Breast Ultrasound

Breast ultrasound is the principal adjunct to mammography for characterising masses, guiding biopsy and screening women with dense breasts. Using standardised BI-RADS ultrasound descriptors it distinguishes simple cysts from solid masses and stratifies solid lesions by malignancy risk. Elastography adds tissue-stiffness information, and the axilla is assessed for abnormal nodes.

Indications

Characterisation of a palpable lump or focal breast symptom
Further evaluation of a mammographic mass, asymmetry or architectural distortion
Supplemental screening in women with dense breasts or elevated risk
First-line imaging in young, pregnant or lactating patients
Image-guided biopsy, aspiration or localisation
Assessment of the axilla for nodal involvement

Contraindications & Cautions

No absolute contraindications; ultrasound is non-ionising and safe
Not a standalone replacement for mammography in general screening (limited for microcalcifications)
Operator-dependent and time-consuming for whole-breast surveys
Very large or fatty breasts may limit whole-breast coverage

Patient Preparation

No specific preparation required
Supine or supine-oblique position with the ipsilateral arm raised behind the head
Correlate with the mammogram and clinical site of concern before scanning
Mark and describe lesion location by clock position and distance from the nipple
For interventional procedures prepare a sterile field and obtain consent

Technique & Parameters

High-frequency linear transducer 12-18 MHz with a dedicated breast preset
Targeted radial and antiradial scanning of the lesion in two orthogonal planes
Whole-breast survey by quadrants/clock positions with overlapping sweeps when indicated
Colour or power Doppler to assess internal and peripheral vascularity
Shear-wave or strain elastography as an adjunct to increase specificity
Assess the axilla, infraclavicular and internal mammary regions for abnormal nodes

Systematic Review

Shape (oval, round, irregular) and orientation (parallel vs not parallel to the skin)
Margin (circumscribed vs not circumscribed: indistinct, angular, microlobulated, spiculated)
Echo pattern (anechoic, hypoechoic, isoechoic, complex cystic and solid, heterogeneous)
Posterior features (enhancement, shadowing, combined) and any calcifications
Vascularity on Doppler and stiffness on elastography
Associated features and axillary node cortical thickness/hilar effacement

Key Findings & Significance

Simple cyst: anechoic, circumscribed, thin wall with posterior enhancement (BI-RADS 2, benign)
Probably benign solid mass: oval, parallel, circumscribed, hypoechoic (favours fibroadenoma, BI-RADS 3)
Suspicious mass: irregular shape, non-parallel orientation, spiculated/angular margins, posterior shadowing (BI-RADS 4-5)
High stiffness on elastography and marked internal vascularity increase suspicion
Abnormal node: cortical thickening >3 mm, loss of fatty hilum, rounded shape
Complex cystic and solid mass warrants biopsy to exclude malignancy

Differential Considerations

Cystic lesion: simple cyst vs complicated cyst vs complex cystic and solid mass
Circumscribed solid mass: fibroadenoma vs phyllodes vs circumscribed carcinoma
Irregular hypoechoic mass: invasive carcinoma vs fat necrosis vs radial scar vs abscess
Shadowing lesion: carcinoma vs post-surgical scar vs fibrosis
Enlarged node: reactive vs metastatic vs lymphoma

Pearls & Pitfalls

Apply BI-RADS ultrasound descriptors and a final category to standardise risk and management
Non-parallel (taller-than-wide) orientation and non-circumscribed margins are strong malignant features
Confirm a suspected simple cyst by strict criteria before assigning BI-RADS 2; otherwise aspirate or biopsy
Elastography and Doppler raise specificity but do not override suspicious grey-scale morphology
Always correlate with the mammogram and inspect the axilla; microcalcifications are better seen on mammography

Structured Report

State indication, laterality, technique (targeted vs whole-breast) and correlation with mammography
Describe each lesion by BI-RADS descriptors with clock position and distance from the nipple
Report Doppler and elastography findings and axillary node status
Assign a BI-RADS final assessment category and recommend management (follow-up, biopsy, aspiration)
Give a concise impression addressing the clinical question

References

ACR BI-RADS Atlas, 5th Edition: Ultrasound
ACR-AIUM-SPR-SRU Practice Parameter for the Performance of a Breast Ultrasound Examination
Berg WA et al. ACRIN 6666: Supplemental Screening Ultrasound in Dense Breasts. JAMA/Radiology
Barr RG et al. WFUMB Guidelines on Breast Elastography

Educational clinical decision support only. Protocols vary by institution and equipment; always confirm with a qualified radiologist and local guidelines before clinical use.

Breast Ultrasound

📋 Indications

⛔ Contraindications & Cautions

🧑‍⚕️ Patient Preparation

⚙️ Technique & Parameters

🔎 Systematic Review

🩻 Key Findings & Significance

🧠 Differential Considerations

💡 Pearls & Pitfalls

📝 Structured Report

📚 References