Download Breast Imaging Reporting and Data System (BI

Breast Imaging Reporting and
Data System (BI-RADS) for MRI
Wendy DeMartini, M.D.
Section Chief, Breast Imaging
Department of Radiology
University of Wisconsin School of Medicine
and Public Health
Interpretation Using BI-RADS
• American College of Radiology (ACR)
• Standardized language and data system
for breast imaging
• Many benefits
– Clear communication to patients and
providers
– Definitions for outcomes and audits
– Benchmarks and desirable goals
Interpretation Using BI-RADS
• 1992 Atlas
– 1st Edition
• 2003 Atlas
– Addition of US and MRI
• 2013 Atlas
– 5th Edition
– Update of all modalities
– Digital e-book version
BI-RADS Breast MRI Sections
• Breast MRI Lexicon
– Breast Tissue
– Findings
• Reporting System
– Assessments and Recommendations
categories
BI-RADS MRI Lexicon
Figure: ACR BI-RADS 5th Ed.
Breast Tissue -- Amount
of Fibroglandular Tissue (FGT)
• Assessed on T1-weighted imaging
• Amount of fibroglandular tissue
a.
b.
c.
d.
Almost entirely fat
Scattered fibrolandular tissue
Heterogeneous fibroglandular tissue
Extreme fibroglandular tissue
Heterogeneous
Breast Tissue -- Background
Parenchymal Enhancement (BPE)
• On initial post-contrast and/or related series
• Level of FGT with normal enhancement
(subjective, volume and intensity)
a.
b.
c.
d.
Minimal
Mild
Moderate
Marked
• Symmetric or asymmetric
Minimal, Symmetric
Moderate, Asymmetric
Mild, Symmetric
Marked, Symmetric
Images: University of Washington
BPE Significance
• Common, physiologic
• Varies between and within patients
– Menstrual cycle, hormone and anti-hormone
therapy
• A spectrum of patterns
• Concern that higher levels limit may
diagnostic performance
– Several studies show no significant impact
Findings
• Focus
• Mass
• Non-mass
enhancement (NME)
• Kinetic curve
assessment
• Associated features
• Non-enhancing
findings
• Fat containing lesions
• Intramammary lymph
node
• Skin Lesion
• Implants
Findings
• Focus
• Mass
• Non-mass
enhancement (NME)
• Kinetic curve
assessment
• Associated features
• Non-enhancing
findings
• Fat containing lesions
• Intramammary lymph
node
• Skin Lesion
• Implants
Focus
•
•
•
•
Unique punctate enhancing “dot”
Usually < 5 mm
Otherwise too small to characterize
Dismiss if/when
– Multiple separated by normal tissue >> BPE
– Uniform and T2 hyperintense >> benign
• Compared to initial MRI use, fewer foci
– Improved technique, more experience
Foci
Images: University of Washington
Mass
• A three dimensional space-occupying
lesion
• Mass characteristics
– Shape
– Margins
– Internal enhancement
– Kinetics
Mass Shapes
• Round: spherical
• Oval: up to three gentle lobulations
• Irregular: uneven, cannot be
characterized one of the other shapes
Mass Margins
• As for mammography and US, important
predictors of likelihood of malignancy
• Circumscribed
• Not circumscribed
– Irregular
– Spiculated
Mass Internal Enhancement
•
•
•
•
Homogeneous: uniform, confluent
Heterogeneous: non-uniform, variable
Rim: peripheral
Dark internal septations
– Suggestive of fibroadenoma
– As an isolated feature, NPV insufficient to
exclude malignancy
– Useful if supported by other features
Mass Examples
Prior Left
Lumpectomy
Mass (Oval, Circumscribed, Homogeneous)
(Fibroadenoma)
Images: University of Washington
Mass (Irregular, Spiculated, Homogeneous)
(IDC)
Images: University of Washington
Mass (Irregular, Spiculated, Rim Enhancement) (IDC)
Images: University of Washington
Non-Mass Enhancement (NME)
•
•
•
•
An area that is not a focus or mass
Discrete from normal breast parenchyma
May extend over small or large regions
Spots of normal glandular tissue or fat
interspersed
NME Characteristics
• Distribution
• Internal enhancement
• Kinetics
NME Distribution
• Linear: straight or curved, may branch
