IMAGING OF COMPLICATIONS IN LIVER-TRANSPLANTATION

Hepatic transplantations are being performed with increasing frequency , leading to greater demand for accurate evaluation of related complic ations. Ultrasonography (US) is the primary screening technique for de tection of vascular complications of hepatic transplantation; angiogra phy is used to confirm the US findings or when the US study is subopti mal. Hepatic artery thrombosis, the most common (as high as 42% of ped iatric cases; 4%-12% of adult cases) and important vascular complicati on, may be associated with bilomas, infarcts, or abscesses at gray-sca le US and absence of proper hepatic and intrahepatic arterial flow at Doppler analysis. Hepatic artery stenosis (seen in 11% of cases) is su spected if a focal accelerated velocity of greater than 2-3 m/sec with turbulence is seen at or distal to the stenosis or if a tardus parvus pattern of intrahepatic arterial flow is seen. In cases of inferior v ena cava thrombosis and stenosis, US may show echogenic thrombus or ob vious narrowing, with a substantially increased flow velocity through the stenosis or reversal of flow in the hepatic veins. Biliary complic ations occur relatively often (13%-25% of cases) after liver transplan tation; bile leakage and biliary stricture, the most common biliary co mplications, are seen as a fluid collection and a stricture, respectiv ely. Although acute rejection is one of the most serious complications affecting graft survival, it cannot be reliably detected with availab le diagnostic tests or radiologic methods.