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Armed Forces Institute of Pathology Breast Disease www.radpath.org
Armed Forces Institute of Pathology Interpretation of Breast MRI Leonard M. Glassman MD FACR American College of Radiology Breast Imaging Scientist Armed Forces Institute of Pathology Washington DC Washington Radiology Associates, PC Washington DC glassmanl@afip.osd.mil
Why MRI? Mammography is imperfect Ultrasound is limited New technologies have limited data Positron emission mammography Breast scintigraphy
Indications Problem Solving Screening High risk groups General population?? Cost Availability
Breast Implants
Breast Implants
Problem Solving Pretreatment staging Residual disease Recurrence after breast conservation Problem patient/mammogram/sonogram Metastatic disease with unknown primary Usually for enlarged axillary or supraclavicular nodes Response to chemotherapy
Pretreatment Staging MRI changes treatment in 15-30% Multifocal/multicentric disease Lumpectomy to mastectomy in 15% Larger area for lumpectomy than indicated by mammography or sonography Chest wall involvement 2-3% have cancer in the opposite breast
Preoperative Multiple Sites
Preoperative Larger Lumpectomy
Preoperative Both Breasts
Residual Disease Postoperative residual disease Postlumpectomy preradiation Used if margins positive or close
Residual Disease
Recurrence After Breast 10% recurrence at 10 years MRI usually positive for at least 2 years after completion of treatment Abnormal findings after 2 years are suspicious Conservation
Problem Patient/Mammogram/Sonogram Symptomatic patient with negative mammogram/sonogram Unknown primary MRI positive in 50% Asymmetries Global or focal Abnormality in 1 view Multiple rounded solid masses
Problem Mammogram/Sonogram Pathologic nipple discharge MR ductogram Calcifications 85% or less negative predictive value Not good enough
Response to Chemotherapy Effectiveness of treatment (metabolic response to treatment) Change in size Routine contrast (change in kinetic curve) Diffusion weighted (free interstitial water diffusion rate) MR spectroscopy (choline peak change) Can predict response after days or weeks of treatment, not months
Response to Chemotherapy
Screening High risk women Average risk women??
High Risk Screening American Cancer Society Guidelines MRI and annual mammograms beginning at age 30 20% or more lifetime risk (double the general risk) BRCA 1 or 2 Parent, sibling or child with BRCA 1 or 2 Radiation treatment to chest between ages 10 and 30 Begin 10 years after treatment Significant positive family history
Significant Positive Family History One first degree relative with breast cancer before age 50 doubles risk (to 20%) Mother, sister, daughter Father, brother, son
High Risk Syndromes Li-Fraumeni Multiple cancers Cowden (Multiple Hamartoma Syndrome) Multiple cancers (breast and thyroid) Bannayan-Riley-Ruvalcaba Similar to Cowden Syndrome
Minimum Technical Specifications 1.5 T or greater Bilateral breast coil Resolution 1mm or less in plane Contrast enhancement Active fat suppression or subtraction on contrast sequences Biopsy availability
CAD Motion registration Multiplanar reconstruction Subtraction Automated kinetics Curves Peak enhancement Measurement package Kinetics only
CAD
Temporal vs. Spatial Resolution Initially temporal very important Now temporal less important Good spatial resolution more important Temporal resolution can be sacrificed for better spatial resolution
Type 1 Continued enhancement in delayed part of slope 6% malignant
Type 3 Rapid or medium initial phase Washout delayed phase 29-77% malignant
Type 2 Plateau in delayed part of slope 10% variance allowed from horizontal
Sequences
T1 Pre-contrast Not fat suppressed Central high signal Lymph node Fat necrosis Fresh and chronic Hamartoma
T2 Fat Suppressed High signal Cysts Colloid carcinoma Myxoid fibroadenoma Lymph node Fat necrosis Fresh and chronic Cysts
T2 Fat Suppressed High Signal Fibroadenoma Colloid carcinoma
T2 Fat Suppressed Moderate signal Invasive lobular carcinoma DCIS Fibrocystic change Low signal Invasive ductal carcinoma Sclerotic fibroadenoma Scar
