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45 Cards in this Set

  • Front
  • Back
X-Ray Radiographs
- what factors determine the density of an image?
- composition (atomic number)
- thickness of the object
- strength of the x-ray
What are the 4 basic radiographic densities (colors) represented on a film?
Air = black
Fat = dark gray/black
Water (soft tissue - organs, muscles, blood vessels, masses) = light gray
Bone, calcium, metal = white
What contrast agents are used in x-rays?
How are they introducted?
What color do they show up on films?
Barium - ORAL
Iodinated contrast - IV

*Show up white!
What is Computed Radiography (CR)?
Where are the images stored?
Instead of a film, a phosphor plate is exposed to the x-rays --> light released is converted into an electron stream --> converted by a computer into a digital image, available over networks

- Images stored in PACS (picture archiving and communication system)
How is an Ultrasound image created?
Transducer sends high frequency sound (1-20 megahertz) into body --> gathers the echoes --> converts into electronic signals displayed on monitor

- whatever the waves reflect off of appears white... sound waves go through fluid, which appears black
What are the advantages of US?
- non-invasive
- no radiation (great for pregnancy)
- relatively inexpensive and widely available
- portable machines
- good contrast of tissue layers in many organs - e.g., see follicles within ovaries
- multiplanar imaging in REAL TIME
What are the disadvantages of US?
- relatively small field of view
- air-filled structures and bone cannot be evaluated; obesity ruins sound beam
- operator-dependent! reproducibility is bad
- deeper penetration = lower frequency beams and lower-resolution
What is Sonohysterography?
Saline injected into endometrial cavity before US --> improves quality and contrast bc fluid is excellent for US

- good for eval of endometrial cavity
- bad for eval for tubal disease (need contrast agents that arent FDA approved)
How does one create a 3D US?
4D?
3D: US beam is sent at multiple different angles and collected in different data sets --> computer puts it all together

4D: adds movement!
What is Doppler?
- what type of pelvic dx is it good for?
special form of US used to evaluate BLOOD FLOW - presence, character, speed, direction

- can be used to evaluate vascularity and type of blood flow in mass (high/low resistance)
- helps to dx ovarian torsion
What is CT/CAT?
What is used to improve contrast?
= Computer Tomography/ Computer-Assisted Tomography

To improve contrast:
- suspended respiration to minimize motion
- iodinated contrast
- oral contrast to opacify bowl loops
- thin patients better - obesity degrades quality
What are the advantages of a CT?
- large field of view - encompasses all structures in iamge from skin-to-skin
- high resolution with clear anatomy
- less operator-dependent; more reproducible
- ultra-fast!
What are the disadvantages of CT?
- exposure to ionizing radiation
- relative lack of soft tissue differentiation - exc calcification or lots of fat
- potential adverse rxn to contrast medium
- reconstruction of images into multiplanar view takes time- not immediately available
What is a PET-CT?
- Use?
- Disadvantages?
Positron Emission Tomography + Computed Tomography
- uses F-18 (radioactive tracer) attached to FDG (glucose-like) molecule
--> accumulates in malignant cells bc high rate of glucose metabolism

**More sensitive than each of its components separately

- Used to stage tumors and monitor responses to therapy

- Disadvantages: high radiation exposure; EXPENSIVE
MRI
- how does it work?
- possibly planes of images?
- contrast agent?
- radio waves 10,000-30,000 x stronger than earth's magnetic field are passed thru body --> forces hydrogen nuclei into different position --> as they move back into place, send out their own radio waves

- planes: coronal, axial, sagittal all possible

- Gadolinium = contrast agent (low allergy rate)
Advatages of MRI?
- large field of view from skin-to-skin
- no exposure to ionizing radiation
- not as operator-dependent as US; more reproducible
- the best soft-tissue contrast resolution!!!!! - including fat and hemorrhage
Disadvantages of MRI?
- artifacts from respiratory motion and bowel peristalsis
- EXPENSIVE
- time-consuming with complicated protocols
- Gadolinium contraindicated in patients with renal failure
- limited access
- claustrophobia
- tight squeeze for obese pts
- need to understand the physics involved
In what patients is Gadolinium contraindicated? Why?
RENAL FAILURE:
Increased risk of NSF = Nephrogenic Systemic Fibrosis
- potentially fatal disease resulting in multiorgan fibrosis

PREGNANCY:
Cross the placenta
Which technique offers the BEST soft-tissue contrast resolution?
MRI
For what patients is it contraindicated to enter the MRI magnet?
- ferromagnetic metallic objects/implants - e.g., cochlear implants, pacemakers, neuro stimulators, brain aneurysm clips, shrapnel, etc.

