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236 Cards in this Set

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A burst fracture of the C1 ring?
jefferson fracture
any break in the bony ring of a vertebra that occurs on a slice that shows the __________ _______ is a spondylolysis until proved otherwise?
basivertebral plexus
Helps distinguish myositis ossificans from parosteal osteosarcoma?
Parosteal sarcoma demonstrates central clumps of calcification and myositis ossificans has peripheral ossification/calcification.
Define disk bulge, sequestered or free fragment?
Disk bulges can be diffuse, broad based, or focal but are attached to the disk. Sequestered or free fragments occur when disk material migrate from parent disk.
Distinguishing a free fragment from a Tarlov cyst or conjoined nerve root?
A free fragment is hyperdense to thecal sac and Tarlov cyts and conjoined nerve roots are isodense to thecal sac.
Lateral disk protrusion affects what nerve root?
A nerve rooth that has already exited the neuroforamen at a more cephalad level.
Congenital causes of spinal stenosis?
Achondroplasia, Morquio's disease, idiopathic spinal stenosis
Acquired spinal stenosis causes?
Degenerative disk disease, post-traumatic stenosis, postsurgical stenosis, Paget's disease, calcification of posterior longitudinal ligament.
Anatomic classification of spinal stenosis?
Central canal stenosis, neuroforaminal stenosis, lateral recess stenosis.
Most useful CT criteria for diagnosing central canal stenosis?
Obliteration of epidural fat, flattening of thecal sac.
Pars interarticularis defect?
Spondylolysis
Anterior displacement of a cephalad vertebral body with respect to a caudad vertebral body?
Spondylolisthesis. Grade I (<25%), II (25-50%), III (50-75%), IV (75-100%).
Most common site for coalition?
Calcaneonavicular joint.
Finding causing the greatest concern for metastatic bone disease or multiple myeloma involvement?
A permeative process.
Spinal hemangioma CT features?
vertical trabecular thickening, may contain fat, may see phleboliths.
Schmorl's node?
Herniation of disk material through end plate of vertebral body.
Tarlov cysts?
Nerve sheath dilatations of fluid density at CT, when large enough can cause bone erosion, particulary within the sacrum.
Paget's disease on CT?
Purely lytic or sclerotic or mixed. Bone overgrowth, Cortical thickening, disorganized trabecular thickening, in pelvis-thickenign of iliopectineal or ilioischial lines.
Fibrous dysplasia?
Congenital disorder of bone, fibrous tissue, chondral tissue, and even cysts within bone. Non-aggressive appearance.
Common right-sided anomalous pulmonary venous return insertions?
SVC azygos vein, IVC, Right atrium.
Common left-sided anomalous pulmonary venous return insertions?
Left brachiocephalic vein, persistent left SVC, Coronary sinus.
CT features that suggest lung cancer?
Irregular or spiculated margine, Lobulated contour, Air bronchograms or cysts within nodule, Nodular cavitation, > 2 cm.
Lung hamartoma CT features?
Smooth, rounded, or lobulated contour. Fat 60% Fat and calcification 30% Diffuse calcification 10%--"popcorn".
4 findings of rounded atelectasis?
1. Ipsilateral pleural thickening or effusion. 2. Contact between lung lesion and pleural surface. 3. "comet tail" sign. 4. Volume loss of lobe involved.
Air-crescent sign?
Lung mass capped by a crescent of air. Most typical of mycetoma (fungus ball). Fungus ball (Aspergillus) forms in preexisting cyst or cavity.
Lung abscess CT features?
Necrosis or cavitation within area of pneumonia or dense consolidation.
Satellite nodules and galaxy sign?
Granulomatous lesions with smaller nearby nodules--satellite. In sarcoidosis, galaxy sign is a larger nodule with nearby grouped smaller nodules
Benign pulmonary nodule calcification patterns?
Diffuse (granuloma), Central "bullseye" (histoplasmosis), Popcorn (hamartoma), Concentric "target" (histoplasmosis).
Benign pulmonary nodule doubling times?
< 1 month, or > 16 months.
What increase in diameter equals a doubling of volume?
26% increase (10 mm to 12.6 mm)
Differential, multiple large pulmonary nodules?
Metastases Lymphoma Bronchogenic carcinoma Bacterial, fungal, and sometimes viral infections Granulomatous disease Sarcoidosis Wegener's granulomatosis Rheumatoid lung Amyloidosis Septic emboli
Pulmonary metastasis characteristics?
Typically round and well-defined. Cavitation and calcification can be seen.
Signet ring sign?
Bronchiectasis. Cross section of pulmonary artery branch adjacent to dilated, ring-shaped bronchus.Bronchus diameter exceeds adjacent artery's
Bronchiectasis patterns in cystic fibrosis and allergic bronchopulmonary aspergillosis?
