Diagnostic ultrasound ( PDFDrive )

794 PART III Small Parts, Carotid Artery, and Peripheral Vessel Sonography
A B C
FIG. 21.51 Hypoechoic Carcinomas. Malignant nodules are often markedly hypoechoic in comparison to fat. Hypoechogenicity can be the
result of (A) high cellularity and high content of hyaluronic acid within the extracellular matrix, or (B) intense acoustic shadowing associated with
invasive carcinomas. (C) Necrosis within the lumen of tumor-containing ductules can cause marked hypoechogenicity in lesions composed of pure
ductal carcinoma in situ (DCIS).
Fund
Harm
A
RT BR 930 3B RAD
B
RT BR 930 3B RAD
FIG. 21.52 Harmonic Imaging Improves Mass Visibility. (A) Nodules that are isoechoic with surrounding tissues and dificult to identify with
fundamental imaging (arrows) often appear (B) markedly hypoechoic and more conspicuous (arrows) when viewed with harmonics.
Calciications that are narrower than the beam width do not
cast acoustic shadows, appear larger than their true size, and
appear less echogenic than their true echogenicity. Most benign
calciications lie within a fairly echogenic background, so that
when volume is averaged with the surrounding echogenic tissues,
they are no longer bright enough to be identiied sonographically.
Malignant calciications lie within rather homogeneously
hypoechoic tumor substance and remain visible even though
they are subject to volume averaging with surrounding tissues.
hus sonography can generally demonstrate a higher percentage
of malignant than benign microcalciications.
Associated Features
Other indings that can be associated with malignancy but are
less speciic than the suspicious features listed earlier include
architectural distortion, skin changes, edema, and elasticity. hese