3T MR Diffusion Tensor Imaging Studies In Patients With Type 2 Diabetes Mellitus

Objective:Taking advantage of 3T MR diffusion tensor imaging technique to evaluate white matter abnormalities in patients with type 2 diabetes mellitus, through locating various regions of interest on white matters, measuring the main DTI parameters and then analyze the correlation between clinical data and DTI parameters. To examine whether type 2 diabetes mellitus is associated with microstructural abnormalities in specific cerebral regions and analyze the clinical risk factors, in order to help clinicians have an earlier diagnosis, better treatment of the disease and evaluate the prognosis.Methods:25 cases with a clinical diagnosis of both type 2 diabetes mellitus and hypertension,20 cases with type 2 diabetes mellitus only and 20 healthy controls were included in this study. Each subject underwent a 3 Tesla diffusion-tensor MRI scan. Diffusion tensor imaging parameters, including fractional anisotropy(FA), average diffusion coefficient(DCavg) and relative anisotropy (RA) were measured in bilateral white matters of frontal lobe, parietal lobe, occipital lobe, temporal lobe, posterior limb of internal capsule and the genu and splenium of corpus callosum as well as bilateral hippocampus. The measurements were compared between groups and related to duration of the disease, HbAlc values and body mass index. Tractography was performed to reconstruct several white matter tracts.Results:The incidence of lacunar infarct, leukoaraiosis and brain atrophy in T2DM groups was obviously higher than healthy controls. FA and RA of left occipital lobe and DCavg of right frontal lobe white matters in three groups showed significant difference (P<0.05) present with decreased FA and RA and increased DCavg in T2DM groups compared with controls. Compared with controls, the FA and RA of right frontal lobe, left temporal lobe and splenium of corpus callosum in T2DM groups showed decreased tendency while the DCavg showed increased tendency. The three kinds of measures in left frontal lobe, bilateral parietal lobe, genu of corpus callosum, left posterior limb of internal capsule and left hippocampus showed no significant difference. The FA and RA of right occipital lobe, the FA and DCavg of right temporal lobe and the right posterior limb of internal capsule, the DCavg and RA of right hippocampus all showed no significant difference. The FA of left occipital lobe were strongly negatively correlated with the level of glycated hemoglobin A (r=-0.301, P=0.044) and there was no correlation between the FA and the disease duration, body mass index respectively. The DCavg of right frontal lobe has no significant correlation with glycated hemoglobin A、disease duration and body mass index. Diffusion tensor tractography showed the white matter tracts in T2DM group were less compact and with decreased integrity compared with controls, manifested sparseness and cutoff characteristics.Conclusions:Microstructural white matter abnormalities and associations with clinical measurements can be detected with DTI in T2DM patients both sensitively and effectively, and it is of great significance to help us have a better understanding of the white matter circuits in T2DM patients. The white matters of occipital lobe, frontal lobe and temporal lobe were more vulnerable than others. Compared with disease duration and BMI, glycated hemoglobin levels had the greatest negative impact on DTI parameters. Diffusion tensor tractography could show the abnormalities of white matter tracts more vividly.