P: 28 Decreased Mean Kurtosis in the Putamen Is a Diagnostic Feature of Minimal Hepatic Encephalopathy in Patients With Cirrhosis

Abstract

BACKGROUND: To prevent development of overt hepatic encephalopathy, early intervention for minimal hepatic encephalopathy (MHE) based on accurate diagnosis is essential. This study evaluated to investigate whether magnetic resonance diffusion kurtosis imaging (DKI) and diffusion tensor imaging (DTI) could detect brain microstructure abnormalities in MHE. The aim was to confirm whether brain microstructure abnormalities detected by magnetic resonance imaging were used as diagnosis of MHE. METHODS: Thirty-two subjects were prospectively examined with a 3-T MR scanner. Tract-based spatial statistics and region of interest analyses of diffusion imaging were performed to compare mean kurtosis (MK), fractional anisotropy (FA), and mean diffusivity (MD) values between patients with/without minimal hepatic encephalopathy. Diagnostic performance for detection of MHE was assessed with the receiver operating characteristic analysis. RESULTS: Ten subjects were diagnosed as MHE by neuropsychological testing. After exclusion of unsuitable subjects, we analyzed 9 subjects with MHE and 14 subjects without MHE. There were no significant differences in the sex, age, and etiology of liver cirrhosis (alcohol/HCV/NAFLD; 4/3/2 vs 7/3/4, P = 0.87) in the MHE group and non-MHE group. In TBSS, compared with FA and MD, MK detected the broadest area with significant changes in the white matter of patients with MHE (MK, 54.8%; FA, 34.3%; MD, 4.0%, respectively). Regarding ROI analysis in the basal ganglia, FA values of the caudate nucleus (CN), putamen (Put), and globus pallidus (GP) were significantly lower in the MHE group (0.15, 0.19, and 0.29, respectively) when compared with the non-MHE group (0.16, 0.21, and 0.32, respectively) (P = 0.012, 0.002, and 0.0001, respectively). In contrast, MD values in the basal ganglia showed no apparent differences between the groups. Subsequently, we performed ROC analysis on the sites where significant differences were found in the ROI analysis. Among the metrics, MK values of the Put achieved AUROC of 0.90, and sensitivity, specificity, positive predictive value, and negative predictive value of more than 80% (0.89, 0.86, 0.80, and 0.92, respectively) between the MHE and non-MHE groups. In conclusion, mean kurtosis on the putamen was a useful finding to distinguish patients with MHE among subjects with liver cirrhosis. CONCLUSIONS: DKI detects changes in the cerebral white matter and basal ganglia regions of the patients with MHE more sensitively than DTI. MK values in the putamen can be a useful marker for diagnosing MHE from cirrhotic patients without MHE.