Targeted breast ultrasound
Area of clinical concern, with axilla where malignancy is suspected
When to use it
- Palpable breast lump under about 40, as the first-line study.
- Targeted assessment of a mammographic or clinical abnormality at any age.
- Assessment during pregnancy and lactation.
Technique
- High-frequency linear transducer, typically 10-18 MHz with a broad-bandwidth breast preset; the focal zone is set at the depth of the lesion and the field depth kept shallow enough that the lesion fills a useful part of the image.
- Patient supine or in a posterior oblique position with the ipsilateral arm raised above the head, which flattens the breast against the chest wall and reduces the tissue depth the beam must traverse. The oblique roll is essential for the lateral breast and for a large or ptotic breast.
- The area of clinical concern is scanned with the patient indicating the lump, and the sonographer's free hand can be used to fix a mobile lesion. Any lesion found is imaged in two orthogonal planes and measured in three dimensions, and its position recorded by clock face, distance from the nipple, and depth.
- Lesions are characterised against BI-RADS ultrasound descriptors — shape, orientation relative to the skin (taller-than-wide being the suspicious one), margin, echo pattern, and posterior features — and a BI-RADS assessment category is assigned, since that category and not the prose is what drives biopsy.
- The ipsilateral axilla is examined whenever malignancy is suspected, looking for cortical thickening, an eccentric cortex and loss of the fatty hilum; a suspicious node is sampled at the same visit in most services.
- Colour or power Doppler for internal vascularity, and elastography where available as an adjunct — neither overrides the greyscale morphology, and neither is a reason to downgrade a suspicious lesion.
- In pregnancy and lactation the technique is unchanged but the background is diffusely hyperechoic and glandular; scanning shortly after feeding or expressing reduces the engorgement that otherwise obscures a mass.
Where it goes wrong
- A negative ultrasound does not exclude malignancy in a clinically suspicious lump — triple assessment continues regardless of imaging.
Clinical questions that reach this study
Contrast
None