Diffusion kurtosis imaging and diffusion-weighted imaging in assessment of liver fibrosis stage and necroinflammatory activity

Purpose: To investigate and compare the diagnostic value of diffusion kurtosis imaging (DKI) with diffusion-weighted imaging (DWI) in assessing and quantifying hepatic fibrosis. Methods: Thirty rats were divided into the control group (n - 6) and the fibrosis experimental groups (n - 6 per group) with CCl4 administration for 2, 4, 6, and 8 weeks. Liver fibrosis stage (S) and necroinflammatory activity grade (G) were histopathologically determined. DKI and DWI were performed; mean apparent diffusion (MD), mean kurtosis (MK), and apparent diffusion coefficient (ADC) values were calculated. DKI parameters were compared with ADC values according to G/S scores. Results: Strong inverse correlations were found between the degree of fibrosis and both MD and ADC (r = -0.840 and r = -0.760), while only weak correlation existed in MK (r = 0.405). ROC analyses demonstrated the AUC in MD, MK, and ADC of 0.862, 0.684, 0.817 for identifying mild and severe fibrosis, and 0.757, 0.675, 0.733 for non-cirrhosis and cirrhosis, respectively. The degree of fibrosis was significantly correlated with alpha-smooth muscle actin (alpha-SMA) (P < 0.0001); a-SMA had strong inverse correlation with MD (r = -0.723), moderate inverse correlation with ADC (r = -0.613), and very weak correlation with MK (r = 0.175). Additionally, MD was strongly correlated with the necroinflammatory activity (r = -0.758), ADC was moderately correlated (r = -0.492), and MK was weakly correlated (r = 0.254). Conclusion: DKI may provide added information and serve as a valuable tool for the characterization and surveillance of liver fibrosis in a non-invasive manner.