out focal areas of increased or decreased uptake. No activity
in the expected location of the left lobe or elsewhere in the
neck or upper chest.
2. The uniform activity in the right lobe is more intense than
in the salivary glands, indirect evidence of an elevated
uptake in the absence of intrinsic salivary gland disease.
3. Surgical excision, replacement by hypofunctioning adenoma
or carcinoma, suppression by autonomously functioning
adenoma on the right, agenesis of the left lobe with Graves' disease of the solitary right lobe.
4. Graves' disease with agenesis of the left lobe.
A 45-year-old man had surgery for hyperparathyroidism that has persisted postoperatively.
1. What is the radiopharmaceutical and study?
2. Describe the scintigraphic findings.
3. What is the differential diagnosis for these findings?
4. What is the likely diagnosis in this clinical setting?
Endocrine System: Mediastinal Parathyroid Adenoma
1. Parathyroid scan with 99mTc sestamibi or 99mTc tetrofosmin.
(Image quality would be inferior with 201Tl.)
2. Focal persistent uptake in the mediastinum, normal salivary,
liver, cardiac uptake. Apparent axillary uptake resolves
with arms elevated, thus is caused by skin folds.
3. Various benign or malignant neoplasms.
4. Mediastinal parathyroid adenoma.
A 47-year-old woman with recent onset of severe hypertension and elevated catecholamine levels.
1. What is the radiopharmaceutical?
2. What is the radiopharmaceutical's mechanism of uptake?
3. What is the accuracy of this study for locating the site of disease? What is the disease?
4. What other diseases take up this radiopharmaceutical?
Endocrine System: MIBG—Pheochromocytoma
1. 131I meta-iodo-benzyl-guanidine (MIBG).
2. Localization occurs through the norepinephrine reuptake mechanism. It localizes in catecholamine storage vesicles in presynaptic adrenergic nerve endings and the cells of the
adrenal medulla.
3. Sensitivity, 90%; specificity, 95% for detection of pheochromocytomas.
4. Various neuroendocrine tumors take up the radiopharmaceutical:
neuroblastoma (90%), carcinoid (50%), and medullary carcinoma of the thyroid (25%).
Bone scans A, B, and C.
1. Describe the bone scan findings.
2. Interpret the studies.
3. Name the physical principle that is involved in C.
4. Name the most likely type of material involved in C.
Skeletal System: Arterial Injection, Boot Artifact, Photopenic Attenuation Artifact
1. A, Increased uptake in the right upper extremity from
elbow through hands. B, Uptake outside bone in both feet
and ankles, right greater than left. Urinary contamination
of scrotum. C, Photopenia of a portion of the right midhumerus
on the posterior view only. Lumbar scoliosis. Left
hip prosthesis.
2. A, Intraarterial injection. B, Urinary contamination of
socks (boot artifact). C, Attenuation artifact of right
3. Attenuation of photons.
4. Metal.
Three-view format of selected coronal, sagittal slices, and transaxial images from SPECT bone scans of two patients
with cancer and low back pain. The bottom right images are the posterior projection preprocessed raw images.
1. Describe the scintigraphic SPECT findings in studies A and B.
2. Give the likely diagnosis in both patients.
3. Why is accuracy of lumbar spine SPECT higher than for planar imaging?
4. How can bone SPECT be clinically helpful in diagnosing disease in a patient with recurrent pain 1 year after spinal surgery?
Skeletal System: Improved Specificity with Bone Scan Lumbar SPECT
1. A, Uptake in the region of the L4 right pedicle, extending
to the vertebral body. B, Uptake in the region of the L2
facet joints bilaterally, right greater than left.
2. A, Metastatic tumor. B, Articular facet osteoarthritis.
3. SPECT improves the target-to-background ratio by
removing overlying activity from adjacent slices and allows
for three-dimensional display.
4. One year after surgery a healed fusion has no more than
minimally increased activity, whereas a pseudoarthrosis
shows active bony repair with increased activity.