CF-bilateral, upper lobes, most severe at parahilar lungs. ABPA-central bronchiectasis.
Causes of interlobular septal thickening as predominant finding at HRCT?
1. Lymphatic spread of carcinoma. 2. Interstitial pulmonary edema. 3. Alveolar proteinosis. 4. Sarcoidosis.
Common causes of fibrosis and honeycombing as predominant HRCT findings?
IPF 65%, Collage vascular diseases (RA, scleroderma), Drug-related fibrosis, Asbestosis, End-stage hypersensitivity pneumonitis, End-stage sarcoidosis.
3 distributions of pulmonary nodules at HRCT?
Perilymphatic nodules (pleural surface, large vessels and bronchi, interlobular septa, centrilobular regions), Random nodules (miliary TB, hematogenous metastases), Centrilobular nodules (tree-in-bud--endobronchial TB, MAC/MAI, CF, bronchiectasis, bronchopneumonia).
CT features of pulmonary lymphangitic spread of carcinoma?
Interlobular septal thickening, Peribronchial interstitial thickening, Thickening of fissures, Lymph node enlargement, Patchy distribution.
CT features of pulmonary hematogenous spread of tumor?
Random distribution, Fissures and pleural surface involvement, Bilateral, Large nodules.
CT features of IPF (idiopathic pulmonary fibrosis--UIP is histology pattern)?
Intralobular interstitial thickening, Honeycombing, Traction bronchiectasis and bronchiolectasis, Subpleural, posterior, and basal lungs, Ground-glass opacity.
Nonspecific interstitial pneumonia (NIP, collagen vascular disease) CT features?
Ground-glass opacity, Posterior basal lungs-sparing immediate subpleural lung, Reticulation, traction bronchiectasis and bronchiolectasis, Honeycombing-rare.
Active sarcoidosis CT features?
Perilymphatic nodules, Patchy, upper lobe predominance, Hilar, mediastinal node enlargement, Ground-glass opacity (small granulomas).
HRCT findings in end-stage sarcoidosis?
Irregular septal thickening, Architectural distortion, Parahilar conglomerate masses, Honeycombing, Hilar and mediastinal node enlargement.
Pulmonary lymphangitic spread of carcinoma?
Interlobular septal thickening, Peribronchial interstitial thickening Patchy or unilteral distribution Lymph node enlargement.
Pulmonary hematogenous spread of tumor?
Random distribution, Involvement of fissures and pleural surfaces, Bilateral distribution, Large nodules.
Idiopathic pulmonary fibrosis CT features?
Intralobular thickening, Honeycombing, Traction bronchiectasis and bronchiolectasis, Predominant subpleural, posterior, basal lung regions, Ground-glass opacity.
Nonspecific interstitial pneumonia CT features?
Ground-glass opacity, Predominant posterior and basal lung, sparing the immediate subpleural lung, Reticulation, traction bronchiectasis and bonchiolectasis, Honeycombing.
Collagen vascular disease as lung disease?
Rheumatoid lung, scleroderma, and other collagen disease (UIP, NSIP, BOOP)
Active pulmonary sarcoidosis CT features?
Perilymphatic nodules, Patchy, Upperlobe predominance, Hilar, mediastinal nodes, Ground-glass opacity, small granulomas.
End-stage sarcoidosis?
Irregular septal thickening, Architetural distortion, Parahilar conglomerate, honeycombing, Hilar, mediastinal nodes.
Silicosis and Coal Worker's pneumoconiosis?
Perilymphatic nodules, Symmetric distribution, Posterior lung predominance, Upper lobe predominance, Conglomerate masses, Hilar, mediastinal nodes (egg-shell calcification).
Pulmonary Tuberculosis CT features?
Endobronchial spread (centrilobular nodules, tree-in-bud, focal areas of consolidation, bronchial wall thickening or bronchiectasis, pathcy or focal), Miliary spread (random nodules, 1-5 mm, Usually diffuse).
Pulmonary alveolar proteinosis?
Filling of alveolar spaces with lipid-rich proteinaceous material, Patchy or geographic ground-glass opacity, smooth, interlobular septal thickening in ground-glass--"crazy paving"".
Hypersensitivity pneumonitis, subacute stage CT features?
Patchy or geographic ground-glass opacity, Poorly defined centrilobular nodules or ground-glass opacity, Mosaic perfusion, Air trapping.
Bronchiolitis obliterans organizing pneumonia, causes?
Idiopathic, infections, toxic exposures, drug reactions, autoimmune disease.
HRCT features of bronchiolitis obliterans organizing pneumonia?
