PENIS

• High risk screening (MRI in conjunction with mammography)

  • >20% life time risk

  • BRCA 1 & 2

  • Li-Fraumeni, Cowden, Bannayan-Riley-Ruvalcaba syndromes + 1st degree relative

  • Prior h/o radiation to the chest before age 30 yo

• Extent of disease

  • Most premenopausal women with CA diagnosis

    • Usually not needed for small lesions seen on US

  • Evaluates for: 

    • More accurate size of lesion

    • Satellite lesions (multifocal vs multicentric dz)

    • Invasion of skin, nipple, pectoralis

    • Contralateral breast dz

    • LNs

• Neoadjuvant FU

  • Assess response to therapy

• Problem solving

  • Axillary mets with normal mammogram

  • Difficult location of lesion possibly not amenable to bx

  • Vague finding / difficult to bx

• Evaluate silicone implant integrity

  • If performed without contrast, no BIRADS assessment category should be assigned bc cannot confirm lack of malignancy without contrast.

  • FDA recommends MRI evaluation q 2 yrs

• CURRENTLY NOT ACCEPTED RECOMMENDATIONS

  • Hetero or extremely dense breasts

  • Borderline high risk

• Clinical hx / reason for exam

  • High risk screen (why?)

  • Extent of dz

  • Implant integrity

  • Problem solving 

  • H/o breast CA

• Comparison studies: mammo, US, MRI

• Timing:

  • Optimal timing is 7-10 days after LMP. Otherwise, BPE may be too pronounced and decrease sensitivity/specificity

  • DO NOT delay if there is a cancer diagnosis

• Reported as 4 categories:  Minimal (includes no enhancement), mild, moderate, marked 

  • Higher BPE = more difficult to read

  • Can vary based on menstrual cycle

• Symmetric vs asymmetric

  • If asymmetric, check for prior radiation therapy or lumpectomy

• Assessed on initial post contrast and/or post processed MIP

• Subjective (volume and intensity)

• Factors that can influence BPE:

  • Increase: HRT, lactation

  • Decrease: SERMs, Tamoxifen (rebound)

• Significance:

  • Common, physiologic

  • Spectrum of patterns 

    • HRT, lactation, menstural cycle, tamoxifen

  • Asssociation with breast CA risk

SUBTRACTION

• Data derived from pre is subtracted from dynamic to give an image showing pure enhancement

• Motion can degrade

• Mass is a 3D space occupying lesion >5 mm with convex margins  

• Can be solid, cystic, or both

• Mass characteristics: shape, margin, internal enhancement, kinetics

• SUSPICIOUS MASS FEATURES!

  • Shape - irregular

  • Margin - irregular, spiculated

  • Internal enhancement - homogeneous, heterogeneous, rim (irregular/thick)

• Round = spherical

• Oval = up to 3 gentle lobulations

• Irregular = uneven (BAD)

• Assessment of margins is the most reliable feature to determine benign vs malignant. 

• MORPHOLOGY TRUMPS KINETICS

• Types:

  • Circumscribed (benign)

  • Not circumscribed

    • Irregular (BAD)

    • Spiculated (BAD)

• Homogeneous - confluent, uniform enhancement (BAD)

• Heterogeneous - non-uniform enhancement w/ variable SI (BAD)

• Rim enhancing - pronounced peripheral enhancement (cysts or necrotic masses) (BAD)

  • Thin uniform around T2 bright mass -> pericystic inflammation 

  • Thick irregular or nodular -> necrotic Ca

• Dark internal septations - dark, nonenhancing lines w/n a mass

  • Suggestive of FA

  • As an isolated feature, NPV is insufficient to exclude malignancy

  • Useful if supported by other present features

• NME is not a focus or a mass but is discrete from normal breast parenchyma

• Can encompass small or large areas of the breast

• Interspersed fat and normal fibroglandular tissue

• NME characteristics: distribution, internal enhancement, kinetics

Non-mass enhancement may be 2/2 normal fibrocystic changes vs DCIS

SUSPICIOUS NON-MASS ENHANCEMENT!

• Distribution: linear, segmental

• Internal enhancement patterns: clumped, clustered ring, heterogeneous

DDX for NME: DCIS, ILC, LCIS, Fibrocystic change, Inflammation, Focal adenosis

LSDMRF

• Focal

  • Confined to a small area; ~25% of a quadrant

• Linear

  • Straight or curved line of enhancement that can branch; suggestive of a ductal process 

  • DDX: DCIS, Papilloma, Fibrocystic change

  • 46% rate of malignancy

• Segmental 

  • Triangular / cone / wedge shaped enhancement with the apex at the nipple

  • Suggests enhancement in a lobe or segment of the breast

• Regional 

  • Large area not conforming to ductal pattern; encompasses more than 1 ductal system

  • Can range from normal variant to lobular neoplasia to invasive carcinoma

  • Fibroadenomatoid changes can uncommonly present this way.

• Multiple regions

  • Geographic patchy enhancement

  • Greater than or equal to 2 regional areas

• Diffuse

  • Randomly distributed enhancement throughout the breast

• Normal variant inflow phenomenon - presence of NME in peripheral location (medial or lateral) related to contrast inflow through feeding vessels.

  • This pattern is more typical during the luteal phase of menstrual cycle (days 14-28) which is why MR should be performed b/n days 6 and 12 of menstrual cycle

• Homogeneous - confluent, uniform

• Heterogeneous - nonuniform, random

  • Separated by areas of parenchyma and fat

• Clumped - cobblestone or grape-like enhancement of varying shapes and sizes

  • Suspicious with PPV of 30-40%

• Clustered ring - thin rings of enhancement clustered together

  • Represents enhancement of periductal stroma

  • High association with malignancy (PPV of 87%). Not associated w/ hormone-related enhancement or normal variant.

