MRI angiography is superior to helical CT for detection of HCC prior to liver transplantation: An explant correlation

Helical computerized tomography (CT) and magnetic resonance imaging (MRI) are used for staging of hepatocellular carcinoma (HCC) prior to curative treatments but underestimate tumor extension in 30% to 50% of cases when compared with pathologic explants. This study compares a new technology, MRI angiography (MRA), with triphasic helical CT in detection of HCC. Fifty cirrhotic patients, 29 with HCC, undergoing liver transplantation were analyzed. MRA was performed with a 3–D breath–hold fast spoiled gradient–echo sequence by using an effective section thickness of 2 to 2.5 mm. The gold standard was the pathologic examination (liver cut into 5–mm slices). One hundred twenty–seven lesions were identified at the explant: 76 HCC, 13 high–grade dysplastic nodules, 31 macroregenerative nodules, 7 hemangiomas. Diameter of the main HCC nodules was 29 ± 14 mm and 11 ± 7 mm for the 47 additional nodules. On a per nodule basis, sensitivity of MRA was superior to CT (58/76 [76%] vs. 43/70 [61%], respectively, P = .001). Sensitivity of MRA for detection of additional nodules decreased with size (>20 mm: 6/6 [100%]; 10-20 mm: 16/19 [84%]; <10 mm: 7/22 [32%]) and was superior to CT for nodules 10 to 20 mm (84% vs. 47%, P = .016). Nonspecific hypervascular nodules >5 mm at MRA were HCC in two thirds of the cases. In conclusion, MRA has a high diagnostic accuracy for HCC ≥ 10 mm and is more sensitive than triphasic helical CT in nodules sized 10 to 20 mm. MRA is the optimal technique for HCC staging prior to curative therapies. (Hepatology 2003;38:1034-1042).