Patchy or nodular consolidation, Patchy or nodular ground-glass opacity, Peripheral and peribronchial distribution.
Chronic eosinophilic pneumonia?
Filling of alveoli by mixed inflammatory infiltrate (eosinophils), similar to BOOP--patchy consolidation or ground-glass, peripheral distribution.
Histiocytosis (aka Langerhans histiocytosis or eosinophilic granuloma)?
Centrilobular nodules (may cavitate), Thin-walled, irregular lung cysts, Normal appearing intervening lung, Upper lobe predominance, Spares costophrenic angles.
Lymphangiomyomatosis?
Women of child bearing age, can occur in Tuberous sclerosis, too, Thin-walled, round lung cysts, Normal-appearing intervening lung, Lymph node enlargement, Diffuse distribution without sparing lung bases.
List 4 types of emphysema?
Centrilobular (upper lobes, smokers, most common form), Panlobular (less common, alpha1-antitrypsin, most severe at lung bases), Paraseptal (subpleural lung, adjacent to chest wall and mediastinum), Bullous (Large bullae, young men).
Split pleura sign?
Thickened visceral and parietal pleural layers are split apart and surround an empyema.
Extension of an empyema to involve the chest wall is termed?
empyema necessitatis.
Lung abscess versus empyema CT characteristics?
Abscess (poorly defined, irregular wall, spherical, multiple cavities, acute angles, vessels not displaced), Empyema (well defined, smooth, uniform wall, elliptical, split pleura, acute or obtus angles, vessels displaced).
CT features of a malignant effusion?
Nodular pleural thickening, pleural thickness > 1 cm, concentrically involves the pleura, encasing the lung, thickening of mediastinal pleura.
CT findings for chest wall invasion?
Extensive contact between tumor and chest wall (> 3cm or ratio > 0.7), Obtuse angles, Chest wall mass, Bone destruction
What passes through the aortic hiatus?
Aorta, azygos, hemiazygos, thoracic duct, intercostal arteries, splanchnic nerves.
What passes through the esophageal hiatus?
Esophagus, vagus nerve, small blood vessels.
Anterior mediastinal node groups?
Internal mammary nodes, Paracardiac nodes, Prevascular nodes.
Middle mediastinal node groups?
Pretracheal or paratracheal nodes, Aortopulmonary nodes, Subcarinal noes, Peribronchial nodes.
Posterior mediastinal node groups?
Paraesophageal nodes, Inferior pulmonary ligament nodes, Paravertebral nodes.
Upper limits of normal for subcarinal lymph node diameter?
1.5 cm
Egg-shell calcified mediastinal lymph node, differential?
Silicosis, Coal worker's pneumoconiosis, Sarcoidosis, Tuberculosis.
Calcified mediastinal lymph node, differential?
Prior granulomatous disease (TB, histo, fungal, sarcoidosis), Silicosis, Coal worker's pneumoconiosis, treated Hodgkin's disease, Metastasis
Mediastinal lymph node enhancement?
Castleman's disease, Angioimmunoblastic lymphadenopathy, Vascular metastases, TB, Sometimes sarcoidosis.
Left upper lobe cancers involve what mediastinal lymph node group?
Aortopulmonary window nodes
Lower lobe lung cancers involve what mediastinal lymph node group?
Subcarinal nodes
Resectability non-small cell lung cancer stages?
Stage IIIb-IV, contralateral lymph nodes are N3, unresectable
Sarcoidosis thoracic adenopathy features?
Symmetric hilar adenopathy, Lymphoma is typically asymmetrical.
Prevascular space tumors?
4Ts: thymoma, teratoma, thyroid tumor, terrible lymphoma. Other germ-cell tumors, parathyroid masses, lymphangioma
Castleman's disease
aka angiofollicular lymph node hyperplasia Focal form (Enhancing hilar or mediastinal lymph nodes) Diffuse form (Enhancing mediastinal, hilar, axillary, abdominal, and inguinal node)
CT features of thymoma?
Prevascular or paracardiac location, Typically unilateral, Calcification or cystic degeneration can be present
Thymic masses?
Thymoma, thymic carcinoma, thymic carcinoid tumor, thymolipoma, thymic cyst thymic hyperplasia and rebound (after cessation of chemotherapy)
Three main categories of germ-cell tumors?
1. Teratoma and dermoid cyst, 2. Seminoma (radiosensitive), 3. Non-seminomatous germ-cell tumors (poor prognosis: choriocarcinoma, endodermal sinus tumor, mixed tumors).
Teratoma versus dermoid cyst?
Teratoma contains ecto-, meso-, and endodermal origins (can be cystic, contain fat, have fat-fluid level, or calcify). Can be mature or immature (malignant). Dermoid cyst primarily from epidermal tissue.
