Diagnostic ultrasound ( PDFDrive )

778 PART III Small Parts, Carotid Artery, and Peripheral Vessel Sonography
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A
Supine
LT 300 1B long
Upright
B
FIG. 21.25 Fat-Fluid Level. The lipid layer is echogenic compared with cyst luid and moves within the cyst to its nondependent part when
the patient changes position. (A) The echogenic lipid layer (*) loats to the nondependent anterior wall of the cyst, and the interface is oriented
horizontally when the patient is scanned in the supine position. (B) The echogenic lipid layer has loated to the new nondependent superior wall,
and the interface is oriented vertically when the patient is in the upright position and the cyst is scanned longitudinally.
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A
B
FIG. 21.26 Acorn Cysts of Two Different Types. (A) Sonogram shows two cysts that have crescentic echogenic thickening along the anterior
wall, resembling the caps on acorns. The echogenic material in the left acorn cyst (#) is loating lipid debris, whereas the echogenic material along
the anterior wall of the right acorn cyst (*) is papillary apocrine metaplasia (PAM). Unfortunately, the distinction cannot be made from a single
image obtained in the supine position. Changing position can help but often takes 5 minutes; with power Doppler vocal fremitus, the distinction
can be made virtually instantly. Having the patient hum in a deep voice creates an orange artifact on power Doppler in normal breast tissues and
within any mural nodules or thick septations that are attached to the wall of the cyst, but not within unattached debris. (B) Power Doppler ultrasound
image shows that the vocal fremitus artifact does not ill the echoes caused by the unattached debris level in the left acorn cyst (#) but does ill
the attached echogenic PAM (*) within the right acorn cyst.