A patient was referred for bone scan because of joint pain.
1. Describe the scintigraphic bone findings.
2. Describe any soft tissue findings. What is the likely cause?
3. What other imaging study should be ordered?
4. What is the diagnosis and most likely common cause for this scan pattern?
Skeletal System: Pulmonary Hypertrophic Osteoarthropathy
1. Diffuse increased uptake in the upper and lower extremi
ties and periarticular regions of the elbow, wrist, and ankle
joint. Uptake in the seventh right rib anteriorly.
2. Diffuse uptake in the right thorax. The most common
cause is malignant pleural effusion.
3. Chest x-ray.
4. Hypertrophic pulmonary osteoarthropathy. Bronchogenic
cancer of the lung.
A patient with diabetes was referred with cellulitis of the right lower leg to rule out osteomyelitis.
1. Discuss the advantage of a three-phase bone scan compared with the delayed phase only.
2. Describe the scintigraphic bone scan findings. Flow (A), blood pool (B), delayed (C),
D, Radiograph.
3. Provide the differential diagnosis.
4. What is the most likely diagnosis?
Skeletal System: Gangrene of Toes
1. The flow and blood pool phases increase the specificity of
the diagnosis and narrow the differential diagnosis.
2. Diffuse increased blood flow and blood pool to the foot
and ankle of the right lower extremity. No blood flow,
pool, or uptake of the right third and fourth toes, mild
increase in all bones on the delayed image, slightly worse
at the first metatarsophalangeal (MTP) joint.
3. Vascular insufficiency, prior surgery, acute osteomyelitis,
frostbite, replacement by tumor, artifact.
4. Arterial insufficiency and gangrene of the third and fourth
toes; cellulitis; mild arthritis of first MTP joint.
1. Describe the bone scan abnormality. A, Flow. B, Immediate and delayed plantar images.
2. Provide the differential diagnosis.
3. Given the radiograph (C), name the entity. List at least three other sites that are subject to the same process.
4. List at least three conditions associated with this entity
Skeletal System: Avascular Necrosis of
Metatarsal Head (Freiberg's Disease)
1. The three-phase bone scan demonstrates abnormal
increased blood flow and blood pool activity in the region
of the second and third metatarsal heads. The delayed
bone phase demonstrates increased activity in the bones in
the same distribution.
2. Fracture, osteotomy, osteomyelitis, primary or secondary
neoplasm, avascular necrosis.
3. Avascular necrosis. Tarsal navicular, carpal lunate, femoral
head, humeral head, ring apophyses of the spine, tibial
4. Trauma, hypercortisolism, collagen vascular disease, chronic
renal disease, aspirin, sickle cell disease, alcoholism, dysbaric
A bone scan was requested for evaluation of hip pain and low-grade fever in an 11-year-old. The hip radiograph was
1. What imaging instructions should be given to the technologist?
2. Describe the scintigraphic findings {above, blood flow; below left, blood pool; below middle and right, delayed
3. Provide the differential diagnosis.
4. Bone biopsy: neuroblastoma. Name another radiopharmaceutical used in this disease.
Skeletal System: Neuroblastoma Mimicking
1. Three-phase bone scan with attention to the hips because
of the acute nature of the symptoms and infection is a
clinical consideration.
2. Moderately increased flow, blood pool, and delayed uptake
in the proximal right femur metaphysis.
3. Osteomyelitis, fracture, primary or secondary malignant
tumor (monostotic), fibrous dysplasia.
4. I31I metabenzylguanidine (MIBG) and '"In pentetreotide,
a somatostatin receptor radiotracer.
A 5-year-old with precocious puberty.
1. Name two findings that might be seen when examining this patient.
2. Describe the scan findings.
3. What bone lesion is most likely?
4. Name the syndrome that this patient has.
Skeletal System: Fibrous Dysplasia,
McCune-Albright Syndrome
1. Pigmented "cafe-au-lait" skin lesions, gynecomastia.
2. Abnormal uptake is seen in the frontal bone, left femur,
left tibia, with a nonuniform pattern of uptake in the long bones.
