Abstract: Objective To evaluate the significance of magnetic resonance diffusion-weighted imaging (DWI) in predicting the histological grading of hepatocellular carcinoma (HCC). Methods Data of 27 patients with 27 surgically removed HCC who underwent preoperative conventional MRI and DWI examinations were retrospectively reviewed. The relationship between visual signal intensity and apparent diffusion coefficient (ADC) with histological differentiation of HCC was analyzed. Results Histopathologically, the tumors were classified into well-differentiated (n=6), moderately-differentiated (n=10) and poorly-differentiated (n=11). On DWI, 1 of the 27 HCCs appeared isointense, 9 slightly hyperintense, and the remaining 17 tumors hyperintense to the surrounding liver. Statistical analysis revealed no significant difference between visual signal intensity and histopathologic grade (P=0.758). The mean ADC value of the poorly-differentiated HCCs[(1.16±0.16)×10^-3mm²/s] was significantly lower than that of the well-differentiated HCCs[(1.43±0.09)×10^-3mm²/s] (P=0.004) and moderately-differentiated HCCs [(1.34±0.19)×10^-3mm²/s] (P=0.023). There was a significant correlation between the differentiation and the ADC value of the HCCs (r=-0.566, P=0.002). Conclusion DWI with ADC measurement of HCC may be a valuable imaging tool to noninvasively predict the differentiation of HCC. However, the histopathological grades of HCC are not correlated with the visualsignal intensity.

Key words: Magnetic resonance imaging, Diffusion-weighted imaging, Hepatocellular carcinoma, Histological grading, Apparent diffusion coefficient