Lymphangioma types?
Simple--small, thin-walled with connective tissue. Cavernous--dilated lymphatic channels. Cystic--hygromas, single or multiple cystic masses filled with serous or milky fluid.
Saber-sheath trachea features?
Narrowed lateral dimension of intrathoracic trachea. COPD, repeated trauma from coughing
Concentric tracheal narrowing causes?
Intubation, Polychondritis, Wegener's granulomatosis, Amyloidosis, Tracheobronchopathia osteochondroplastica
Bronchogenic and esophageal duplication cyst features?
Anomalous budding of foregut. Most commonly within subcarinal space. Esophageal duplication cyst indistinguishable from bronchogenic, except they always contact the esophagus
Paravertebral neurogenic tumor divisions?
1. Peripheral nerve or nerve sheath (neurofibroma, neurilemmoma--young adults). 2. Sympathetic ganglia (ganglioneuroma, neuroblastoma--children). 3. Paraganglionic cells (pheochromocytoma, chemodectoma).
Most common cause of posterior mediastinal mass in patients with neurofibromatosis?
Meningocele
Granulomatous mediastinitis causes?
Histoplasmosis, TB, Sarcoidosis, Chronic mediastinal lymph node enlargement with fibrosis. Calcification of lymph nodes common
Sclerosing mediastinitis versus granulomatous mediastinitis
Similar but no calcification with sclerosing mediastinitis.
Pericardial cyst features?
60% anterior right cardiophrenic angle, 30% left cardiophrenic angle, 10% occur higher in mediastinum.
Morgagni hernia features?
Anteromedial diphragmatic foramen of Morgagni. Cardiophrenic angle mass, 90% occur on right. Usually contains liver or omentum.
Right upper lung lobe segments?
Apical Posterior Anterior
Left upper lung lobe segments?
Apicoposterior Anterior Superior lingula Inferior lingula
Right middle lung lobe segments?
Medial Lateral
Right lower lung lobe segments?
Superior Anterior Medial Lateral Posterior
Left lower lung lobe segemnts
Superior Anteromedial Lateral Posterior
Egg-shell calcification of thoracic lymph nodes?
Silicosis, Sarcoidosis, TB
Pulmonary agenesis versus pulmonary aplasia?
Aplasia has rudimentary bronchus.
Pulmonary arteriovenous fistula features?
Single dilated vascular sac or tangle of dilatated tortuous vessels. Mostly subpleural, Rapid enhancement and rapid washout.
Pulmonary sequestration features?
Cystic or solid, Majority left posteromedial lung. All have anomalous systemic arterial supply
Intralobar sequestration versus Extralobar sequestration?
Intralobar: diagnosed in adults, recurrent or chronic infection, region of hyperlucent lung, cystic or multicystic structure with air-fluid levels, consolidated or collapsed lung. Extralobar: diagnosed in infants or children, almost always solid mass that rarely contains air. Venous drainage usually via systemic veins.
Hypogenic lung sydrome (scimitar)?
almost always on right side, hypoplasia of lung, hypoplasia of ipsilateral pulmonary artery, Anomalous pulmonary venous return (scimitar vein) to vena cava or right atrium. Anomalous systemic arterial supply to portion of hypoplastic lung
Extraperitoneal space communicates with?
Retroperitoneal space, retropubic space of Retzius continuous with posterior pararenal space and extraperitoneal fat of abdominal wall.
Perineum
Lies below pelvic diaphragm, includes ischiorectal fossa
Normal fertile ovary dimensions?
2 x 3 x 4 cm.
Bladder carcinoma CT features?
Focal thickening of bladder wall, Weakly enhancing mural nodule, Calcifications 5%, Perivesical fat spread, Pelvic lymph nodes > 10 mm
Uterine leiomyoma CT features?
40% of women > 30 yo, homogeneous, heterogeneous masses, hypodense,isodense, or hyperdense, dystrophic, mottled calcifications, cystic degeneration
Carcinoma of cervic features?
SCC 85%, ADCA 15%, hypo or isodense to normal cervix, Pelvic fluid collections, Direct extension (thick irregular tissue strands), Enlarged lymph nodes > 10 mm
Endometrial malignancy features?
hypodense mass within endometrial cavity, surgical staging method of choice, Enlarged pelvic lymph nodes > 1 cm
Ovarian cancer features?
cystic 66%, bilater 25%, Nonfunctional 85%, Cystic with thick, irregular walls and internal septations. Peritoneal implants, Ascites, Omental cake (irregular, thick greater omentum), follow gonadal lymphatics
Normal ovarian follicle size?
<3 cm
Functional ovarian cyst features?
Benign follicular or corpus luteum cysts, well-defined, thin walled, < 3 cm
PID CT features?