3. Polyostotic fibrous dysplasia.
4. McCune-Albright syndrome.
1. Describe the bone scan skeletal abnormalities.
2. Provide the differential diagnoses for the bone abnormalities.
3. Describe the ancillary nonbone abnormalities.
4. Given the presence of nonbone and bone abnormalities, provide the most likely diagnosis.
Bone: Renal Osteodystrophy
1. Increased cortical radiotracer activity in the long bones of
the upper and lower extremities. "Railroad tracking" and
bowing of the femurs. Bilateral hip prostheses.
2. Hypertrophic osteoarthropathy, vitamin A intoxication,
fluorosis, renal osteodystrophy, thyroid acropachy,
3. High bone-to-soft tissue uptake ratio. Renal nonvisualization.
Minimal bladder activity. Additional history: patient
is undergoing dialysis following a failed kidney transplant.
4. The scan is characteristic of renal osteodystrophy. Prior hip
replacements for avascular necrosis caused by steroid therapy
related to the kidney transplant.
Newly diagnosed prostate cancer.
1. List the abnormalities demonstrated in the bones.
2. Provide the most likely diagnosis.
3. List any other abnormalities.
4. What is most likely diagnosis?
Skeletal System: Lumbar Spinal Fusion, Renal
1. Abnormal contour at the L4 and L5 level, with relative
increase in the diameter of the apparent vertebrae, central
photopenia in a well-defined geometrical pattern sur
rounded by increased activity. Abnormal increased uptake
in a crescent pattern in the right sacral ala.
2. Posterior fusion with bone graft material seen lateral to the
expected contour of the vertebra. The photopenia is
caused by orthopedic hardware (pedicle screws and plates).
The right iliac crest is the bone graft donor sice.
3. Nonvisualization of kidneys in the expected location;
tracer excretion is present in the bladder. Faint soft tissue
uptake overlying and extending superior to the right ilium.
4. Lumbar spinal fusion. Renal transplant in the right iliac fossa.
1. The patient was referred for back pain. Describe the bone findings.
2. Describe any other nonosseous findings.
3. Provide the differential diagnosis for the bone abnormality.
4. List three possible primary neoplasms.
Skeletal System: Metastases to Bone (Cold)
and Adrenal Gland
1. Photopenia of a low thoracic vertebra, probably Til.
2. Ptotic kidneys, abnormal soft tissue uptake seen between
the posterior right eleventh and twelfth ribs.
3. Primary or metastatic neoplasm, attenuation from external
or internal source, e.g., buckle on back of clothing, metal
lic orthopedic hardware, or prior vertebroplasty.
4. Breast, colon, lung; neuroblastoma in a child, but clearly
this patient is an adult.
Limited bone scan (left) in patient with left distal femur osteosarcoma. A different type of nuclear study was done
before (middle) and after chemotherapy (right).
1. Describe the bone scan findings.
2. Is a whole-body bone scan warranted?
3. What is the second radiopharmaceutical used?
4. Describe the findings of the second study. What is the clinical significance of the scan findings before and after
Bone: Osteosarcoma and 201TI
1. Increased uptake in the lateral margin of the distal metaphysis
compatible with the known osteosarcoma. Relative
photopenia medial to this uptake.
2. Yes, for staging to detect other sites of tumor.
3. 201Tl. 99mTc sestamibi can be used for the same purpose.
4. Prechemotherapy: very increased uptake in the osteosar
coma. Postchemotherapy: resolution of the uptake. The
degree of decrease in 2O1T1 uptake after therapy correlates
with tumor response to chemotherapy and tumor necrosis.
Previously resected chondrosarcoma. Evaluate for metastases.
