The expression of transporter OATP2/OATP8 decreases in undetectable hepatocellular carcinoma by Gd-EOB-MRI in the explanted cirrhotic liver.

PURPOSE The aim of this study is to evaluate the detectability of hepatocellular carcinoma (HCC) in the explanted cirrhotic liver using gadoxetic acid-enhanced magnetic resonance imaging (Gd-EOB-MRI) and the degree of organic anion transporter OATP2/OATP8 (OATP1B1/1B3) HCC which could not be preoperatively detected by multi-detector computed tomography (MD-CT) and Gd-EOB-MRI. METHODS Eleven patients (HBV 3, HCV 7, nonBnonC 1) out of 145 recipients of liver transplantation were analyzed. The detectability by each imaging modality and the expression of OATP2/OATP8 of HCC were analyzed using the whole liver thin sliced histological and immunohistochemical examination retrospectively. RESULTS The imaging examination detected 17 lesions of HCC by MDCT and/or Gd-EOB-MRI. Only one lesion detected by Gd-EOB-MRI had well differentiated and minute (7 mm) HCC. However, the histological examination revealed newly 11 lesions and one false-positive lesion of HCC in the explanted livers. The median diameter of the preoperatively undetectable HCC by imaging was 8 mm (2-12). The histological characteristic of the preoperatively undetectable HCC was well differentiated HCC (10/11). The accuracy rate in MDCT and Gd-EOB-MRI was 53.6 % (15/28) and 57.1 % (16/28). The rate of positive predictive value in MDCT and Gd-EOB-MRI was 93.7 % (15/16) and 94.2 % (16/17), respectively. The expression of OATP2/OATP8 in the preoperatively undetectable HCC was negative in nine lesions, was weak positive in two lesions. CONCLUSIONS The detectability of Gd-EOB-MRI is almost equal to MDCT in a cirrhotic liver. Small HCCs were difficult to detect even with Gd-EOB-MRI. The transporter of OATP2/OATP8 was less expressed in the preoperatively undetectable HCCs.