Diagnostic ultrasound ( PDFDrive )

120 PART II Abdominal and Pelvic Sonography
A
B
C
D E F
G
H
I
FIG. 4.55 Hepatocellular Carcinoma: Spectrum of Appearances. (A) Small, focal hypoechoic nodules. (B) Multifocal hypoechoic nodules,
which may be dificult to differentiate from the background cirrhotic nodules. (C) Focal echogenic nodule mimicking hemangioma. (D) Large
echogenic nodule in a cirrhotic liver. (E) Large mixed-echogenic mass. Hypoechoic regions corresponded at pathology to areas of necrosis.
(F) Large lobulated mass with central hypoechoic region suggesting a scar. (G) Expansive tumor illing the portal vein is the only observation on
the sonogram. (H) Small cirrhotic liver showing exophytic tumors. (I) Supericial mass of mixed echogenicity in a young patient with hepatitis B
presenting with spontaneous liver rupture.
cavernous hemangiomas, and lipomas. 175,176,179 Intratumoral fat
also occurs in larger masses; because it tends to be focal, it is
unlikely to cause confusion in diagnosis. Patients with rare surface
lesions may present with spontaneous rupture and hemoperitoneum
(Fig. 4.55I).
Studies evaluating focal liver lesions with duplex Doppler
and CDFI suggest HCC has characteristic high-velocity signals. 180-
182
Doppler sonography is excellent for detecting neovascularity
within tumor thrombi within the portal veins, diagnostic of
HCC even without demonstration of the parenchymal lesion
(Fig. 4.56).
CEUS is much more sensitive for the detection of lesional
vascularity than is color Doppler (Table 4.4). Lesions are hypervascular
(Videos 4.10 and 4.11), oten showing dysmorphic vessels
(Fig. 4.57) and frequently showing unenhanced regions representing
either necrosis or scarring. 183,184 In the portal venous phase,
lesions show washout, such that they are less enhanced than the
adjacent liver (see Fig. 4.44). his washout is characteristically