Diagnostic ultrasound ( PDFDrive )

764 PART III Small Parts, Carotid Artery, and Peripheral Vessel Sonography
RAD
A RT 12 2B B C
A AR
B C
FIG. 21.6 Mammary Duct: Spectrum of Normal Appearances. (A) With high spatial resolution, 90-degree angle of incidence, and perfect
centering, the duct appears to be composed of a central echogenic line (arrows) that represents the apposed walls of the collapsed mammary
duct. The surrounding isoechoic tissue represents loose periductal stromal tissue. Unfortunately, only a minority of the ducts seen have this trilaminar
appearance in the long axis and targetoid appearance in the short axis. Ducts that are slightly out of focus, coursing at an angle, or not perfectly
centered within the beam have a different appearance. The deeper duct (arrowheads) is too deep for the short-axis focal length of the transducer.
The central echo that represents the apposed walls of the collapsed duct is not seen. Only the isoechoic loose periductal stromal tissue can be
identiied. (B) This mildly ectatic duct (arrows) is shown in long axis (upper image) and short axis (lower image). The duct is now represented by
two hyperechoic lines that represent the anterior and posterior walls of the duct separated by secretions within the duct lumen. (C) This severely
ectatic duct (arrows) is shown in long axis (upper image) and short axis (lower image). As the degree of ductal ectasia increases, the walls of the
duct become more separated, and the loose periductal stromal tissue becomes more compressed and less apparent. In severe ductal ectasia the
periductal loose stromal tissue may no longer be visible.