Describe fibroglandular tissue and background parenchymal enhancement, then each lesion as a focus, mass or non-mass enhancement with its kinetic curve and diffusion — for high-risk screening, extent of disease, and implant or occult-primary questions.
Orient first
- Indications: high-risk screening (BRCA, lifetime risk ≥ 20%), local staging, neoadjuvant response, occult primary, implant rupture.
- Schedule premenopausal women in days 7–14 of the cycle to reduce background enhancement.
- Type 3 (washout) kinetics and restricted diffusion raise suspicion; persistent (type 1) favours benign — but morphology comes first.
Acquire the study
- Prone breast coil: T2 (or STIR), DWI, pre-contrast fat-saturated T1, dynamic post-gadolinium T1 (first post-contrast at ~60–90 s), subtractions and MIP.
The manoeuvre
- Fibroglandular tissue amount (a–d) and background parenchymal enhancement (minimal to marked).
- MIP and subtractions: each lesion — focus (< 5 mm), mass (shape, margin, internal enhancement) or non-mass (distribution, internal pattern).
- Kinetics: initial phase (slow/medium/fast) and delayed phase (persistent, plateau, washout).
- T2: bright masses favour fibroadenoma or lymph node; DWI: ADC in the lesion.
- Extent in mm, multifocality/multicentricity, nipple, skin, pectoralis, chest wall; axillary nodes.
What confirms it
- A suspicious morphology with supportive kinetics or restriction — biopsy (MRI-guided if not seen on second-look ultrasound).
What licenses you to exclude it
- A normal MRI in a high-risk woman does not remove the need for continued screening.
The classic misread
- Calling marked background enhancement non-mass enhancement.