    • Malig causes: DCIS (MC) or IDC or ILC (less common). 

    • Benign:  Fibrocystic changes and ruptured/inflamed cysts  

• Abnormal enhancement = enhancement of higher SI compared to BPE on first post con image

  • More critical in determining the possibility of malignancy in cases w/ more benign-appearing morphology

• Rate of contrast uptake and washout depend on: perfusion, capillary permeability, blood volume, contrast media distribution volume, local anatomy and physiology

• Malignant lesions

  • Tumors often have highly permeable vasculature and rapid BF, tend to enhance more than surrounding tissues. Tend to have rapid initial enhancement and delayed washout.

• Benign lesions tend to have slow initial enhancement and progressively increasing enhancement over time.

• How to use software

  • Review color images

  • Review kinetics of enhancing lesions:

    • Kinetic heterogeneity of lesions is common, normal LNs show washout kinetics

    • Make sure ROI is over the most avidly enhancing region and report the worst appearing kinetic curve

• Morphology is usually more important than kinetics. Thus, base management on the morphology and most suspicious kinetic pattern (NOT on the dominant kinetic pattern)

  • Thus if there is a speck of red, the lesion has washout kinetics

• There is significant overlap in kinetics of benign and malignant lesions. Thus morphology trumps kinetics.

• Cancer can display any type of kinetic curve. If it looks suspicious, do not allow kinetics to sway you, bx it.

• If a lesion is below the threshold for kinetics, it is most likely benign (93-100%)

• 2 sets of descriptors describe kinetic enhancement on breast MR imaging: initial rise and delayed phase generated from multiple time points following injection of contrast

(1) Initial phase (first 2 min or until peak; 1st postcon compared to noncon as a % signal increase)

• • Slow (<50% increase in SI; least suspicious)

  • Medium (50-100% increase in SI)

  • Fast (>100% increase in SI; most suspicious)

(2) Delayed phase (after 2 min or after peak)

• • Type 1 / Persistent (>10% increase in SI over time): continuous increase in SI over time. Blue color.

    • 6-17% chance of malignancy; 9% of malignant lesions have this pattern

  • Type 2 / Plateau (no change in signal / flat curve): flat curve after initial increase. Green or Yellow color.

    • 30-50% chance of malignancy; concerning for malignancy

  • Type 3 / Washout (>10% decrease in SI over time): initial increase then decrease. Red color.

    • 57-87% chance of malignancy; strongly suggestive of CA

LYMPH NODES

ASSOCIATED FEATURES

• Nonenhancing findings can include:

  • Cysts: T1 hypo T2 hyper, nonenhancing on T1 post con, subtraction and MIP, thus no kinetic curve assessment.

    • Some institutions dont event comment on cysts

  • Lipoma

  • Postop fluid collection (Seroma/hematoma)

  • Hamartoma

  • Signal void from clips/foreign bodies

INTRAMAMMARY LNs

SKIN LESIONS

• Skin / nipple thickening or enhancement

  • Cannot bx via MR

  • If suspicious enough, send to surgeon for skin punch bx

IMPLANTS

EXTRAMAMMARY FINDINGS

• T2 is most helpful

• Common findings:

  • Hiatal hernia

  • Liver lesions (get liver MR if there is enhancement)

  • Pleural effusion

• Less common findings:

  • Pulmonary nodule

  • Cardiac mass

  • Bronchogenic cyst

  • bloot clot / PE

  • Sternal bone lesions

    • Most bone lesions are T1 hypo T2 hyper

      • Exclude fat containing hemangioams, otherwise consider recommending bone scan vs PET scan

      • Multiplicity >1 lesion enhancing; noncircumscribed, extension beyond bone cortex, heterogeneous enhancement.

      • Always look at localizer imaging to evaluate the spine

• Breast MRI is technically demanding are requires excellent fat sat, high spatial resolution, and rapid performance of post contrast sequences

• Patient and technical factors can result in artifacts which degrade quality and confound interpretation

• Types of artifacts: motion, wraparound, zebra, RF interference, incomplete fat saturation, incorrect coil usage.

INVASIVE MALIGNANCY

• MRI is useful to determine EOD, cancer in CL breast, response to neo and occult breast CA in a patient w/ axillary mets w/ negative mammogram/us

• IDC is MC 

• Classic appearance: irregular enhancing mass w/ or w/o rim enhancement and washout kinetic curve

• Probability of malignancy approaches 100%

DCIS

• Although MRI is extremely sensitive to detect malignancy, it is slightly diminished for DCIS (77-96%)

• Classic appearance:

  • Non-mass enhancement, clumped enhancement in a linear or segmental distribution

  • Variable kinetic curves reported

  • Unreliable discriminator - persistent kinetic curve should not dissuade bx of a morphologically suspicious finding.

• MRI may depict the true extent of noncalcified DCIS

• Consider MRI in patient w newly diagnosed DCIS if young, dense breasts mammographically, extensive calcs w/ possible underlying invasive component.

• Correlate w/ mammogram

  • If calcs on mammo and MRI in same location, consider stereo bx first

  • If no mammographic correlate, 2nd look US (lower yield for DCIS than a mass)

  • If no US correlate, proceed w/ MRI bx

FIBROADENOMA

• Often multiple seen

• If isolated to one mass, consider more suspicious etiology

• In high risk patients, especially those BRCA+, malignancy can masquerade as benign findings

• Classic appearance

  • Oval, circumscribed, +/- gentle lobulation

  • Homogeneously enhancing mass +/- nonenhancing internal septations

  • Nonenhancing internal sepatations -> high NPV

  • May have increased T2 signal, variable

• Degenerating FA may not enhance

• Kinetic analysis is variable but classically demonstrates persistent enhancement

CASES