Smriti Hari Additional Professor, Radiology

All India Institute of Medical Sciences

New Delhi, India

General Secretary

Breast Imaging Society (INDIA)

breastimagingsociety@gmail.com

Breast Diseases- Diagnosis

Imaging Modalities

Mammography is the primary modality

Ultrasound

MRI

PET

Recent Advances

Digital Mammography + Tomosynthesis +CAD

US Elastography

MR Spectroscopy + DWI

Breast Specific Gamma Imaging

Mammography –Technical challenges

Inherent contrast of breast tissue low

High contrast and spatial resolution needed to detect microcalcifications(100-200µ)

Motion unsharpness

Varying ant to post thickness of breast

Radiation dose

Mammography- Equipment

High contrast resolution

Low energy (20-30 kVp) Xrays: Mo

traget, Mo, Be filters

Short exposure time

Breast compression

High spatial resolution

Small focal spot(0.3mm)

High resolution film-screen combination/

Detector

Accreditation and Quality Control is

essential

Mammography- Projections

Craniocaudal

Projection Mediolateral

Projection

Criteria for well-positioned

CC and MLO Views

Posterior Nipple Line (PNL) on CC view should be within 1cm of its length on the MLO view

Mammography - Additional Projections

Extended CC

ML

Spot compression

Magnification

Smaller focal spot (0.1mm)

Distance between breast and film is increased

Axillary

Mammography - Indications

Screening mammography

Diagnostic mammography

Symptomatic women aged 30 years and over with

suspicion of breast cancer

Search of the occult primary

Post treatment surveillance

Mammography - Limitations

Not perfect; ~ 15% false negative

Sensitivity drops in women with dense

breasts ( 30-48%)

Fatty breast Dense breast

Advances in Mammography

Digital Mammography

Digital Breast Tomosynthesis

(DBT)

Computer Aided

Detectiion (CAD)

Dual Energy Mammography

Digital Mammography

Screen/Film replaced by detector

which produces an electronic signal

Powerful workstation

Up to 27 megapixels per image!

High resolution (5 megapixel), high

brightness monitors

Why Digital Breast Tomosynthesis

• Tissue superimposition : • Hides pathologies in 2D

• Mimics pathologies in 2D

• X-ray tube moves in an arc across the

breast

•

• A series of low dose images are

acquired from different angles

• Total dose approximately the same as

one 2D digital mammogram

• Projection images are reconstructed

into 1 mm slices

Reconstructed

Slices {

How Does Tomosynthesis Work?

Digital Breast Tomosynthesis

Conventional 2D Mammogram 1mm Breast Tomosynthesis slices

Computer Aided Detection (CAD)

Helps inexperienced radiologists

Inexpensive alternative to second radiologist (for double reading)

High false positives

Cancer detection rate increased by > 20%*

*AJR 2003;181:687-93

Mammography –Interpretation

Optimum lighting conditions

‘Back to back’ placement of films

Check for

Identification, Labelling

Radigraphic quality

Mammography Interpretation

American College of Radiology (ACR) Breast Imaging Reporting and Data System (BI-RADS)

Standardized method for describing the morphology of breast lesions and categorizing the findings in an unambiguous report

Parenchymal Density

Lexicon BI-RADS

Categories Report

Organisation

Category A (Entirely fatty)

Category B (Scattered fibroglandular tissue)

Category C (Heterogenously dense)

Category D (Extremely dense)

ACR BIRADS Categories of

Parenchymal density

Mammography-ACR BI-RADS

Lexicon

Mass

Calcification

Architectural distortion

Asymmetry

ACR BI-RADS - Mass Descriptors in

Mammography

Shape Margin

Density

Mass shape

P

robabili

ty o

f m

alig

nancy

Round

Oval

Irregular

Lobulated

Mass margins

Circumscribed Indistinct Obscured Spiculated Microlobulated

Mass Density: compared to the density of

equal volume of fibroglandular

parenchyma

Fat containing

High density (c/w

fibroglandular

parenchyma)

