Prediction of histologic differentiation grade of hepatocellular carcinoma by magnetic resonance imaging with hepatospecific contrast agent

Background: To evaluate the predictive value at the hepatobiliary phase (HBP) magnetic resonance imaging (MRI) after gadobenate dimeglumine (Gd- BOPTA) injection for histologic grades of hepatocellular carcinoma (HCC). Materials and Methods: HCC patients who underwent Gd-BOPTA-enhanced MRI were analyzed and divided into four histologic grades of differentiation based on Edmonson-Steiner grade. Besides, HCC tumor differentiations grade I, II and III, IVwere defined as well-differentiated (WD), moderatelydifferentiated (MD), poorly-differentiated (PD), respectively. The clinical, pathological and imaging features of patients were assessed. Receiver operating characteristic (ROC) curve was to evaluate the significance between WD/MD HCC and PD HCC using the apparent diffusion coefficient (ADC), relative intensity ratio (RIR) of T1WI and T2WI (T1RIR, T2RIR), contrastenhancement ratio in arterial phase (CERA) and contrast-noise-ratio (CNR) in HBP (CNRhbp). Results: A total of 102 HCC patients were analyzed (grade I, n=19; grade II, n=30; grade III, n=30; grade IV, n=23). There was no statistical difference regarding to the pathological and clinical features among four grades. There were significant differences in CERA, CNRhbp, T1RIR, T2RIR and ADC values among the four HCC grades (all P<0.05). Based on ROC curve, comparison of the five quantitative MRI parameters indicated ADC (sensitivity 84.8%, specificity 82.6%, AUC 0.862) and CNRhbp value (sensitivity 78.5%, specificity 91.3%, AUC 0.916) could significantly distinguish the HCC histological grade. Conclusions: The ADC and/or CNRhbp value in HBP-MRI after GD-BOPTA injection might be as the significant quantitative parameters to distinguish HCC histological grade.