1. Describe the bone scan findings.
2. Provide the differential diagnoses.
3. List at least three conditions that predispose patients to this condition.
4. List two other sites that are subject to the same process.
Skeletal System: Avascular Necrosis
of Femoral Heads
1. Nonvisualization of the left ilium; leg length discrepancy as a result of high-riding left hip; and increased uptake both femoral heads, left worse than right.
2. The ilium has been surgically resected. Femoral heads: avascular necrosis, fractures, osteotomies; slipped capital femoral epiphyses in the appropriate age group.
3. Trauma, steroid administration, sickle cell disease, collagen vascular disease, chronic renal disease, aspirin, alcoholism, dysbaric conditions.
4. Humeral head, tarsal navicular.
Patient ,4 is a 50-year-old woman with recurrent cellulitis and chronic edema of the left lower extremity. Patient B is a
60-year-old man with swelling in the left upper thigh for several months after femoral artery surgery. Radionuclide
lymphoscintigraphy was performed for both patients.
1. What radiopharmaceutical is most commonly used in the United States for lymphoscintigraphy?
2. What is the differential diagnosis of chronic lower extremity edema if systemic disease, e.g., cardiac, hepatic, renal,
have been excluded?
3. Describe the lymphoscintigraphic pattern in these two patients.
4. What are the diagnoses?
Musculoskeletal System: Lymphoscintigraphy
of the Lower Extremities
1. Filtered 99nTc sulfur colloid.
2. Chronic venous insufficiency and lymphedema, primary
or secondary.
3. A, Normal deep lymphatic flow to femoral and inguinal
nodes on the right. Dermal backflow pattern on the distal
left lower extremity. B, Abnormal focal accumulation in
the medial left thigh. One superficial collateral lymphatic
vessel on the right.
4. A, Lymphatic obstruction (left). B, Extravasation into a
lymphocele (left). Right, Asymptomatic; normal.
A 48-year-old patient with COPD and ciaudication. She has asthma. SPECT perfusion images (A, short-axis; B, verti
cal long-axis; and C, select gated poststress SPECT images). The left ventricular ejection fraction (LVEF) is 20%.
1. What is the appropriate stress technique for this patient? In what other patients is this the stress method of choice?
2. Why is this considered a second-line pharmacological stress agent?
3. Describe the SPECT image findings in this case.
4. What is the mechanism of cardiac uptake for 99mTc sestamibi and 99mTc tetrofosmin?
Cardiovascular System: Dobutamine Stress
1. Dobutamine stress. Patients who are not candidates for
either exercise, e.g., claudication, or vasodilator stress, e.g.,
patients with asthma.
2. The common occurrence of side effects including angina
and the inability of a significant number of patients to tol
erate the required dose.
3. Mild fixed anteroseptal perfusion defect with decreased wall
thickening. Severe fixed inferior defect with absent wall
thickening. Dilated left ventricular cavity. No reversibility.
Myocardial thickening and wall motion signify functioning
viable myocardium.
4. 99mTc sestamibi, an isonitrile monovalent cation, diffuses
passively from the blood into myocardial cells because of its
lipophilicity, then localizes in the mitochondria. 99mTc tetrofosmin,
a diphosphene, has a similar uptake mechanism.
A, Exercise myocardial SPECT perfusion studies. The patient's initial stress study acquisition (above) and repeat acquisition
(below), B, Sinograms for the first (left) and second (right) scans.
1. Describe the findings based on the SPECT images and sinograms.
2. Describe the purpose of the sinogram.
3. List other techniques in addition to the sinogram that can be used similarly.
4. Provide the diagnosis.
Cardiovascular System: Patient Movement
1. A, The first study (above) shows an abnormal configura
tion of the anterior wall; the repeat study (below) is nor
mal. B, The initial sinogram shows a discontinuity or
break; the second is normal.
2. To visually present the raw unprocessed projection images
to evaluate for patient motion.
3. Review SPECT projection data, image by image, or in
cinematic display.
