Ultrasound
Breast ultrasound is a non-invasive, radiation-free imaging technique that uses sound waves to evaluate breast tissue. It serves as a valuable adjunct when mammography is unavailable, inconclusive, or for targeted follow-up of clinical findings. Below, you’ll find detailed information on ultrasound use, screening protocols, and interpretation to aid in clinical decision-making.
Ultrasound (US)
What is it?
Breast ultrasound is a non-invasive imaging technique that uses high-frequency sound waves to evaluate specific areas of the breast.
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How Does it Work?
Ultrasound generates sound waves that penetrate breast tissue and reflect to the transducer at varying intensities based on the tissue's composition. The returning echoes create a detailed image, allowing for:
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Differentiation of Tissue Types: Identifies fluid-filled cysts versus solid masses.
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Morphological Assessment: Evaluates mass shape, margin, and echogenicity to help distinguish benign from suspicious lesions.
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Targeted Imaging: Focuses on areas of concern identified on mammography or physical exam, aiding in diagnostic clarity.
Ultrasound does not assess overall breast density, as this requires mammographic imaging.
Best for:
Breast ultrasound is particularly effective in:
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Dense Breasts: Provides supplemental screening in women where mammography sensitivity is reduced due to dense glandular tissue.
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Targeted Evaluation: Further characterizes mammographic findings such as focal asymmetries, architectural distortions, or palpable abnormalities.
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Contrast-Free Screening: Offers a non-contrast alternative for patients who are contraindicated for or decline MRI.
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Resource-Limited Settings: Provides accessible supplemental screening in areas where advanced imaging modalities like MRI are unavailable.
Clinical Performance:
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Hand-Held Ultrasound (HHUS): Sensitivity ranges from 33-52% and specificity between 91-98% for women with ≥20-25% lifetime breast cancer risk. The variability is operator dependent. (1)
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Automated Breast Ultrasound (ABUS): Demonstrates comparable sensitivity and specificity to HHUS but minimizes operator variability and provides standardized whole-breast imaging. (2)
Limitations:
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Operator Dependence: The accuracy of HHUS relies heavily on the expertise of the operator, making quality control essential.
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Detection Limitations: Ultrasound is not sensitive to microcalcifications, often an early indicator of malignancy.
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Higher False Positives: Ultrasound has a higher rate of benign findings, leading to increased follow-up imaging and biopsies.
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Regulatory Status:
Breast ultrasound is not routinely recommended for whole-breast screening but is widely used as a diagnostic and supplemental imaging modality.
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