Objective: Low grade cerebral edema is a major complication inpatients with minimal hepatic encephalopathy (MHE).MR imaging offers arange of capabilities for assessing the low grade brain edema.Our purposewas to quantitatively explore the structural abnormalities of grey matter(GM) and white matter (WM) in patients with MHE by using diffusiontensor imaging (DTI) and correlate them with blood ammonia level andneuropsychological (NP) tests. 　　Materials and methods: Eleven cirrhotic patients with MHEdiagnosed by NP tests and 14 sex, age, and education-matched healthycontrols (HC) recruited in this study.All subjects participated in NP testsand MRI scans including conventional T1, T2 weighted imaging, highresolution T1-weighted 3D anatomical images, and DTI.Laboratoryparameters, including prothrombin time, protein metabolism tests, andvenous blood ammonia, were obtained from all patients with MHE withinone week before MR scanning.Group differences in mean diffusivity (MD)and fractional anisotropy (FA) of GM and WM were compared by usingvolume based analysis (VBA), the correlation with blood ammonia leveland NP tests were analyzed using REST method. 　　Results: The regions of decreased FA values in MHE patients werebilateral temporal lobe (mid temporal gyrus), bilateral insular region, rightthalamus, right frontal lobe, bilateral cerebellum, right rolandic operculum,left cuneus, right parietal lobe and bilateral supplementary motor area. While the increased MD values were found in the following GM and WMareas: bilateral middle temporal gyrus, bilateral frontal gyrus, left pallidus,right pre and postcentral gyrus, bilateral mid cingulum, left precuneus, leftsupplementary motor area, right cerebellum, left postcentral lobe.There(were) (no) significant correlations between blood ammonia levels of MHEpatients and FA or MD values derived from GM and WM.Along with thatwe found no significant correlations between NP test scores of MHEpatients and FA or MD values (all P ＜ 0.01). 　　Conclusion: DTI was useful to detect the structural abnormalities ofthe brain, which may be implicated in the neurological disorders of MHE. Significant increased MD and decreased FA values in patients with MHEsuggested the increased brain interstitial water leading to low gradecerebral edema and macroscopic abnormalities leading to microstructuralintegrity damage which can be pathological feature of MHE.