Thickening of fallopian tubes (early), Enlargement and abnormal enhancement of ovaries, Dilated fallopian tubes filled with high-density fluid (advanced-pyosalpinx), Complex adnexal fluid collections (abscess).
Adnexal torsion, CT features?
Most cases involve mass (benign cystic teratoma, hydrosalpinx, functional cyst), Thickening fallopian tube wall, ascites, deviation of uterus to affected side
Testicular cancer lymph node involvement?
Gonadal lymphatics (testicular veins and renal hilar nodes), external iliac chains to para-aortic nodes. Inguinal nodes involved only when scotrum invaded.
Aberrant right subclavian artery?
Left arch, last branch (diverticulum of Kommerell), courses behind esophagus
Two types of right aortic arch?
Right arch with aberrant left subclavian, Mirror image right arch (almost always associated with congenital heart disease).
Double aortic arch?
Vascular ring with dysphagia, no innominate artery (subclavians and carotids come off separately)
Ascending aortic aneurysm causes?
atherosclerosis, Marfan's syndrome, cystic medial necrossi, syphilis, aortic valvular disease
3 common locations for aortic trauma?
Aortic root level of ligamentum arteriosum diaphragm and aortic hiatus
Stanford aortic dissection types?
Type A--involves ascending aorta (treated surgically: possibility of retrograde dissection and rupture within pericardium or occlusion of coronary or carotid arteries), Type B--Do not involve arch, arise distal to left subclavian artery (treated medically).
DeBakey's aortic dissection types?
Type I--entire aorta, Type II--ascending aorta only, Type III--descending aorta only
Three mediastinum compartments?
supra-aortic mediastinum, subaortic mediastinum, paracardiac mediastinum
Mediastinal spaces and recesses?
Pretracheal space, Prevascular space, Superior pericardial recess, Azygoesophageal recess, Subcarinal space
Persistent left superior vena cava features?
Failure of cardinal vein to regress, Lateral to left common carotid artery, enters coronary sinus posterior to left atrium.
Azygos or hemiazygos continuation of IVC?
Hemiazygos (polysplenia), Azygos (asplenia), dilated azygos, hemiazygos systems, Diaphragmatic IVC drains hepatic veins only.
Causes of SVC syndrome?
Most commonly bronchogenic carcinoma, sarcoidosis, fibrosing mediastinitis, tuberculosis, mediastinal radiation.
Pulmonary artery diameter in pulmonary hypertension?
>3 cm, or > ascending aorta
Difference in pulmonary dilatation in pulmonary hypertension and pulmonic stenosis?
Pulmonic stenosis--main and left pulmonary arteries dilated. Pulmonary hypertension--mian, left, and right pulmonary arteries dilated.
Acute PE versus chronic PE at CT?
acute PE--clot centered in lumen, outlined by contrast [doughnut sign (cross section) and railroad track sign (same plane)], Chronic PE--clot adherent to wall, located peripherally.
Acute pancreatitis CT findings?
Enlargement decrease in density blurring of margins peripancreatic stranding blurring of fat planes thickening of retroperitoneal fascia
Complications of acute pancreatitis?
Fluid collections Pseudocysts Necrosis (lack of enhancement) Phlegmon (mass of edema and inflammation) Abscess Hemorrhage Pseudoaneurysms Thrombosis (splenic vein) ascites
Chronic pancreatitis features?
Causes (alcohol, autoimmune, tropical pancreatitis) Calcifications 50% Atrophic Duct strictured and dilated segments, "beaded" Pseudocysts
CT features of pancreatic adenocarcinoma?
hypodense mass 96% head > body > tail
Signs of pancreatic adenocarcinoma resectability?
Isolated pancreatic mass Double duct sign without mass
Signs of pancreatic adenocarcinoma unresectability?
Involvement of major arteries or veins. Extension of tumor beyond margins of pancreas, invasion of adjacent organs, Ascites (presumtive peritoneal carcinomatosis)
Appendicitis CT features?
Distended appendix >6 mm, enhancing thickened walls, appendicolith within phlegmon or abscess
Differential of RLQ pain without abnormal appendix or appendicolith?
Crohn's disease, cecal diverticulitis, perforated cecal carcinoma, mesenteric adenitis, PID
Complications associated with perforated appendicitis?
Phlegmon (periappendiceal soft-tissue mass), abscess (> 3cm surgical or catheter drainage).
Mucocele of appendix?
Distended, mucus-filled appendix without inflammation. >2 cm, usually caused by mucinous neoplasm
Diverticulitis CT features?
Small, round collections of air, feces, or contrast, wall thickening, hyperemic enhancement, sinus tract or fistual formation, Abscess formation
Colitides?
