Fig. 3.

Classification of tumor image based on RER and visual signal intensity. Typical nodular images on hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI were presented. We defined HCC nodules with RER <0.9 as hypointense nodules, HCC nodules with RER >0.9 as higher enhancement nodules. a Typical hypointense HCC nodules with RER <0.9: this enhancement pattern was seen in a typical HCC, clearly lower signal intensity than the background liver on hepatobiliary phase. b Typical higher enhancement HCC nodules with RER >0.9: this enhancement pattern was seen in a green hepatoma, clearly higher signal intensity than the background liver on hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI. Some of them, heterogeneous intensity HCC nodules have been including, mixed regions of slightly higher signal intensity on the hepatobiliary phase. It is difficult to measure RER in this type of tumors. In this study, RER was measured by setting ROIs over the entire tumor. Gd-EOB-DTPA, gadolinium-ethoxybenzyl-diethylenetriamine; MRI, magnetic resonance imaging; HCC, hepatocellular carcinoma; RER, relative enhancement ratio; ROI, region of interest.