- Orthopedic devices are ok, but cause artifacts on image

- IUDs are fine
What is the main use of plain film radiographs in women's imaging?
delineation of large pelvic mass, detection of calcification
What is HSG?
- Use?
- MOA?
- when should it be performed?
= Histosalpingography
- used in work-up of infertility

- MOA: radioopaque iodinated contrast material injected into uterine cavity thru cervix, then out fallopian tubes -- to assess patency of tubes and delineate uterine cavity

- best performed during proliferative phase after period bc must avoid pregnancy (iodinated contrast) - approx day 6-10 of cycle
What are the main complications of HSG?
cramping, pain, bleeding, infection, allergic rxn to contrast material, embolizations of air or contrast medium (**esp if oil-based medium is used; now usually use water-based)
What is the imaging modality of choice for evaluating female pelvis/pregnancy??
= FIRST TEST ORDERED FOR GYN SX???
Ultrasound!!!
What are the 2 methods of performing an ultrasound of the female pelvis?
Compare the two...
Transabdominal Sonography (TAS)
- full bladder (discomfort)
- larger field of view
- structures displaced deeper by bladder--> less resolution
- bladder pushes bowel loops out of the way, which allows for general pelvic overveiw
- from outside abdomen, so can do mult scan planes and move transducer around; patient can move around

Transvaginal Sonography (TVS)
- empty bladder
- smaller field of view
- closer structures--> better resolution
- limited mobility of transducer
- vaginal narrowing can be a problem
What is the earliest that an ultrasound can detect evidence of pregnancy?
- what else can be seen in the first trimester? when?
Earliest Detection = Gestational Sac = 4.5 weeks
Yolk Sac = 5.5 weeks **definitive sign
Embryo = 6 weeks (2-3 mm length)
Heart Beat = 6 weeks (Crown Rump Length - CRL = 5 mm)
Gross Body Movements = 9 weeks
What type of Ultrasound can detect images earlier??
TVS can confirm structures 1-2 weeks earlier than TAS
How many vessels are within the umbilical cord?
2 arteries
1 vein
What is the classic triad of findings of an ectopic pregnancy?
1. abdominal pain
2. vaginal bleeding
3. adnexal mass
What does the density of a mass indicate about its malignancy?
What else?
The more solid a mass, the more malignant...
Also, septations and ascites are bad signs
What imaging method is best for TRAUMA??
CT!!!
What is the relationship between CT scan and pregnancy?
AVOID! Use only in dire situations bc ionizing radiation is harmful
What is the "problem solver" imaging device- used when there are unusual findings in female pelvis?
MRI!!!

= adjunctive test
What is the method of choice for staging cervical, uterine, vulvar, and vaginal carcinoma?
MRI!
Is MRI safe for pregnancy?
Considered safe.
Avoided during first trimester bc rapid organogenesis and limited results of imaging this early
What is the imaging modality of choice for BREAST evaluation?
x-ray mammography
What are the recommendateions for the frequency of mammography screening?
- Every year after age 40
- If first-degree relative with (premenopausal) breast cancer, screen yearly as early as TEN YEARS before
- Don't generally use on women <30 bc increased sensitivity to radiation in immature breast
What are the American Cancer Society guidelines for the average woman's breast cancer screening?
1. Monthly self-breast exam
2. Yearly physical exam by health professional
3. Annual mammogram after 40
What is the difference between screening mammography and diagnostic mammography?
Screening mamm = small amount of radiation, 2 views per breast

Diagnostic mamm = used to target a specific finding at another screening - e.g., clinical finding, symptom, screening mammography
What is the recall rate after a screening mammography?
What is the positive predictive value of mammography?
Recall Rate = 10%
PPV = 15-35% (# cancers diagnosed per # biopsies recommended)
What are the routine views for breast mammography?
- craniocaudal (CC: top-bottom)
- mediolateral oblique (MLO: side-side)
What does the ability of a mammogram to detect cancer depend on?
- density of breast tissue
- size of tumor
- skill of radiologist
What is the sensitivity of mammography?
= 75% (less under 40 y.o. bc of denser breasts and faster growing tumors; better over 65 y.o.)
What is the most common adjunctive method for breast imaging?
What else might be used?
ULTRASOUND = #1 adjunctive
- differentiate cyst from solid
- differentiate benign from malignant
- guide biopsy
- possibly use first for women <30 with palpable mass

Contrast enhanced breast MRI is not as popular as US
- differentiate post-surg scar from tumor
- ***for silicone IMPLANTS
- staging of known cancer
- ambiguous mammography, sonography, clinical findings
- **screening of women with >20% risk of br cancer - BRCA mutation or history of mediastinal irradiation in adolescence
What are the 2 molecular imaging techniques being studied for breast cancer research?
BSGI = breast specific gamma immaging
PEM = positron emitting mammography