Equal dense

Low Density

ACR BI-RADS – Calcification

Descriptors in mammography

Morphology Number

Distribution

Calcification morphology

Typically Benign

Suspicious for

Malignancy

Typically Benign Morphology

Skin

Popcorn

Vascular

Rodlike

Round

Dystrophic

Suspicious morphology

Amorphous

Coarse hetrogenous

Fine pleomorphic

Fine linear or fine linear branching

Morphology- (Suspcious for malignancy)

Coarse heterogeneous Amorphous or indistinct

Fine pleomorphic

Fine linear/branching

Morphology- (Suspcious for malignancy)

ACR BI-RADS – Calcification

distribution Descriptors

Diffusely scattered

Linear

Segmental

grouped

Asymmetry

Asymmetry

Seen only on one view

Focal asymmetry

Seen on two views, but completely lacking borders

and conspicuity of a true mass.

Mass

Seen on two views, showing consistent

convex borders and space

occupying effect

Asymmetry needs further

evaluation if -

Corresponds with clinical abnormality

New development

Associated with calcification, architectural distortion

Special views to exclude true mass or architectural

distortion. Comparison to old mammograms if available, short

interval follow-up if not If special views show mass like character, or if the

area can be palpated - biopsy

Architectural distortion

Multiple thin, straight lines or spiculations radiating from an

area that does not have features of a mass or focal asymmetry

Postoperative scarring Carcinoma

BIRADS Classification (Mammography)

Category Description Likelihood of

malignancy

Examples Next step in evaluation

0 Incomplete Unknown Asymmetry, mass, calcifications on

screening mammography Special mammographic

views, US, MRI; obtain

previous examinations

1 Negative No mammographic

evidence of

malignancy

Normal mammography Routine screening

2 Benign finding No mammographic

evidence of

malignancy

Intramammary lymph node, oil cyst,

vascular calcifications, calcifying

fibroadenoma

Routine screening

3 Probably benign finding Less than 2 % Benign-appearing solid mass or

clustered calcifications Follow-up imaging

(mammography or US)

at six and 12 months

4 Suspicious abnormality 5 to 95 % Complex or solid mass, indeterminate

clustered calcifications Biopsy

5 Highly suggestive of

malignancy Greater than 95% Spiculated mass, pleomorphic

calcifications

Biopsy

6 Known malignancy 100 % Biopsy-proven Definitive treatment

Management of BIRADS 3 lesions

Short interval follow-up mammography every 6

months for 2 years (watchful waiting)

95%, no growth, bx is avoided

2-3 %, a benign process grows, and requires bx to establish its nature

1-2 % are cancer, growth is seen on follow-up, and bx initiates treatment. Although some time is lost in the process, the cancers found at follow-up are usually still small and curable.

45 Y lady with palpable lump in Left

breast UOQ

Mass

Architectural distortion

Asymmetry

Calcification

Shape

Round

Oval

Irregular

Margins

Circumscribed

Microlobulated

Obscured

Indistinct

Spiculated

Density

High

Low

Isodense

BI-RADS 1

BI-RADS 2

BI-RADS 3

BI-RADS 4

BI-RADS 5

BI-RADS 6

Fatty

Breast US: Indications

Symptomatic breast lump in women aged < 30 yrs/

during pregnancy or lactation/ in a male

To assess mammographic abnormality

To assess MRI detected lesions

Palpable lump with negative mammogram

Breast inflammation

Guidance of needle biopsy or localisation

ACR BI-RADS Ultrasound Lexicon

Shape Orientation Margin

Lesion Boundary

Posterior Acoustic Features

Mass Shape

Round Oval

Irregular

Mass Margins

Spiculated

Circumscribed

Angular

Microlobulated Indistinct

Mass orientation

Parallel Non Parallel

Parallel

Thick echogenic border

Taller than wider

Abrupt interface

Wider than taller

Mass ‘lesion boundary’

Mass echopattern

Anechoic Hypoechoic

Hyperechoic Complex Cystic /Solid

Mass ‘posterior acoustic features’