4. Artifact caused by patient motion.
Stress and rest SPECT myocardial perfusion images and a single projection of unprocessed acquisition data from a cine
loop (right) are provided.
1. What radiopharmaceuticals can be used for this stress study?
2. Describe the SPECT findings and any additional information available from the cine loop stress and rest projection
3. List the differential diagnosis.
4. List the advantages of adding ECG-synchronization (gating) to SPECT myocardial perfusion imaging.
Cardiovascular System: Breast Attenuation
1. 99mTc sestamibi (Cardiolite), tetrofosmin (Myoview), and
not 201Tl because the gall bladder is seen.
2. Mild fixed defect in the anterior wall. Projection images:
decreased uptake in the upper half of the heart at stress
and rest in a curvilinear configuration.
3. Breast attenuation, anterior wall myocardial scar (infarction).
4. Assessment of regional wall motion, wall thickening, and
ejection fraction.
Dipyridamole (Persantine) sestamibi SPECT myocardial perfusion study. Short-axis (A) and vertical long-axis images (B)
are shown.
1. List the mechanism of action of dipyridamole. List foods and medications that counteract its pharmacological effect.
2. Describe the timing of radiotracer injection with respect to dipyridamole administration and the management of
dipyridamole side effects.
3. Describe the SPECT image findings.
4. List maneuvers to deal with the problem of abdominal (liver and intestinal) activity.
Cardiovascular System: Dipyridamole, Inferior
Ischemia, Overlying Bowel Activity
1. Dipyridamole inhibits the action of adenosine deaminase,
thus increasing endogenous adenosine, a potent coronary
artery vasodilator. Coffee, tea, caffeine-containing soft
drinks or foods such as chocolate, theophylline, and
2. Dipyridamole is infused for 4 minutes. Radiotracer is
given 3 minutes after completion of the dipyridamole
infusion. Side effects can be reversed with intravenous
3. Mild to moderate fixed defect of the anterior wall. Severe,
mostly fixed defect involving the entire inferior wall, but a
small area of reversibility in the inferoapical-apical region.
Dilated left ventricle.
4. Obtain delayed SPECT to allow additional hepatic clear
ance or movement of bowel activity, have the patient drink
water, or both.
A 45-year-old woman with hypercholesterolemia. A, Short-axis and B, vertical long-axis SPECT stress myocardial perfusion
images, and raw data sequential projection images from the stress (C) and rest (D) scans.
1. Describe the SPECT perfusion image findings.
2. List three reasons to review the raw data projection images.
3. Provide any information available from the acquisition projection images.
4. What is the most likely diagnosis?
Cardiovascular System: Attenuation Caused
by Change of Breast Position
1. Partially reversible perfusion defect in the apicalantero-
septal wall. Mild fixed defect in the inferolateral
wall. Dilated left ventricle.
2. To detect patient motion, camera malfunction, or
3. Decreased radiotracer in the upper portions of the
myocardium that appears somewhat different in location
on the stress and rest projection images.
4. Position-dependent breast artifact. Concomitant ischemia
may or may not be present.
A 62-year-old man with known CAD had fixed defects with no reversibility on a 99mTc perfusion SPECT study at
another hospital. This is a rest-rest 20lTl SPECT study. A, Short-axis, B, vertical long-axis; C, horizontal long-axis.
1. Describe the SPECT findings on the initial rest and the 4-hour delayed rest study.
2. What is the clinical significance of these findings?
3. Based on the available evidence, should revascularization be considered?
4. What is hibernating myocardium?
Cardiovascular System: 201TI Viability Study
1. Initial rest images show extensive defects: (1) the anterior
wall extending to the apex, septum, and anterolateral wall;
and (2) the inferolateral wall extending to the inferior and
lateral regions. Delayed rest images show some improve
ment in perfusion in the anterior wall extending to the
apex and septum and anterolateral region.