Ulcerative colitis, Crohn's colitis, Pseudomembranous colitis, Typhlitis, Ischemic colitis (splenic flexure, rectosigmoid) Radiation colitis, Infectious colitis, Toxic megacolon
CT features of islet cell tumors?
Small tumors (<4 cm) enhance. Large tumors heterogeneous with calcification, cysts, necrosis, vascular invasion, tumor extension (generally nonfunctioning)
Functioning islet cell tumors' malignant potential?
80% glucagonoma 60% gastrinoma 10% insulinoma
CT features of pancreatic lymphoma?
Focal tumor, homogeneous and weakly enhancing. Diffuse infiltrative tumor resembles pancreatitis. Peripancreatic lymphadenopathy. No or minimal dilatation of pancreatic duct. Lymphadenopathy below renal veins in lymphoma but not in pancreatic adenocarcinoma?
Metastases to pancreas CT features?
Round or ovoid Most heterogeneous, can be diffuse, solitary, or multiple nodules
Intraductal papillary mucinous neoplasm CT features?
Diffuse or segmental dilation of pancreatic duct, atrophy of pancreas, cystic ectasia of branch ducts "bunch of grapes", intraductal papillary solid mass, multicystic mass.
Pseudocyst CT features?
Most common cystic lesion in and around pancreas, low-density collections of fluid, debris, or blood, Distinct walls with occasional calcifications, Generally unilocular, Signs of pancreatitis usually present.
Pancreatic mucinous cystic neoplasm CT features?
Middle-aged women, Multiloculated cysts, 6 or less cysts > 2 cm are typical, May have calcifications, Most common in tail, Do not communicate with pancreatic duct.
Pancreatic serous cystadenoma CT features?
Benign, well-circumscribed mass of innumerable small cysts. May have central stellate scar with central calcification. With larger cysts may have honeycomb appearance, Unilocular form indistinguishable from mucinous cystic neoplasms.
Splenic cysts?
Posttraumatic cyst (most common), Congenital epidermoid cyst, Echinococcal cysts, Pancreatic pseudocyst.
Splenic microabscesses CT features?
Multiple low-density lesions, differential: lymphoma, kaposi's sarcoma, sarcoidosis, metastases.
Most common neoplasm of spleen?
Hemangioma
Rare primary malignancy of spleen?
Angiosarcoma
Multiple small focal splenic calcifications?
Histoplasmosis or TB.
Features of esophageal carcinoma?
Lack of serosa, early spread, poor prognosis. 90% SCC 10% ADCA (Barrett's) Irregular wall thickening >3 mm Intraluminal polypoid mass Eccentric narrowing of lumen Proximal dilatation Metastases to lymph nodes and liver
Esophageal leiomyoma features?
Smooth, well-defined mass. Eccentric wall thickening, Leiomyosarcoma (heterogeneous, ulcerate)
Esophageal varices, CT features?
Well-defined, enhancing nodular and tubular densities adjacent to esophagus
Esophagitis causes?
Candida, herpes simplex, cytomegalovirus, TB
Paraesophageal hernia?
Gastric cardia and gastroesophageal junction below esophageal hiatus, Fundus of stomach above hiatus, adjacent to distal esophagus
Gastric hernia rotations?
Organoaxial (long axis rotation). Mesenteroaxial (upside down stomach)
Gastric varcies without esophageal varices?
hallmark findikng of splenic vein thrombosis.
Small bowel malignant tumors?
Lymphoma (masses, nodular wall thickening), Hematogenous metastases (melanoma, breast lung, RCC), Carcinoid (appendix, mesenteric small bowel, fibrosing reaction) Adenocarcinoma (duodenum) Leiomyosarcoma (large, exophytic, necrosis)
Crohn's disease CT features?
Terminal ileum 80%, Circumferential thickening (target and double halo), Marked wall enhancement, "comb sign" hyperemic vasa recta, Segmental strictures, Skip areas, Fistulas and sinus tracts, abscesses.
Complete mechanical SBO?
Dilatation of SB > 2,5 cm, distinct transition zone
Paralytic ileus?
Dilatation of distal and proximal SB without transition zone
Partial mechanical SBO?
Transition zone less distinct, small bowel feces
Sclerosing mesenteritis features?
Inflammatory disorder of unknown cause, chronic inflammation, fat necrosis, fibrosis, misty mesentery
Cystic mesenteric masses?
Cystic lymphangiomas, Cystic mesothelioma (rare, benign tumor) cystic teratomas (fat, calcification)
Mesenteric neoplasms?
Lymphoma (most common), Metastases (more common than primary tumors), Mesenteric fibromatosis (desmoid tumor), GISTs (large, hemorrhage, necrosis) Sarcomas (leiomyosarcoma, fibrosarcoma, malignant fibrous histiocytoma,liposarcoma)
Colon volvulus types?