• Segmental: triangle/cone with apex pointing
toward nipple
• Focal area: small confined area, generally <
25% of a quadrant
• Regional: in a large volume not conforming to
ductal distribution, geographic
• Multiple regions: >= 2 regional areas
• Diffuse: throughout breast
NME Internal Enhancement
Patterns
• Homogeneous: uniform, confluent
• Heterogeneous: non-uniform, separated
by areas of parenchyma or fat
• Clumped: cobblestone- or grape-like
– Implies a suspicious finding
• Clustered ring*: thin rings around ducts,
especially on high SR imaging
– Implies a suspicious finding
NME Examples
NME (Linear, Homogenous) (DCIS)
Images: University of Washington
NME (Linear, Heterogeneous)
(Sclerosing Adenosis)
MRI BIOPSY
Images: University of Washington
NME (Segmental, Heterogeneous) (IDC)
Images: University of Washington
NME: Clustered Ring
Image: Tozaki M. AJR Am J Roentgenol. 2006 Aug;187(2):313-21.
PPVs of BI-RADS Morphology Features
ACRIN 6667: 278 BI-RADS 0, 3, 4 or 5 lesions
Morphology
PPV
Focus
0.019
NME
Ductal
Clumped
Mass
Irregular
Spiculated
0.127
0.500
0.304
0.140
0.306
0.333
• Likelihood of
malignancy
depends on
combinations of
features
• For lesion types
– Foci < masses
– Masses = NME
Mahoney, et al. The Positive Predictive Value of MRI BI-RADS. Radiology 2012.
Lexicon: Findings
• Focus
• Mass
• Non-mass
enhancement (NME)
• Kinetic curve
assessment
• Associated features
• Non-enhancing
findings
• Fat containing lesions
• Intramammary lymph
node
• Skin Lesion
• Implants
Kinetic Curve Assessment
• Enhancement characteristics over time
• Signal intensity curve
– Initial phase: within first 2 minutes or until
peak
– Delayed phase: after first 2 minutes or after
peak
• Report worst looking kinetic curve
• Semi-quantitative
– Does not consider arterial input function
>100%
50-100%
>10%
Increase
+/- 10%
<50%
>10%
Decrease
PreContrast
Initial PostContrast
Delayed PostContrast
CAD Kinetics Assessment
Practical Kinetics
• Malignancies “classically” have rapid initial
and delayed washout kinetics
• Significant overlap in kinetics of benign
and malignant lesions
• Very dependent on technique, CAD
system
• Morphology is more predictive of
malignancy
Slow Initial Enhancement (<50%)
= Benign Ductal Hyperplasia
IMMEDIATE POST
WITH COLOR MAP
100% Persistent Delayed Enhancement
= Invasive Ductal Carcinoma
Initial phase
Medium
Rapid
0%
100%
Delayed phase
Persistent
100%
Plateau
0%
Washout
0%
IMMEDIATE POST
WITH COLOR MAP
Lexicon: Findings
• Focus
• Mass
• Non-mass
enhancement (NME)
• Kinetic curve
assessment
• Associated features
• Non-enhancing
findings
• Fat containing lesions
• Intramammary lymph
node
• Skin Lesion
• Implants
Associated Features
• Nipple retraction, invasion
• Skin retraction, thickening, invasion
• Lymphadenopathy
– Describe axillary levels involved
AXILLA
IM CHAIN
LYMPHADENOPATHY
Associated Findings
• Pectoralis muscle
invasion
• Chest wall invasion
– Not pectoralis, extending into ribs or
intercostal muscles
Lexicon: Findings
• Focus
• Mass
• Non-mass
enhancement (NME)
• Kinetic curve
assessment
• Associated features
• Non-enhancing
findings
• Fat containing lesions
• Intramammary lymph
node
• Skin Lesion
• Implants
Non-Enhancing Findings
• Pre-contrast high
duct signal
– Hyperintense T1
signal in ducts
– Benign,
protein/blood
• Cysts
Non-Enhancing Findings
• Non-enhancing mass
• Post-operative collection
• Post-therapy skin and trabecular
thickening
• Signal void (clips)
Lexicon: Findings
• Focus
• Mass
• Non-mass
enhancement (NME)
• Kinetic curve
assessment
• Associated features
• Non-enhancing
findings
• Fat containing lesions
• Intramammary lymph
node
• Skin Lesion
• Implants
Fat-Containing Lesions
• Lymph node
– Normal
– Abnormal
• Fat necrosis
• Hamartoma
• Post-operative seroma/hematoma with fat
(and fluid)
Images: ACR BI-RADS 5th Ed.
