Breast Imaging
Breast Imaging
This domain tests mammographic interpretation, breast ultrasound, MRI, BI-RADS assessment, and screening/staging decisions. Calcification morphology and lesion management are high-yield.
Core rules
- BI-RADS: 0 incomplete, 1 negative, 2 benign, 3 probably benign (<2% malignancy, short-interval follow-up), 4 suspicious (4A low, 4B moderate, 4C high), 5 highly suggestive (>95%), 6 known biopsy-proven malignancy.
- Calcifications: benign are typically round, diffuse, or large rod-like; suspicious are clustered pleomorphic, fine-linear, or branching. Distribution matters.
- Ultrasound: irregular shape, nonparallel orientation, spiculated margins, and shadowing favor malignancy. MRI kinetics: rapid initial rise with washout is suspicious; persistent enhancement favors benign.
- Screening reduces mortality; dense breasts may need supplemental ultrasound or MRI based on risk.
Worked example
A 55-year-old has a screening mammogram showing a 1.5 cm cluster of pleomorphic microcalcifications in the upper outer quadrant. This is BI-RADS 4B or 5; stereotactic vacuum-assisted biopsy is indicated. If the calcifications were diffuse and round, BI-RADS 2 would be appropriate.
Traps
Calling benign secretory calcifications malignant; assigning BI-RADS 3 to a palpable or new lesion; missing architectural distortion; ignoring axillary lymphadenopathy; overusing MRI without a defined indication.