2. There is viable myocardium in the left anterior descending
(LAD) artery distribution.
3. Yes.
4. Chronic myocardial ischemia where both blood flow and
function (contractility) are reduced. Although the myocar
dium is viable, the lack of wall motion mimics infarction.
Stress (top row), 4-hour delay (middle row), and 24-hour (bottom row) planar 201Tl planar images obtained in a patient
too heavy for the SPECT table.
1. What is the mechanism for 201Tl uptake at stress and rest?
2. What is redistribution?
3. Name the three views and describe the scintigraphic findings.
4. List other circumstances in which planar imaging may be preferable to SPECT.
Cardiovascular System: Planar 201TI
with Ischemia
1. 2O1T1 behaves like a potassium analogue using the ATPase
sodium-potassium pump. Almost 90% of thallium is
extracted on first pass through the coronary circulation at
normal flow. Uptake is proportional to blood flow. At high
flow rates, extraction is less. Five percent of the adminis
tered dose localizes in the myocardium.
2. After initial cellular uptake, 201Tl undergoes redistribution
throughout the body. As 201Tl clears from the myocardi
um, it is replaced by circulating 201Tl. This is the basis for
the stress redistribution imaging strategy. Cold defects seen
on early images are the result of decreased flow and there
fore decreased 201Tl delivery. Ischemic myocardium will
"fill in" on 2- to 4-hour delayed imaging. No fill-in is seen
with infarct. With severe ischemia, e.g., hibernating
myocardium, fill-in may require a longer time, up to 24
3. Lefi: left lateral; middle: anterior; right: left anterior oblique.
Reduced radiotracer in the inferolateral-inferior region,
which partially normalizes on the delayed 4-hour redistribu
tion images and completely redistributes by 24 hours.
4. Claustrophobia. Some patients do not tolerate the SPECT
camera, particularly a multiheaded camera.
PET cardiac study using two different radiopharmaceuticals. Short, vertical, and horizontal long-axis images are
shown. Top row of each set is 13N ammonia. The bottom images are 18F FDG.
1. What physiological parameter does the 13N ammonia distribution reflect?
2. Similar information could be obtained using what other clinically used positron radiopharmaceutical?
3. What is the rationale for the use of 18F FDG?
4. Describe the image findings and interpret the results.
Cardiovascular System: 13N Ammonia/FDG
Cardiac Viability Study
1. Myocardial perfusion.
2. 82Rb.
3. FDG is taken up by ischemic myocardium.
4. The I3N ammonia study shows decreased perfusion in the
proximal two thirds of the lateral wall extending to the
anterolateral and inferolateral regions. The FDG uptake
is mismatched. Increased FDG uptake indicating ischemia
is seen where the 13N ammonia images show hypoperfusion.
Diagnostic of myocardial viability (hibernating myocardium).
A 40-year-old patient with malignant lymphoma was treated with doxorubicin (Adriamycin). A radionuclide ventriculogram
(RVG) performed at the time of initial diagnosis reported a 60% LVEE A, Follow-up RVG with all 16 image
frames and left ventricular time-activity curves (TACs) before (B) and after (C) chemotherapy.
1. Discuss sequential images and the TACs.
2. What is the likely diagnosis?
3. List features that should be included in reporting RVG or MUGA studies.
4. List three reasons why radionuclide ventriculography is preferred to echocardiography for monitoring left ventricu lar function.
Cardiovascular System: Doxorubicin Toxicity
1. Sequential images (A) show a LVEF within normal range.
The ventricle appears mildly dilated. End-systole is image
number 7. TACs show counts for each of 16 frames of the
gated acquisition. B is normal. C shows deterioration from
baseline with a slower, broad diastolic upslope and
decreased stroke volume (ESV-EDV). The pattern is com
patible with ventricular dysfunction, predominantly
diastolic, and deterioration compared with the baseline
study. LVEF was calculated to be 50%.
