Article ID: 2020-1711
Hepatobiliary specific contrast medium Gd-EOB-DTPA-enhanced MRI (EOB-MRI) is excellent for the detection and characterization of nodular lesions and plays an important role in the diagnosis of hepatocellular carcinoma (HCC). Gd-EOB-DTPA is received by normal hepatocytes, and then, excreted into bile ducts, under mediation by hepatocyte membrane transporters. The expression of uptake transporter organic anion transporting polypeptide 1B3 (OATP1B3) correlates with the enhancement ratio in the hepatobiliary phase of HCC. Consequently, OATP1B3 is the main uptake transporter of Gd-EOB-DTPA in HCC. The hepatobiliary phase of EOB-MRI can sensitively detect pathologically early HCC as a hypointense nodule, because the OATP1B3 expression decreases at an early stage of multistep hepatocarcinogenesis. Hypervascular HCC commonly presents hypointensity in the hepatobiliary phase with the decrease in the OATP1B3 expression ; however, approximately 10% of HCC atypically demonstrates hyperintensity, owing to OATP1B3 overexpression. HCC presenting hyperintensity in the hepatobiliary phase is a unique genetic subtype of HCC with a biologically less aggressive nature and mature hepatocyte-like molecular/genetic features. The interaction between β-catenin signaling and hepatocyte nuclear factor (HNF) 4α may plays an important role in the OATP1B3 expression and less aggressive biological nature of the hyperintense HCC in the hepatobiliary phase. Thus, EOB-MRI is crucial for the detection and characterization of HCC as well as for personalized medicine, such as an imaging biomarker.
