Liver Magnetic Resonance Diffusion Kurtosis Imaging For Quantitativly Evaluation Of Liver Fibrosis:An Experimental Study

Objective: To investigate the associations of liver magnetic resonance(MR) diffusion kurtosis imaging(DKI) related parameters with histological stage of liver fibrosis in rabbit model.Methods: Sixty-four healthy New Zealand white rabbits(56 rabbits in experimental group, 8 rabbits in control group) were enrolled in this study. Rabbit model of hepatic fibrosis was created by intraperitoneal injection of carbon tetrachloride(0.1 ml/kg,twice a week), respectively. The rabbits in control group were injection of normal saline with the same dosage and same frequency as rabbits in experimental group. MR DKI(b = 0, 500, 1000 s/mm2) was performed at the 6th, 8th, 10 th and 12 th week after beginning of modeling liver fibrosis. Liver mean kurtosis(MK), fractional anisotropy(FA) and mean diffusion(MD) were obtained on DKI. The rabbits were sacrificed in 24 hours after MRI scans, liver pathologic evaluation was performed and pathological specimens were scored using METAVIR classification system. Subsequently, statistical analysis was performed on SPSS 13.0 to evaluate the association of DKI related parameters with histological stage of liver fibrosis.Results:(1) With increasing stage of fibrosis, FA and MK values increased and MD values decreased(r = 0.512, 0.567 and-0.574, respectively; all P < 0.01).(2) FA, MD and MK values could distinguish F0 from F4, F0 from F3 and F1 from F4; FA value could distinguish F0 from F2 and F2 from F4; MD value could distinguish F0 from F2 and F1 from F3; MK value could distinguish F1 from F3 and F2 from F4(all P < 0.05).(3) Areas under receiver operating characteristic curve(AUCs) of liver DKI parameters was 0.925 or more for distinguishing between F0 and F4, 0.778 or more for distinguishing between F0 and F3, and 0.875 more for distinguishing between F1 and F4. Among these parameters, MK value was the best parameter for distinguishing liver fibrosis F1 from F3 and F1 from F4 with AUC of 0.847 and 0.950, respectively; FA value was the best parameter for distinguishing F0 from F4 and F2 from F4 with AUC of 0.950 and 0.860, respectively; MD was the best parameter for distinguishing F0 from F2 and F0 from F3 with AUC of 0.813 and 0.917, respectively。Conclusions: Liver FA, MD and MK values in DKI might be indicators to discriminate the stage of liver fibrosis. Among these parameters, MK value was the best parameter for distinguishing liver fibrosis F1 from F3 and F1 from F4; FA value was the best parameter for distinguishing F0 from F4 and F2 from F4; MD was the best parameter for distinguishing F0 from F2 and F0 from F3.