2. Doxorubicin toxicity.
3. Qualitative assessment of cardiac chambers and great ves
sels in terms of size and relationships, regional wall motion
based on review of cinematic display, and quantitative
analysis (LVEF).
4. Echocardiography is operator dependent, relies on visual
estimates of LVEF, and may not be technically feasible in
up to 30% of patients because of poor acoustic window.
RVG is relatively free of operator-dependent factors, is
generally reproducible within an institution and across
institutions, and is not limited by acoustic windows.
A 99mTc pyrophosphate study is obtained to evaluate for myocardial infarct in a patient with equivocal ECG and bor
derline enzyme levels.
1. What information should be obtained before the injection?
2. Describe the scintigraphic SPECT (A, transverse; B, coronal) findings in this patient.
3. Give a differential diagnosis of the scan finding.
4. Name another infarct-avid radiopharmaceutical.
Cardiac: Pyrophosphate SPECT Infarct
1. The time of the suspected event. Depending on the time
of the event and whether chest pain is ongoing, a perfusion
SPECT study may be more appropriate.
2. Focal abnormal uptake is seen at the left apex.
3. Focal apical myocardial infarct, severe ischemia, aneurysm,
focal myocarditis, focal pericardial calcification.
4. '"In antimyosin.
Two patients have radionuclide blood flow imaging after right upper extremity injection.
1. Describe the route of the radiotracer in patient A. Give an interpretation.
2. What are the image findings and interpretation of patient B?
3. What radiopharmaceuticals could be used for this study?
4. What is the framing rate (seconds/frame) and minimum injected dose required to obtain a good flow study?
Cardiovascular System: Superior Vena Cava
1. Subclavian vein, superior vena cava, right ventricle, lungs,
left ventricle, carotids, aorta. Normal flow pattern.
2. Venous occlusion at the superior vena cava with collateral
flow over the anterior chest. (This patient had lung cancer.)
3. Any 99mTc radiopharmaceutical. All that is needed is
enough activity for a good flow study. 99mTc DTPA often
is used because it is cleared rapidly by the kidneys and can
be repeated if necessary.
4. 1 to 3 seconds/frame; 5 mCi or greater.
A 62-year-old patient with right-sided chest discomfort and shortness of breath. A, Posteroanterior chest radiograph;
B, perfusion; C, ventilation.
1. Describe the ventilation perfusion image findings.
2. Interpret the study. Give your reasoning.
3. What is the likelihood of pulmonary embolus in this patient?
4. What are the most common chest x-ray findings in patients with pulmonary emboli?
Pulmonary System: High Probability of
Pulmonary Embolus
1. Perfusion: decreased right lower lobe except for the superior
segment. Ventilation: normal except for mildly truncated
right lower lobe consistent with subpulmonic effusion.
2. High probability of pulmonary embolus. Mismatch
between perfusion and ventilation in the basal segments.
The perfusion defect is considerably larger than the pleural
effusion on the radiograph.
3. Greater than 80%.
4. Most common: normal. Next most common: atelectasis.
These are also the most common x-ray findings in patients determined by angiography not to have emboli.
A 59-year-old patient with COPD complains of right-sided chest discomfort and shortness of breath.
A, Posteroanterior chest radiograph; B, lateral chest; C, perfusion; D, ventilation.
1. Describe the ventilation-perfusion image findings.
2. Interpret the study.
3. What is a stripe sign and what is its significance?
4. What is the physiological basis of a stripe sign?
Pulmonary System: Stripe Sign
1. Decreased perfusion in the right upper lobe (apical and
anterior segments). Stripe sign of the posterior segment of
the right upper lobe. Normal ventilation.
2. Two segmental mismatches. High probability of pul
monary embolus.
3. Its presence signifies perfused lung tissue between a perfu
sion defect and the adjacent pleural surface. Its presence
can be used to classify a segment as not related to pul
monary embolus, and in some cases, lower the probability
of a scan from intermediate to low.
