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Breast ImagingMedical School Lecture
November 18, 2015Susan Peddle, MDAssistant ProfessorUniversity of Ottawa
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Overall Objectives
• Review the background and evidence supporting the use of screening mammography, ultrasound (US) and magnetic resonance imaging (MRI)
• Describe Canadian population‐based screening programs, their performance indicators and their costs
• Provide an overview of mammographic abnormalities and their work‐up
• Screening versus Diagnostic mammography
• BI-RADS
• Review of mammographic abnormalities that warrant further work-up
• Diagnostic work-up
• Features of benign versus malignant lesions on ultrasound
• Breast Intervention
• Role of MRI in breast imaging
• Current recommendations for breast screening
Objectives
• Screening versus Diagnostic mammography
Objective 1
• Screening MG: to find cancers smaller than those detected at BSE or CBE
Sensitivity of BSE: Unknown
Sensitivity of CBE: Unknown
Sensitivity of screening MG: 75-90%
• Diagnostic MG: to further evaluate a screen detected abnormality, symptom or clinical finding
Pain
Palpable lump
Nipple Discharge
Others (skin changes, nipple inversion, shrinking breast, enlarging breast)
Screening MG versus Diagnostic MG
pectoralis muscle
inframammary fold
lymph node
fat
glandular tissue
vessel
skin
Cooper’s ligaments
subareolar lactiferous
ducts
Mammographic Mammographic AnatomyAnatomy
Typical Mammography Unit
Routine Mammographic Views
CC
MLO
MLO CC
Upperquadrant
Lowerquadrant
Outerquadrant
Innerquadrant
12:00
9:00 3:00
6:00
MedLat
O’clock Position used for Localization
6:00
3:009:00
12:00
Right Breast Left Breast
Med Lat
Technical Limitations
• Breast Density
• Patient anxiety, discomfort, physical limitations
• Post-therapeutic changes
Breast Density
fatty replaced0-25%
scattered25-50%
heterogeneous50-75%
extremely dense
75-100%
• BI-RADS
Objective 2
BI-RADS
• Breast Imaging Reporting and Data System
• Helps achieve uniformity in breast imaging reports which improves their clinical utility by communicating findings in a standardized way
• Help determine clear management
• 0: Needs further evaluation
• 1: Normal
• 2: Benign finding
• 3: Probably benign
• 4: Suspicious abnormality
• 5: Probable cancer
• 6: Biopsy proven cancer
BI-RADS
• 0: Needs further evaluation - additional mammographic views, +/- US, +/- MRI
• 1: Normal - Return to screening
• 2: Benign finding - Return to screening
• 3: Probably benign - > 98% likelihood of being benign. Short interval follow-up recommended in 6 months.
• 4: Suspicious abnormality - Biopsy needed
• 4A - 10-50% likelihood of being malignant
• 4B - 50-95% likelihood of being malignant
• 5: Probable cancer - Biopsy and surgical consultation needed (> 95% likelihood of being malignant)
• 6: Biopsy proven cancer
• Review of mammographic abnormalities that warrant further work-up
Objective 3
4 Main Mammographic Abnormalities
• Microcalcifications
• Architectural distortion
• Mass
• Asymmetries
Microcalcifications
Microcalcifications• Microcalcifications can be an
indicator of cancer, although they are often benign
• Detected mammographically
• Characterized by morphology (appearance), distribution, and change over time
• Analysis helps radiologist determine the likelihood of underlying benign versus malignant pathology
image
Terminal Ductal Lobular Unit (TDLU)
• Basic functional unit in the breast
• Consists of 10-100 acini that drain the terminal duct
• Terminal ducts drain to larger and larger ducts, and eventually to the nipple
TDLU - site of origin of most cancers
Lobular Calcifications- form in acini -
Intraductal Calcifications- form in ducts -
Almost always benignSuspicious for malignancy
Due to calcified cellular
debris or secretions
Skin
Vascular
Coarse or “Popcorn”
Rim or “Eggshell”
Benign Calcifications
Fine Pleomorphic
“Variable in size, density and shape”
Suspicious Microcalcifications
“Thin, linear or curvilinear irregular”
Fine linear or branching
Suspicious Microcalcifications
Architectural Distortion
Architectural Distortion
• Normal architecture is distorted with no definite visible mass
• Look for abnormal straight lines or spiculations radiating from a point
• Differential diagnosis:
• Carcinoma vs scar tissue
Right - recurrence with IDC Left - IDC
Right - recurrence with IDC Left - IDC
Mass
Mass• A space occupying
3D lesion seen in two different projections
• 3 important descriptive terms:
• Shape
• Margin
• Density
•Benign features
• Round or oval
• Circumscribed
• Low density
•Suspicious features
• Irregular
• Microlobulated, indistinct, spiculated
• High density
Typically Benign
Typically Malignant
Asymmetries
Asymmetries• Unilateral deposits of
fibroglandular tissue with NO mirror-image correlate in the opposite breast
• A discrete mass is not seen on the initial MLO and CC views
• True pathology versus overlapping normal tissue?
