on conventional US, often hypoechoic with posterior shadowing, similar to many malignant tumors.10 In essence, recurrent tumors will demonstrate angiogenesis (enhancement), whereas scars demonstrate minimal to no enhancement.
TABLE 34.1 Uses of Contrast Ultrasound in the Liver
related to a focal congenital vascular malformation.17 This results in a histologic mix of abnormally arranged non neoplastic hepatocytes, Kupffer cells, biliary ducts, and components of portal triads. Similarly to hemangiomas, FNH is usually asymptomatic and discovered incidentally.
Figure 34-6. Hepatocellular carcinoma (HCC) demonstrating arterial enhancement and washout (arrows). A: Intense early arterial enhancement. B: Contrast washout of HCC on later phase (4-minute delay).
The enhancement patterns should be similar to the tumor from which it originated and will have a different appearance than a normally enhancing vessel (an arterial tumor blush rather than discrete vessels)22 (Fig. 34-7). A marked washout in the portal and late phases may occur in metastatic portal vein thrombosis, up to an anechoic appearance, resembling bland thrombus in this vascular phase (Fig. 34-8).
washout on portal and late phases. Minimal enhancement of irregularly thickened bile ducts may be seen on the portal venous phase.