4. Usually a manifestation of airway obstruction. The sign
has been correlated with CT and PET showing spared per
fusion of the cortex of the lung in asthma and emphysema.
A ventilation-perfusion lung scan is ordered for increasing shortness of breath. Chest radiograph (not shown) findings
were negative.
1. Describe the scintigraphic findings (A, perfusion, anterior and posterior only; B, 133Xe washin-washout ventilation
image sequence; C, CT).
2. What pulmonary embolus probability category would you assign?
3. Provide the differential diagnosis.
4. A chest CT was performed to further evaluate for the symptoms. What is the most likely diagnosis?
Pulmonary System: Unilateral Matched
Ventilation-Perfusion Abnormality
1. Perfusion images: global decreased perfusion to the entire left lung, more striking than the ventilation. 133Xe ventilation images: decreased and delayed ventilation of the entire left lung. Washout images show no significant air trapping.
2. Low probability.
3. Hilar mass (lung cancer or adenopathy), severe unilateral parenchymal lung disease, Swyer-James syndrome, hypoplastic pulmonary artery, prior shunt for congenital heart disease.
4. Lung cancer.
A 3-year-old child was referred for a 99mTc macroaggregated albumin (MAA) study.
1. Describe the scintigraphic findings.
2. What is the diagnosis?
3. Describe the radiopharmaceutical's mechanism of uptake.
4. What are contraindications to this study?
Pulmonary System: Right-to-Left Shunt
Demonstrated by 99mTc MAA
1. Uptake of the radiotracer in the brain, lungs, kidneys, and
2. Right-to-left shunt.
3. 99mTc MAA particles are larger than capillary size. When
given intravenously, the particles occlude the first arteriolarcapillary
bed they reach normally, the lungs. With a rightto-
left shunt, some will bypass the lungs and be delivered
systemically in proportion to the size of the shunt.
4. Relative contraindications include pregnancy, severe pul
monary hypertension, and right-to-left shunt. There are
no absolute contraindications.
A 55-year-old patient with a remote history of thrombophlebitis in the left thigh has recurrent similar pain. A Foley
catheter is in place.
1. What is the radiopharmaceutical and scintigraphic study?
2. What is its mechanism of uptake?
3. What are the scintigraphic findings?
4. What are its clinical indications?
Thrombophlebitis: AcuTect (99mTc apcitide)
1. Radionuclide venogram with AcuTect (<J9mTc apcitide).
2. AcuTect is a synthetic peptide that binds to the glycoprotein
GPIIB/IIIa receptors on the surface of activated
3. Increased uptake in the left deep venous system extending
from the proximal to distal thigh consistent with acute
deep venous thrombophlebitis. Diffuse increased uptake is
seen throughout the soft tissue of the left lower extremity.
4. To differentiate acute thrombophlebitis from old inac
tive thrombophlebitis. It also can be used to diagnose acute thrombophlebitis when Doppler ultrasonography is nondiagnostic.
A 56-year-old paraplegic patient has fever of uncertain origin. No localizing signs or symptoms are present.
1. Which radiopharmaceutical was used? What others could be used for this purpose?
2. Which organ receives the highest radiation absorbed dose? Estimate the dose.
3. What is your interpretation of this whole-body scan (A) and pelvic spot (B)?
4. What is the photopeak(s) of the radionuclide used? What is its half-life?
Infection and Inflammation: inln Oxine
WBCs—Right lleum Osteomyelitis
1. "'In oxine or 99mTc HM-PAO leukocytes. 67Ga could also be used. The intense spleen uptake is consistent with a radiolabeled
leukocyte study; "'In oxine leukocytes were used. The image resolution is poor compared with 99mTc leukocytes.
2. Spleen, approximately 15 to 20 rads.
3. Abnormal focal uptake in right groin (there has been a femoral line) and in the right ileum, indicating osteomyelitis.
4. 173, 247 keV. Physical half-life is 77 hours.