Sigmoid volvulus (most common, mesenteric whirl), Cecal volvulus, Cecal bascule (folding rather than twisting of cecum)
Fibrolammelar Carcinoma CT features?
Large mass in healthy liver Enhances prominently and heterogeneously Central scar Difficult to distinguish from FNH
Liver lymphoma CT features?
Diffuse infiltration, Well-defined, homogeneous low-density nodules, Numerous small nodules resembling microabscesses
Hepatic adenoma CT features?
Young women on oral contraceptives. Men on anabolic steroids. Glycogen storage disease (multiple). Surgical removal for fear of rupture or malignant transformatoin. Unenhanced, isodense to liver. Arterial phase, early homogeneous enhancement. Few Kupffer cells, no sulfur colloid uptake
FNH CT features?
Mini liver central stellate scar and fibrous bands. Unenhanced, isodense to liver. Arterial phase, immediate intense homogeneous enhancement. May have delayed enhancement of scar. Positive sulfur colloid uptake
Cavernous Hemangioma CT features?
Unenhanced, hypodense mass. Arterial phase, peripheral nodules of contrast. Venous phase, progressive filling-in from periphery. Delayed, prolonged enhancement. Small hemangiomas, immediate homogeneous enhancement.
Cystic liver masses?
Hepatic cysts Pyogenic abscess Amebic abscess Hydatid cyst
Normal bile duct measurements?
Intrahepatic ducts 2 mm in central liver. Common duct < 6 mm. Give 1 mm per decade in elderly
CT findings of biliary obstruction?
Dilated intrahepatic biliary ducts, Dilatation of common duct > 7 mm, Gallbladder diameter > 5 cm
Precursors of choriocarcinoma?
Choledochal cyst Primary sclerosing cholangitis Caroli's disease intrahepatic stone disease Clonorchiasis
cholangiocarcinoma CT features?
Intrahepatic mass-forming, homogeneous tumor with irregular borders. Periductal infiltrating lesions grow along bile ducts. Intraductal tumors, polypoid or sessile. Extrahepatic cholangiocarcinoma, duct obstructing tumor
CT features of primary sclerosing cholangitis?
Multiple segmental strictures (beaded appearance) with thickening of bile duct. Complications: obstruction, cholestasis, biliary cirrhosis, cholangiocarcinoma.
Choledochal cyst types?
Type I, cystic dilation of CBD. Type II, CBD diverticulum. Type III, choledochocele, protrudes into duodenal lumen. Type IVa, intrahepatic saccular dilatations. IVb, extrahepatic multiple cystic dilatations. Type V, Caroli's disease.
CT findings of acute cholecystitis?
Gallstones in gallbladder 75%, GB distension > 5 cm, GB wall thickening > 3 mm, Early-phase enhanced GB fossa, Pericholecystic stranding, Air in GB wall (emphysematous)
Gallbladder carcinoma CT features?
Polypoid soft-tissue mass, Focal or diffuse wall thickening, Mass containing stones replaces GB and invades liver.
CT features of lymphoma in abdomen
Multiple enlarged nodes, Coalescence of enlarged nodes to form multinodular masses which may encase vessels, Conglomerate nodal masses
CT features of AIDS in abdomen?
Lymphadenopathy (MAI, lymphoma, Kaposi's), Focal, small low-density liver lesions (TB, Histo, lymphoma, Kaposi) Focal, small low density spleen lesions (MAI,Cocci, candida, PCP, lymphoma) Splenic or LN calcifications (PCP) Nephromegaly with striated nephrogram (HIV nephropathy) Kaposi's sarcoma (adenopathy, hepatosplenomegaly) AIDS-related lymphoma (any solid mass)
Surgical indications for splenic trauma?
Active bleeding, Large nonperfused portions Pseudoaneurysm formation
Cortical rim sign?
Delayed finding. Faint enhancement of kidney periphery in renal infarction. Renal capsule supplied by separate arteries
Complications of pancreatic trauma?
Pseudocyst formation hemorrhagic pancreatitis Abscess Fistula
Shock bowel?
Severe hypotension and hypoperfusion of bowel. Diffuse dilation of small bowel with wall thickening and increased wall enhancement
Extraperitoneal bladder rupture?
Contrast leakage into retropubic space, along abdominal wall, scrotum, thigh, and retroperitoneum.
Intraperitoneal bladder rupture?
Contrast in paracolic gutters and surrounding bowel
Which adrenal gland more susceptible to traumatic injury?
Right adrenal gland. compression of gland between liver and spine.
Liver segment I?
Caudate lobe, Ligamentum venosum and IVC separate it from liver
Liver segments II and III?