Posterior acoustic

enhancement

Posterior acoustic

shadowing

BIRADS Classification (Ultrasound) Category Description Examples

0 Incomplete Postop scar/recurrence

1 Negative Normal ultrasound

2 Benign finding Simple cysts, breast implants, stable postsurgical changes, and

probable fibroadenomas noted to be unchanged at

successive US studies

3 Probably benign finding A solid mass with circumscribed margins, an oval shape, and

parallel orientation

4 Suspicious abnormality Solid masses with indeterminate features, complicated cysts and

some complex cystic and solid masses (eg, clinically apparent

abscesses)

5 Highly suggestive of malignancy Spiculated mass

6 Known malignancy Biopsy-proven

Challenges in assigning Final category

Age of the patient Palpable probably

benign lesions

Abscess /

Hematoma

Differing categories

on various imaging

modalities

Ultrasound imaging Palpation

Morphological information Estimate tissue stiffness Subjective

Tissue Elasticity

Imaging

Strongly correlated to

pathology

Elastography

Ultrasound Elastography

Benign : fibroadenoma 18.1 kPa Malignant : Invasive ductal Ca 167 kPa

Ultrasound Elastography

A case of organized abscess following non

lactational mastitis showing low elasticity values A simple cyst on elastography

showing a signal void

Clinical Implications

Better characterization of

BIRADS 3 & 4 lesion

Increased diagnostic confidence

May avoid unnecessary biopsies

Differentiation of solid from

atypical cystic lesions

Complex solid cystic lesions

guiding site of biopsy

US: BIRADS 3 Lesion

SW Elastography : High elasticity

value

(186.52kPa)

Biopsy : Invasive ductal carcinoma

Breast MRI

Well established adjunctive modality

Dedicated breast coils

Standardized protocols and ACR reporting lexicon

MR compatible needles

Enough literature available

Sensitivity high, Specificity moderate

Current Indications of MRI

Screening Women at a high risk of breast cancer

Diagnosis Equivocal mammogram / US

Occult breast primary in pts with axillary metastases

Staging Extent of cancer, Multifocal/ Multicentric/ Contralateral

Chest wall invasion

Infiltrating lobular cancer

Treatment Early assessment of response to NACT

Residual disease after completion of NACT

Differentiation of recurrence/ postop scar

Technical Requirements

High-field strength (1.5T)

Gadolinium-DTPA injection

Dedicated bilateral breast coil

Good fat suppression

High-resolution 3D gradient echo pulse sequence

DCEMRI Routine Sequences

Pre-contrast T1W Pre-contrast T2W

Post-contrast T1W axial Post-contrast T1W Sagittal Axial MIP

Time-intensity Curve

ACR BI-RADS MRI Lexicon

Focus

Mass

Morphology

Precontrast Signal intensity

Contrast kinetics

Non masslike enhancement

Distribution

Symmetry

Mass shape

P

robabili

ty o

f m

alig

nancy

Round

Oval

Irregular

Lobulated

Mass margins

Smooth Spiculated; 80% malignant

Mass - Internal enhancement

Homogeneous Heterogeneous Nonenhancing

septations Rim enhancement

Enhancing

septations

Mass- Kinetic Analysis

ROI placed within the fastest-

enhancing part of a lesion

Initial enhancement

Slow, medium, rapid

Delayed enhancement

Persistent rise, plateau, washout

Mass - Signal intensity curves

Type I

6% Malignant

Type II

Type III

30-75% malignant Morphology First !

Non masslike enhancement

Descriptors

Distribution Internal

enhancement

Symmetry

Kinetic analysis misleading for non-mass like enhancement

Non-mass like enhancement -

Distribution

Linear

31%malignant

Ductal

60% malignant

Segmental

78% malignant

Regional

21% malignant

Focal

Non masslike enhancement-

Symmetry

Bilaterally Symmetrical Bilaterally Asymmetrical

Scintimammography

Breast Specific Gamma Imaging

PET

Further reading

ACR Guidelines: Breast Imaging