How to Approach Breast Ultrasound

Mai Elezaby¹, MD

Cecelia Marcado², MD

Monica Sheth³, MD

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1. University of Wisconsin School of Medicine and Public Health
2. NYU Langone Health
3. NYU Langone Health

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Indications

Patients present for breast ultrasound for either screening or diagnostic purposes

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Screening:

• Asymptomatic patients with high risk for breast cancer and contraindication to screening MRI
• Asymptomatic patients with dense breast (ACR categories C or D) +/- ↑ risk of breast cancer

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Diagnostic-Problem Solving for the evaluation of:

• Breast symptoms: lump, pain, nipple discharge, skin retraction
• Patients < 30 years, US first, otherwise start with MG
• Mammographic abnormality
• MRI abnormality

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Equipment

Standard US Equipment:

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• Monitor - displays images

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• Keyboard - houses controls to optimize images - focal zone, depth, spatial compounding, gain, harmonics, etc. to clarify images

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• Measurement tools and doppler imaging to provide additional details.

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• Transducers - come in various frequencies
• lower frequency transducers having deeper penetration of tissue.

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Technique: Optimize Imaging

• High frequency, linear array transducer
• with center of frequency of at least 10MHz
• with maximum frequency 12-18 MHz

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• Field of view - reach chest wall but not beyond

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• Overall gain - set so that fat is gray

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• TGC - increase with increasing depth

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• Focal zone - set at lesion
• Most transducers allow for multiple focal zones
• Increase resolution of lesion with one focal zone

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Focal Zone

Technique: Patient Positioning

• Positioning is key to immobilize breast tissue and aid with scanning

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• Good positioning includes:
• Arm above the head - helps thin and spread breast tissue for improved penetration
• Lying supine to evaluate medial tissue
• Lying supine oblique for lateral breast and axilla evaluation
• Wedges can be used to provide additional support

Approach: Scanning planes

Document findings in two planes (transverse/longitudinal or radial/antiradial). Images below demonstrate orientation of the transducer (blue rectangle) in relation to the breast

Lesion Location:

Findings in ultrasound are given two location identifiers:

1) Clock face position 2) Distance (cm) from the nipple ssssssssssssssssssssssssssssssssssssssssss(center of probe to nipple)

Lesion Location:

Now let’s practice. What is the clock face position of the following findings?

Right Breast:

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Left Breast:

Right

Left

2:00

7:00

Normal Anatomy

Skin

*Fat - hypoechoic (gray)

Fibroglandular tissue - echogenic (light gray/white)

Skeletal muscle

(Pectoralis muscle/chest wall)

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Ribs

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Lung Pleura

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Important to note that echogenicity of ultrasound findings are described relative to echogenicity of breast fat.

Relationship of tissue depth on MG and US

Ultrasound Reporting: BIRADS

https://www.acr.org/~/media/ACR/Documents/PDF/QualitySafety/Resources/BIRADS/Posters/BIRADS-Poster_36x24in_F.pdf?la=en

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Tissue Composition

(Screening Ultrasound)

Homogeneous background

echotexture - fat

Heterogeneous background echotexture

Homogeneous background echotexture - fibroglandular

On screening ultrasound exams, documentation of the patient’s tissue background echotexture is a standard component of report.

Ultrasound Findings

Mass - Shape

Oval

Round

Irregular

Lower likelihood of malignancy (LOM)

Higher LOM

Ultrasound Findings

Mass - Margin

Circumscribed

Spiculated

Microlobulated

Indistinct

Angular

More suspicious

Ultrasound Findings

Mass - Echogenicity

Anechoic

Hypoechoic

Hyperechoic

• Brighter than FAT (light gray-white)
• Usually benign

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• No internal echoes (black)
• Mostly indicates simple cyst

• Darker than FAT
• Most of masses

Ultrasound Findings

Mass - Echogenicity

Isoechoic

Complex Solid and cystic

Heterogeneous

• Similar to FAT
• Typically benign

• Highly suspicious for malignancy

Ultrasound Findings

Mass - Orientation

More common with benign masses

More common with malignant masses

wider than tall

Taller than wide

Ultrasound Findings

Mass - Posterior Features

Tissue posterior to mass is brighter

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Tissue posterior to mass is darker

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None

Shadowing

Enhancement

Combined

MASS SUMMARY

CYSTS

MLO

CC

Simple Cyst

• Anechoic
• Smooth internal wall
• Posterior enhancement
• No internal vascularity
• Benign-No follow up needed

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CYSTS

MLO

CC

Complicated Cyst

• Mixed echogenicity
• Fluid/fluid level
• Floating debris
• Posterior enhancement
• No internal vascularity
• Benign-No follow up needed

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CYSTS

MLO

CC

Clustered Microcysts

• Multiple small cysts (< 2-3mm)
• Imperceptible wall
• No internal vascularity
• Benign - No follow up needed
• If solid component→ biopsy

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CALCIFICATIONS

MLO

CC

In a mass

Outside a mass

Intraductal

Calcifications appear as small echogenic foci on ultrasound.

CALCIFICATIONS

MLO

CC

Large dystrophic calcifications may appear echogenic superficially (arrow head), with marked posterior shadowing (long arrow).

Dystrophic calcification on US

Dystrophic calcification on MG

LYMPH NODES

MLO

CC

Eccentric cortical thickening ≥ 3mm

Attenuated to

complete loss of

fatty hilum

Normal

Maintain fatty hilum

Thin uniform cortex

Abnormal