Diffusion Spectrum Imaging Identifies Deficits In White Matter Microstructure In Subjects With Type 2 Diabetes Mellitus

Objective: Diffusion spectrum imaging(DSI) of MRI can detect neural fiber tract changes.This study investigated the microstructural abnormalities in specific cerebral white matter tracts of type 2 diabetes using diffusion spectrum imaging(DSI) tractography and its correlations with cognitive functioning and blood biochemical index.Material and methods: 48 subjects from Affiliated Zhongshan Hospital of Dalian University were recruited, with 27 T2 DM patients(60.6±7.6years) and 21 age-, sex-, and education-matched healthy persons(HC,56.1±7.8years).All subjects underwent a battery of neuropsychological tests including montreal cognitive assessment( Mo CA)、Clock Drawing Test(CDT) and verbal fluency test(VFT) to access their executive, memory and language functions.To collect all T2 DM patients’ blood biochemical indexes including fasting blood glucose, glycated hemoglobin(Hb Alc), C-peptide,total cholesterol(CHO), triglycerides, high-density lipoprotein(HDL) and low density lipoprotein(LDL).We used a Siemens 3.0-tesla Magnetom Verio MRI scanner to obtain T1- and T2-FLAIR weighted images for anatomy and used a pulsed gradient twice refocused spin-echo diffusion echo-planar imaging sequence to acquire DSI. Diffusion spectrum imaging measures, namily generalfractional anisotropy(GFA) were compared between groups by used of two sample t test and related to cognitive performance by used of Pearson correlation analysis.Result: GFA value was significantly decreased in left uncinate fasciculus(0.789±0.007),right uncinate fasciculus(0.795±0.006)and right superior cingulum bundle(0.809±0.01) in T2 DM patients compared with control subjects(P<0.05). The left uncinate fasciculus(t=-2.915, P=0.005) and right superior cingulum bundle(t=-2.604, P=0.012) was statistically significant.The neurocognitive score including Mo CA(22+3.45), CDT(2.74+0.66),VFT(44.44+7.54) of T2 DM patients were lower than that of healthy controls(Mo CA was 24.76+1.76,CDT was 3.29+0.56,VFT was 48.81+8.54).Mo CA( t=-3.339, P=0.002) and CDT(t=-3.039,P=0.004)score was statistically significant.GFA value of the left superior cingulum bundle was negetive associated with VFT test(r=-0.475,p=0.012) and GFA value of the right superior cingulum bundle was negative associated with blood CHO lever(r=-0.458,p=0.016).Conclusions: DSI tractography demonstrated individuals with type 2 diabetes showed microstructural abnormalities in white matter pathways such as Uncinate fasciculus and Superior cingulum bundle. These white matter alterations could be one of the causes of memory and emotional processing impairment in T2 DM.The cognitive score and blood lipid level may predict the pathological changes of cerebral microstructure and assess the disease condition to a certain extent.