BI-RADS Reporting System -Assessment and (Concordant)
Management Recommendations
Figure: ACR BI-RADS 5th Ed.
Breast MRI-Specific
Considerations
• A separate BI-RADS assessment should
be given for each breast (or lesion)
• Single BI-RADS assessment acceptable if
both breasts are 1 and/or 2
• Overall examination coded according to
“most worrisome” actionable BI-RADS
5 > 4 > 0 > 6 > 3 > 2/1
Breast MRI-Specific
Considerations
• With history and comparisons exams,
assessment and management (biopsy/no
biopsy) based directly on MRI features
• Employ assessments appropriately
• Suspicious findings are BI-RADS
Category 4 or 5 (do not use Category 0
when targeted ultrasound recommended
to guide biopsy)
Category 0: Incomplete--Need
Additional Imaging Evaluation
• Use discouraged, should be rare
• Suggestive but not definitive of benign
lesion, further characterization
– Possible lymph node, fat necrosis
– Next steps (follow-up, biopsy) if additional
imaging does not establish benignity
• Technically unsatisfactory exam
• Sometimes to obtain prior studies
Category 1: Negative
• No abnormality found
• Recommend routine screening
Category 2: Benign Finding
• Benign finding(s)
– Fibroadenoma, cysts
– Prior biopsy or surgery
• Recommend routine screening
Category 3: Probably Benign Finding
• Very high likelihood that benign
– <=2% probability of malignancy
• Not for BPE
• Finding should be unique/distinct
• Use should be infrequent
– “Desirable goal…less than 10%...over
time…should decrease to…1-2%”
• Intuitive, limited data for MRI lesion types
• Follow-up typically at 6, 12 and 24 months
Category 3: Probably Benign
Finding
• Practical considerations also limit use
– Not appropriate on MRI for extent of disease,
goal is guiding near-term management
decisions
– Reimbursement for short-term follow-up MRI
is variable
– Incomplete patient compliance with follow-up
Category 4: Suspicious Abnormality
• MRI not currently subdivided into 4A-C
– Used in some practices
• Recommend tissue diagnosis
– Specify imaging modality and contingencies
• Mammo (rare)
• US (targeted US and bx, if negative MRI bx)
• MRI
• Possible wording: In the absence of clinical
contraindication, image-guided tissue sampling
Category 4 Subdivisions (4A-C)
• Use suggested for mammography and
ultrasound, not currently for MRI
• Meaningful audit, rad-path correlation and
patient/provider expectations
• Used routinely in our practice
Category 4 Subdivisions (4A-C)
• Malignancy rates in BI-RADS ranges
• Supports use of subdivisions for MRI
Strigel RM, et al. Presented at the American College of Radiology/Society of
Breast Imaging Symposium, Bonnet Creek, FL. April, 2015.
