ULTRASOUND OF THE BREAST - Normal
|Normal breast tissue showing:
i.the premammary zone (skin and overlying breast fat)
ii.the mammary zone (fibroglandular tissue)
iii.the retro-mammary zone (predominantly fat and the muscles of the chest wall)
|Normal lactating breast tissue:
The prominent fluid filled ducts and their echogenic epithelial lining is readily visible.
ULTRASOUND OF THE BREAST - PROTOCOL
ROLE OF ULTRASOUND
Ultrasound is a valuable diagnostic tool in assessing the following indications:
•Investigating a palpable lump
•Follow up of known lesion
•Infection or mastitis
•Guidance for biopsy or hookwire localisation
Ultrasound increasingly enlisted as part of a comprehensive screening program along side mammography.
- Extremely large, mobile breasts will be difficult to scan thoroughly.
- Post injury, surgery or biopsy, the resultant haematoma will reduce detail and may obscure pathology.
EQUIPMENT SELECTION AND TECHNIQUE
- Breast u/s requires a high frequency transducer 8-15 MHz.
- Ideally a wide footprint probe.
- A lower frequency transducer may be required for the larger attenuative breasts, inflammatory masses and the axilla.
- The use of a stand off may be required for nipple, superficial/or skin lesions.
- Low PRF colour and spectral doppler capabilities for assessing vascularity of lesions.
- Patient supine
- You may need to roll the patient slightly to 'spread' the breast evenly. Elevate the side being scanned with a wedge under the shoulder.
- Raise the ipsilateral arm over the patient's head.
- It is important to correlate the ultrasound with any palpable lumps indicated by the patient. Accordingly, if the patient can only identify the lump when she is erect than rescan the patient erect.
The most common scanning technique is to initially scan using the grid scanning pattern, followed by a radial (clock face) technique for the hard copy imaging.
GRID SCANNING PATTERN
- Scan up and down the breast in rows, making sure you overlap each row slightly to ensure no breast tissue is overlooked.
|Grid scanning pattern: phase 1.
||Grid scanning pattern: phase 1.
- Begin in the upper outer quadrant, scanning in transverse. Slide inferiorly from top to bottom.
- Move across and repeat the sweep inferior to superior.
- Repeat this across the breast.
- Rotate into a sagittal plane and repeat the pattern.
A variation, particularly in larger or mobile breasts, is to apply the grid pattern quadrant by quadrant.
RADIAL SCANNING PATTERN (Clock-face)
|The scan direction for Radial breast scanning.
||Hard copy imaging of regions of interest should be taken in 2 planes.
- The breast is scanned and described as a clock-face.
- Begin at 12 o'clock in a sagittal plane with the toe of the probe at the nipple.
- Scan by rotating the probe around the nipple.
- Depending on breast size, a second pass further from the nipple may be required.
- If pathology is identified, rotate the probe 90degrees in the 'anti-radial' plane.
BREAST IMPLANT IMAGING
- Should be scanned with the patient positioned as above.
- Treat the scan as a 2-fold examination:
- The breast tissue.
- The deeper implant. This may require lower frequency or a curved probe to investigate.
The implant should be anechoic with well defined margins. Folds are commonly seen in the implant surface.
Also, small traces of simple fluid will be seen overlying the implant but is contained by the overlying fibrous capsule that contains the implant. This fluid is routinely seen within the implant folds (see image below).
Most saline implants will have a small valve visible (see image below)
||For a link to breast implant types, valves and history.
|The normal appearance of a fold in an implant with normal physiological amount of capsular free fluid. The mammogram below shows the typical appearance of folds.
||A normal finding of an implant 'valve'. Also visible in the mammogram below.
|The typical appearance of folds in a breast implant.
BASIC HARD COPY IMAGING
A breast series should include the following minimum images:
- 12 O'Clock
- 2 O'Clock
- 4 O'Clock
- 6 O'Clock
- 8 O'Clock
- 10 O'Clock
- Axillary tail
Document any pathology found in 2 planes, including measurements and any vascularity.
Note the size, depth and distance from the nipple.