4. Breast p150-156 (MRI, Risk) Flashcards
Breast MRI - technique (4)
Patient lies on stomach, breasts hanging through holes in the table.
Sequences include T2, pre and post dynamic contrast fat sat T1.
Fat sat is important, as breasts contain a lot of it.
Dynamic imaging done to look at washout curves, like prostate MRI.
Breast MRI - reading basics (6)
Assess background uptake
- Hormone changes with menstrual cycle change how much contrast is taken up, less early and more later on
Look for masses
- MIP is helpful, like looking for lung nodules.
- Most T2 things are benign (nodes, cysts, fibroadenoma)
- If not T2 bright, is it spiculated, a mass, is it new?
Washout curve
- Malignant morphology is more important than benign curve
New masses get biopsy. non mass like enhancement gets biopsy if new.
T2 bright is benign.
MRI - parenchymal enhancement (4)
It’s normal.
Commonest in posterior breast, upper outer quadrant, during the lateral part of the menstrual cycle (luteal phase, day 14-28).
Reduced by performing MRI during days 7-14.
Tamoxifen decreases background parenchymal uptake, then causes a rebound
MRI - Foci (3)
Defined as round or oval, circumscribed and <5mm.
Usually not high risk, 2-3% malignant.
Ill defined borders or suspicious enhancement should be biopsied.
NMLE (non mass like enhancement) (3)
Not a mass, a clump of tissue enhancement.
Can be segmental (triangular, pointing at the nipple, indicates single branch), regional (bigger triangle) or diffuse.
Heterogenous enhancement of NMLE is most sus.
Masses on MRI (3)
Defined as 5mm or larger.
Irregular shape, spiculated margins, heterogenous or rim enhancement are concerning and need biopsy.
Morphology is more important than kinetics.
Kinetics (MRI) (5)
2 portions of kinetics graph
1 - initial upstroke (first 2 mins, can be rapid, medium, slow)
2 - washout portion (2-6 mins), graded either continued rise (type 1), plateau (type 2) or rapid washout (type 3).
RIsk of cancer
- Type 1: 6%
- Type 2: 7-28%
- Type 3: 29% +
Classic looks on MRI (4)
Fibroadenoma: T2 bright, round, non-enhancing septa, type 1 curve
DCIS: Clumped, ductal, linear or segmental NMLE. Kinetics usually not helpful.
IDC: Spiculated irregular masses, heterogenous enhancement, type 3 curve.
ILD: doesn’t always enhance
T2 bright lesions on MRI (2)
Usually T2 bright = benign. Cysts, Lymph nodes, Fat necrosis, Fibroadenoma.
Exception is Colloid cancer and mucinous cancer which can be T2 bright.
Breast Ca MRI trivia (2)
Known breast Ca: 0.1-2% have contralateral Ca on mammogram. 3-5% on MRI.
Spiculated margins = 80% malignancy. Single most predictive feature of malignancy.
Oestrogen related risk (6)
More oestrogen exposure = more breast cancer risk. E.g.
- Early menarche
- Late menopause
- Late first pregnancy/no children
- Obesity
- Alcohol
- Hormone replacement
Other breast cancer risk factors (4)
Any of the high risk lesions mentioned earlier (ADH, ALD, LCIS, Radial scar, Papilloma) will increase risk
Density - medium risk, dose dependent (denser breasts = more risk)
Chest wall radiation: Usually in lymphoma patients. Big risk, especially in young age.
- Risk peaks around 15 years post treatment.
- If child has >20Gy to the chest, qualifies for annual screening MRI (from age 25 or 8 years after exposure, whichever is later)
Relatives with cancer: First degree relative increases lifetime breast cancer risk from 8% to 13%. 2 first degree relatives = 21%
Breast cancer mutations (6)
BRCA 1 - chromosome 17, more common than BRCA 2. Increased risk for breast, ovary, various GI cancers
BRCA 2 - Chromosome 13, male carriers have higher risk. Increased risk of breast, ovary, various GI cancers.
Li Fraumeni - p53 doesn’t work, high risk for many rare cancers
Cowden syndrome - Risk of breast cancer, follicular thyroid cancer, endometrial cancer and Lhermitte-Duclos (a brain hamartoma)
Bannayan-Riley Ruvalcaba - associated with developmental disorders at young age
NF-1 - moderate risk of breast cancer