Lateral division of left lobe. II-superior. III-inferior.
Liver segments IV?
Medial division of left lobe. IVa-superior. IVb-inferior.
Liver segments V and VIII?
Anterior segments of right lobe. VIII-superior. V-inferior.
Liver segments VI and VIII?
Posterior segments of right lobe. VII-superior. VI-inferior.
Third inflow?
Areas of liver supplied by aberrant systemic veins. Porta hepatis, adjacent to gallbladder, adjacent to fissure of ligamentum teres.
Increased liver attenuation?
Amiodarone Hemochromatosis (secondary form-hemosiderosis, blood transfusions)
Liver nodules in cirrhosis?
Regenerative nodules Dysplastic nodules Small HCC nodules Metastatic disease Hemangiomas
CT features of portal hypertension?
Portosystemic collateral vessels Enlarged portal vein, > 13 mm. Splenomegaly Ascites
CT features of Budd-Chiari syndrome?
Enlarged caudate lobe. Central liver enhances early and peripheral liver enhances late.
Clinically significant liver lesions?
Metastases Hepatoma Hepatic adenoma
Metastases to liver features on CT?
Most common liver malignancy. Most commonly from colon. Target appearance. Hypervascular (carcinoid, choriocarcinoma, pheochromocytoma, RCC, thyroid cancer). Some cystic/nectrotic, calcification
HCC CT features?
50% solitary tumor 30% infiltrative 20% multinodular Small tumors, < 3cm bright homogeneous enhancement Necrosis and calcification common Invasion of hepatic and portal veins
How much must a renal mass enhance in Hounsfield units before it is considered enhanced?
10 - 15 H
Metastatic lymph node size in RCC?
> 2 cm nearly alwasy metastatic 1 - 2 cm indeterminate
Most common sites for RCC metastases?
lungs mediastinum bone liver contralateral kidney adrenal gland brain
Bosniak cystic renal mass categories?
Category I Benign simple cyst Category 2 Benign Complicated Category 3 Indeterminate cystic lesions Category 4 Malignant cystic tumors (enhancing soft tissue)
VHL and TS CNS involvement differences?
VHL--cerebellar, spinal cord, and retinal hemangioblastomas. TS--retinal and cerebral hamartomas
Emphysematous pyelonephritis versus emphysematous pyelitis?
Emphysematous pyelonephritis: diabetes, urinary obstruction, gas in renal parynchema, nephrectomy. Emphysematous pyelitis: gas in pelvis and calyces (trauma, iatragenic, infection), not a surgical urgency.
Renal stone not seen at CT?
Crystallin stones related to indinavir (protease inhbitor HIV Rx)
What size renal stones can pass on their own?
< 4 mm nearly always pass. > 8 mm rarely pass.
Tissue rim sign?
Halo of soft tissue that surrounds ureter stone.
Absence of white pyramids?
Subtle sign of urinary obstruction on affected side.
Phlebolith distinguishers?
tail sign (vein), central lucency, round
Adrenocortical carcinoma features?
large > 5 cm Necrosis and calcification Delayed contrast washout
Adrenal calcification causes?
Children (neuroblastoma, gnaglioneuroma) Adult (adrenal carcinoma, pheochromocytoma, glanglioneuroma, metastases) Wolman's disease (autosomal recessive, enlarged calcified adrenal glands, hepatosplenomegaly)
In adrenal hyperplasia, adrenal limb thickness exceeds?
10 mm
Organ of Zuckerkandl?
Common location for extra-adrenal pheochromoctyoma. Near origin of IMA
Common metastases to adrenal glands?
Lung Breast Melanoma
Lipid-rich adrenal adenoma Hounsfield units?
< 10 H
Lipid-poor adrenal adenoma features?
Non-contrast H > 10 Enhancement washout > 50% 15 minute post-contrast H < 35
Serous ascites attenuation value in H?
-10 to +15
Hemoperitoneum attenuation value in H?
>35, averaging 45 H
With absence of intrahepatic segment of IVC, how does lower body venous blood reach the heart?
Drainage to SVC via azygos system?
Aneurysmal diameters of abdominal aorta and iliac arteries?
AAA > 3 cm Iliac aneurysm > 1.5 cm
Hyperattenuating crescent sign?
Crescent area of high attenuation (dissecting contrast) within wall or intraluminal thrombus of AAA, impending rupture
Beak sign in distinguishing true lumen from false lumen in aortic dissection?
Intimal flap and false lumen wall create an acute angle: beak sign
Dilatation of vein at site of DVT means acute or chronic?
Acute
Abdominal and retrocrural lymph node pathologic size cutoff?
Abdominal LN > 10 mm. Retrocrural LN > 6 mm