Category 5:
Highly Suggestive of Malignancy
• No single feature >95% PPV, combinations
• “Any nonmalignant percutaneous tissue
diagnosis is discordant”
• Recommend tissue diagnosis
– Specify imaging modality and contingencies
• Mammo (rare)
• US (targeted US and bx, if negative MRI bx)
• MRI
• Possible wording: In the absence of clinical
contraindication, image-guided tissue sampling
Category 6:
Known Biopsy-Proven Malignancy
• An MRI finding that corresponds to the
biopsy proven breast cancer
• Prior to definitive surgical excision
• Index lesion on MRI
– Extent of disease prior to treatment
– Response to treatment during neoadjuvant
chemotherapy
BI-RADS Assessment in Known
Biopsy-Proven Malignancy
• The biopsy-proven cancer is BI-RADS
Category 6
• Additional suspicion lesions that have not
been sampled are BI-RADS Category 4 or
5
• The examination is coded according to the
highest order actionable BI-RADS
5 > 4 > 0 > 6 > 3 > 2/1
Screening Audit Benchmarks
Abnormal interpretation rate (0, 3, 4, 5)
8-17%
Assumptions CDR 3/100, PPV3 20-50%, BI-RADS 3 2%
D’Orsi CJ, Sickles EA, Mendelson EB, Morris EA et al. ACR BI-RADS® Atlas, Breast Imaging
Reporting and Data System. Reston, VA, American College of Radiology; 2013.
Diagnostic Audit Benchmarks
• Dependent on indication and patient mix
• New cancer extent of disease
– Cancer more frequent than at screening
– Cancer detection rate 100-150/1000 (10-15%)
– Abnormal interpretation rate expected to be
higher than screening
Figure: ACR BI-RADS 5th Ed.
Case
•
•
•
•
58 y.o.
High risk screening
BRCA2 gene mutation carrier
Comparisons
– Mammo: negative
– MRI: negative
MIP
Level of BPE
Significant Unique Finding(s)?
Other Sequences (DCE, T2, NFS)
Level of BPE
Significant Unique Findings(s)?
Features >> Morphology
CAD Color Map
Kinetics
Slow/Med, Plateau/Persist
Less Suspicious
Fast/Washout
(More) Suspicious
Comparison
MIP
BPE?
Significant unique findings?
Images: University of Washington
Comparison
Right 5 o’clock
Initial post-contrast
T2
Subtraction
Images: University of Washington
Morphology and Kinetics
Initial post-contrast
NME, segmental, heterogeneous
Initial phase fast, delayed phase washout
Assessments and
Recommendations
• Right breast
– Non-mass enhancement at 5 o’clock. BIRADS 4B. Recommend image-guided biopsy
(MRI).
• Left breast
– Negative. BI-RADS 1. Recommend routine
screening.
• Overall assessment
– BI-RADS 4B.
Case
•
•
•
•
•
47 y.o.
MRI for extent of disease
Newly diagnosed right breast DCIS
8 o’clock, 34 mm mammographically
Comparisons
– Mammo: right calcifications
MIP
BPE?
Significant unique findings?
Right breast 8 o’clock
Known
cancer
Initial post-contrast
T2
Subtraction
NME (focal, clumped)
Left breast
Initial post-contrast
T2
Subtraction
Morphology and Kinetics
Initial post-contrast
Mass, irregular, spiculated, heterogeneous
Initial phase fast, delayed phase washout
Assessments and
Recommendations
• Right breast
– Biopsy-proven malignancy at 8 o’clock. BIRADS 6. Recommend clinical follow-up.
• Left breast
– Mass at 3 o’clock, suspicious for malignancy.
BI-RADS 4C. Recommend image-guided
biopsy (MRI).
• Overall assessment
– BI-RADS 4C.
Summary
• As for mammography and ultrasound, use
of BI-RADS for MRI facilitates clear and
appropriate
– Characterization of findings
– Assessment and management
Thank you!