Asymmetry
??
Rt MLO Lt MLO
Focal Asymmetry
Global Asymmetry
Objective 4
• Diagnostic work-up
“Work-up”
• Refers to additional testing required to determine the origin of an imaging or clinical abnormality
• Comprised of additional mammographic views, US, MRI and/or biopsy
Abnormal Mammogram
Additional mammographic views
? True abnormality
+/- Ultrasound
? Mass
+/- Biopsy
? Suspicious
• Straight lateral or 90 degree view
• Coned compression views
• Magnification views
• Pinched (Eklund) views
• Rolled view
• Extended CC view
• Cleavage view
• Tomosynthesis
Additional Mammographic Views
Magnification Views • Performed for better characterization of microcalcifications
• Focal spot = 1.6 times
• 2 views: CC and straight lateral (90 degree)
Magnification ViewLt MLO
Coned Compression Views
• Performed to differentiate normal overlapping parenchyma from a true abnormality
Coned Compression
Lesion does not persist on coned compression views in keeping with normal
fibroglandular tissue
Lesion persists on coned compression views in keeping with a true lesion
Coned Compression Views
Ultrasound confirms the presence of a mass suspicious for malignancy
Tomosynthesis
• - New technique created to produce a 3D picture of the breast using X-rays
• - Designed to reduce overlapping tissues in mammography
• - Results in high-resolution images at mammographic doses
Breast
Reconstructed planes
2D 3DTomosynthesis
Stationary breast
platform
X-ray tube swings during
tomo
QuickTime™ and a decompressor
are needed to see this picture.
Tomosynthesis
• Ultrasound features of benign versus malignant lesions
Objective 5
Ultrasound
Benign vs Malignant Features
Simple Cyst
• Always benign
• Features:
• Anechoic (black)
• No wall
• “Through transmission”
Ultrasound Features of Solid Masses
Classic maligna
nt
Classic benign
Benign Breast Lesions
• Well circumscribed - doesn’t invade
• Wider than tall - obeys normal tissue planes
• Thin echogenic pseudocapsule - compresses adjacent tissue
• Gentle macrolobulations
• Intensely echogenic - contains fat
• Angular margins
• Spiculations
• Microlobulations
• Taller than wide
• Posterior shadowing
• Ductal extension/Branch pattern
• Microcalcifications
Malignant Breast Lesions
Margins: Angulated
Margins: Microlobulated
Ductal extension
Shadowing
Can we make the diagnosis of cancer based on ultrasound
features only?
Case 1: 83 yo, palpable mass medial left breast
Case 2: 88 yo, palpable mass UOQ left breast
Case 1: 83 yo, palpable mass medial left breast
Case 2: 88 yo, palpable mass UOQ left breast
Cancer Fibroadenoma
Invasive ductal carcinoma Involuted calcified
fibroadenomas
Always start with a MG in women 35
years old and greater!
• Breast Intervention
Objective 6
• Tissue diagnosis mandatory for diagnosis of breast cancer
• In the US, 1 million breast biopsies are performed annually to diagnose 200,000 breast cancers
• Avoids unnecessary benign surgical excisions and allows surgeons to plan appropriate surgery in the setting of cancer
• Extremely beneficial for patients and for the health care system in general
Breast Intervention
• How do we perform breast biopsies?
• Ultrasound guided biopsy
– Solid and complex solid-cystic masses
• Stereotactic biopsy
– Suspicious or indeterminate microcalcifications seen on MG
– Persisting suspicious asymmetries on MG with no sonographic correlate
• MRI guided biopsy
– Lesions identified only on MRI with no mammographic or sonographic correlate
Breast Intervention
Ultrasound Guided Biopsy
FNA(uncommon
) CNB VAD
Core Needle Biopsy
Fine needle aspiration
Vacuum-assistedDevice
Core Biopsy
QuickTime™ and aPhoto - JPEG decompressor
are needed to see this picture.
Vacuum Assisted Biopsy
QuickTime™ and aPhoto - JPEG decompressor
are needed to see this picture.
