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Key Concepts: 1. The lack of whole-liver explant correlation has led to an overestimation of the sensitivity of imaging tests for the diagnosis of HCC in the radiological literature. 2. Ultrasound is insensitive for the diagnosis of HCC in the cirrhotic liver and should not be used for the detection of focal liver lesions in this setting. 3. Although magnetic resonance (MR) imaging is more sensitive than multidetector 3-phase computed tomography (CT) for the diagnosis of regenerative and dysplastic nodules it is probably no better than CT for detection of HCC and has a lower false-positive rate. 4. Approximately 10-30% of nodules measuring <2 cm seen only on the hepatic arterial phase at CT or MR imaging represent small HCC and vigilant surveillance imaging is required as interval growth is the best indicator of malignancy., (Copyright 2006 AASLD.)

Our objective was to investigate the coexistence of vascular and biliary anatomic variants, the latter of which are known to increase the risk of biliary complications in living liver donor transplantation. A total of 108 consecutive liver donor candidates were examined by magnetic resonance (MR) imaging that included 2 MR cholangiography methods, T2-weighted MR cholangiography and mangofodipir-enhanced T1-weighted three-dimensional (3D) MR cholangiography, as well as gadolinium-enhanced MR angiography and venography of the liver. Images were interpreted by at least 2 investigators in consensus for definition of hepatic arterial, portal venous, and biliary anatomy. A subset of 51 subjects underwent laparotomy for right hepatectomy. Of the 108 subjects examined, 50 (46%) demonstrated normal hepatic artery, portal vein, and biliary anatomy. Variants of the hepatic artery were found in 27 of 108 (25%) subjects, of the portal vein in 12 of 108 (11%) subjects, and of the bile ducts in 30 of 108 (28%) subjects. Of the 27 subjects with hepatic arterial variants, 8 (30%) also had variant biliary anatomy. The association between hepatic arterial variants and biliary variants was not statistically significant (P >.5). However, of the 12 subjects with portal vein variants, 7 (58%) had biliary variants, and in 6 of 7 cases, the right posterior hepatic duct was anomalous. By chi-square analysis, the association between portal venous and biliary variants was significant (P =.012). In conclusion, over half of subjects with portal vein variants were found to have anomalous biliary anatomy, which always involved the hepatic ducts of the right lobe. The association between portal venous and biliary variants is statistically significant, while there is no significant association between hepatic arterial and biliary variants.

The sensitivity of magnetic resonance imaging (MRI) in patients who undergo transplantation for hepatocellular carcinoma (HCC) and cirrhosis is not known. We prospectively evaluated 24 patients with known HCC who underwent MRI and subsequent transplantation within 60 days (mean, 20 days). Using a phased-array coil at 1.5T, breath-hold turbo STIR and T2-weighted MR images were performed. Dynamic gadolinium-enhanced MRI was performed using a two- or three-dimensional gradient echo pulse sequence with images obtained in the hepatic arterial, portal venous, and equilibrium phases. The prospective interpretation of the MR study was directly compared with thin-section pathology evaluation of the explanted livers. All 24 patients had at least one HCC, and MR diagnosed tumor in 21 (88%) of these patients. On a lesion-by-lesion basis, MRI depicted 39 of 118 HCC for an overall sensitivity of 33%. MRI detected five (100%) of five lesions >5 cm, 20 (100%) of 20 lesions >2 cm but not exceeding 5 cm, 11 (52%) of 21 lesions between 1 and 2 cm, and three (4%) of 72 lesions <1 cm. Of the nine patients with carcinomatosis (innumerable lesions less than 1 cm), MR detected three lesions in one patient. Of the 15 dysplastic nodules found at pathology, MRI depicted a single 1.8-cm high-grade lesion, for a sensitivity of 7%. In conclusion, MRI is sensitive for the detection of HCC measuring at least 2 cm in diameter but is insensitive for the diagnosis of small HCC (<2 cm) and carcinomatosis.