T1-weighted Dynamic Contrast Enhanced 3D T1-weighted fat suppressed spoiled gradient-echo sequence typically Multiple runs over 5-8 minutes Each run <2 minutes for kinetics Gadolinium 0.1 mmol/kg bolus
Subtraction/Fat Suppression Must use active fat suppression or subtraction Patient motion limits usefulness of subtraction CAD software can help with motion Both is best
Sensitivity and Specificity Sensitivity 83-100% for invasive disease Specificity 29-100% for invasive disease
False negatives Poor enhancement pattern 16% DCIS and 3% invasive carcinoma Invasive lobular carcinoma Metastatic breast carcinoma Low grade DCIS Well differentiated invasive breast cancer Colloid carcinoma MRI dense breast High background enhancement Colloid carcinoma
Normal Examination Background enhancement Usually progressive over time Diffuse Hormonal enhancement Image between day 5 and 12
Hormonal Effects Luteal phase day 22 (Subtraction) Follicular phase phase day 10 (Subtraction)
MRI Dense Breast
Focus and Foci Enhancements < 5mm Too small to characterize Stable on follow-up usually Chance of malignancy extremely low
Benign Lesions Fibroadenoma Cysts Lymph nodes Fat necrosis Hamartoma Cysts (Post gad)
Cysts
Is MRI Definitive for Benign Lesions? Cyst Fibroadenoma Benign spatial characteristics Nonenhancing septations Type 1 curve Fatty lesions Hamartoma Lipoma Fat necrosis Lymph node Benign spatial characteristics Fatty hilum Benign lesions often hyperintense on T2
Fibroadenoma Benign spatial characteristics Nonenhancing septations Type 1 curve
Nonenhancing septations Fibroadenoma
Fatty Lesions Hamartoma Hamartoma
Mass 3D lesion Evaluate shape, margins and internal enhancement
Mass Shape Round Oval Lobulated Irregular 32% cancer Irregular (Angiosarcoma)
Mass Shape Oval (Juvenile fibroadenoma) Lobulated (Fibroadenoma)
Mass Margins Smooth Spiculated 80% cancer Irregular Smooth (Epidermal inclusion cyst)
Spiculated (Invasive ductal carcinoma) Mass Margins
Mass Margins Irregular (Adenoid cystic carcinoma)
Mass Internal Enhancement Pattern Homogeneous Heterogeneous Rim Cancer, fat necrosis, cyst with inflammation 40% cancer Dark internal septations Enhancing septations Central enhanced nidus or septations Homogeneous (Invasive ductal carcinoma)
Mass Internal Enhancement Pattern Heterogeneous (Invasive lobular carcinoma) Rim enhancement (Invasive ductal carcinoma)
Mass Internal Enhancement Pattern Dark septations (Fibroadenoma) Enhancing septations (Invasive ductal carcinoma)
Change Over Time
Non-mass Enhancement Enhancement without 3D characteristics Distribution Internal enhancement pattern Symmetry or asymmetry
Distribution Non-mass Focal < 25% of a quadrant Ductal 60% cancer Linear Not ductal orientation 31% cancer Segmental Multiple ducts 78% cancer Regional Not ductal or segmental 21% cancer Diffuse Focal (DCIS)
Distribution Non-mass Ductal (DCIS) Linear (Stromal fibrosis)
Distribution Non-mass Segmental (DCIS) Regional (DCIS)
Internal Enhancement Pattern Non-mass Homogeneous Heterogeneous Punctate Foci 25% cancer Clumped 60% cancer Reticular Homogeneous (DCIS)
Internal Enhancement Pattern Non-mass Heterogeneous (Invasive ductal carcinoma)
Internal Enhancement Pattern Non-mass Clumped (DCIS) Clumped (DCIS)
Associated Findings Skin or nipple involvement Signal void Muscle or chest wall invasion Dilated ducts Adenopathy
Associated Findings Chest wall invasion Adenopathy
DCIS Curves not useful Many cases of DCIS show no washout Usually cases with slow initial enhancement Non-mass enhancement Clumped, ductal, linear, segmental
DCIS
DCIS
Sarcoma Angiosarcoma Sarcoma with osseous differentiation
Conclusion MRI is a powerful tool in cancer diagnosis Can find cancer not seen on other imaging Problem solving High risk screening Can monitor chemotherapy better than other imaging
Conclusion Changes treatment plan in 15 30% of cases Larger lumpectomy or prelumpectomy chemotherapy Mastectomy But rate of change to mastectomy is greater than recurrence rate if MRI is not done