Stereotactic Guided Biopsy
Technique
• Scout image taken to locate lesion in biopsy window
• “Stereo Pair” obtained after moving x-ray tube +15° and −15° relative to 0° position
• X, Y and Z (depth) coordinates calculated by computer
Specimen radiograph confirms microcalcifications in the
specimen
Final diagnosis: DCIS
Pre biopsyPre biopsy
Post biopsyPost biopsy
Persisting focal asymmetry
Deploy marker clip at the site of biopsy
Preoperative Image Guided Localizations
• Pre-operative localization is used to ensure complete excision of nonpalpable breast lesions
• Localization device is inserted pre-operatively using mammographic or ultrasound guidance
• Helps guide the surgeon in the OR, improving clear margin and breast conservation rates
Preoperative Image Guided Localizations
MG or Ultrasound Guidance
46 yo - Multifocal Disease UOQ
2 wires inserted to guide surgical
excisions
Radioactive Seed Localization
• Low-dose I125 titanium prostate seed is placed at the target using mammographic or ultrasound guidance
• Surgeon uses radioactivity probe to localize, dissect and remove breast lesion
Image courtesy of The Mayo Clinic
Post-procedure mammogram
confirms accurate seed
placement adjacent to clip
X-ray of lumpectomy specimen to
confirm excision
• Role of MRI in breast imaging
Objective 7
• MRI has a high sensitivity
• Main roles include:
– High risk screening:
– BRCA 1 and 2 mutation carriers
– > 25% lifetime risk of developing breast cancer
– Radiation to anterior chest wall for treatment of lymphoma
– Local staging of breast cancer
– Assess response to chemotherapy
– Problem solving
Role of MRI in Breast Imaging
43 yo – BRCA1 carrier
Baseline Screening MRI
Bilateral breast cancer not seen mammographically
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Left breast
Clinical: • Upper outer quadrant • Palpable abnormality
MG: • Pleomorphic microcalcifications (BI-RADS 5)
Stereotactic Biopsy:
Final diagnosis: DCIS high grade
CC MLO
Local Staging with MRI
MRI: • Non mass enhancement (arrow) • Additional retroareolar mass (circle) for which US guided biopsy was performed
Mastectomy and SLNB wereboth performed
Final pathology: Invasive ductal carcinoma and ductal carcinoma in situ (DCIS)
(Total extent 8.0 cm)
2 min C+
2 min C+
2 min MIP
January 2012 July 2012
Post 6 cycles of chemotherapy
Assess response to chemotherapy with MRI
• Current recommendations for breast screening
Objective 8
– Who should have mammograms?
– At what age should screening be initiated?
Current Recommendations for Screening
Benefits of Screening Mammography
• - Reduction in breast cancer mortality by 40%
• - Lower rate of mastectomy, radiation therapy and axillary lymph node dissection
• - Less expensive treatment and less time off work
Limitations of Screening
Mammography...”Harms”• False Negatives
• 10-20% of breast cancers are only detected at breast self-exam or physical exam
• False Positives
• Only 5-40% of lesions are detected at screening and recommended for biopsy
• Over-diagnosis
• 11% of cancers found never progress
• Asymptomatic women 40-49 years - Annual screening MG
• Asymptomatic women 50-74 years - Every 1-2 years
• Women over 74 years - Every 1-2 years, if in good health
CAR Guidelines – Screening Mammography
When to Start Screening?
• - CTFOPH recommends screening women 50-74 and having a discussion about screening with women 40-49
• • - OBSP screens women 50-74
• - Canadian Association of Radiology, American Cancer Society, National Comprehensive Cancer Network, American College Radiology, College Obstetricians and Gynecologists, recommend screening women 40-74 +
Should I Screen after age 74?
• - For all ages, the mortality benefit from mammographic screening begins to be seen 5-7 years after the onset of screening
• - Mammographic screening can be continued as long as there is reasonable expectation of a life expectancy of at least seven years
• - Average life expectancy for an 80 year-old woman is 8.6 years which means that the healthiest quartile can be expected to live considerably longer
What is the Chance of Developing Cancer between 40-50 years old?
• - 1 in 69 women will be diagnosed with invasive breast cancer in their 40s
• - Breast cancer is the leading cause of cancer death in women < 50 years
• - There is a very low incidence of breast cancer below age 30
• There is no abrupt change at age 50
Annual U.S. breast cancer incidence rates
per 100,000 women as a function of age for invasive + in-situ
cancers
Numbers of Breast Cancers by Age
SEER, 2010, http://seer.cancer.gov/csr/1975_2007/
77% > 50 years
18% 40 - 49 years
• 5% < 40 yrs
• 18% 40-49 yrs
• 23% 50-59 yrs• 26% 60-69 yrs• 28% 70-79 yrs
No Role for Screening with
Ultrasound
• Average risk women - Screen with mammography
• High risk patients - Screen with mammography and MRI
• Screening versus Diagnostic mammography
• BI-RADS
• Review of mammographic abnormalities that warrant further work-up
• Diagnostic work-up
• Features of benign versus malignant lesions on ultrasound
• Breast Intervention
• Role of MRI in breast imaging
• Current recommendations for breast screening
Objectives
Thank you
