A Combination Of Diffusion Tensor Imaging And Magnetic Resonance Spectroscopy Study The Correlation Between Posterior Cingulate Cortex Injury And Cognitive Dysfunction In Type 2 Diabetic Patients

Objective: By combining diffusion tensor imaging(DTI)and proton magnetic resonance spectroscopy(~1H-MRS)to explore the brain metabolism abnormalities and white matter structure changes of the posterior cingulate cortex(PCC)in Type 2Diabetic Patients(T2DM).And to find out the possible mechanism,the relationship with cognitive dysfunction,and also the clinical significance of PCC changes in patients with T2 DM.Materials and Methods: Forty-three patients diagnosed as T2 DM were recruited from Affiliated Zhongshan Hospital of Dalian University from April 2016 to January2017.Ages ranges from 45 to 70 years old(average age: 60.53±5.56 years old),there were 21cases(8 male,13 female)T2DM patients with cognitive dysfunction,22cases(14 male,8 female)T2DM patients without cognitive dysfunction,and 23cases(8 male,15 female)of age-,sex-,and education-matched healthy control subjects.The study was approved by the Committee on Medical Ethnics,written informed consent was obtained for all the participants.All subjects accepted~1H-MRS of PCC and DTI scan on a 3.0 T MRI machine.The contents of metabolites included NAA,Cr,Cho,Glu+Gln,PCr were recorded.PANDA software was used to analyze DTI data,and the whole brain FA and MD value,and the FA and MD value of PCC which matched with shape and size of the MRS were also recorded.Statistical analysis using SPSS 21.0,P< 0.05 was considered as statistically significant.Results:1.There were significant differences of mI/Cr(P <0.001),Glx/Cr(P =0.001)on PCC in T2DM+CD patients,T2 DM patients and healthy controls.Multiple comparisons showed significant differences of mI/Cr(P <0.05)in T2DM+CD group and T2 DM group,T2DM+CD group and HC group,T2 DM group and HC group respectively.The differences of Glx/Cr were existed between T2DM+CD group and T2 DM group,T2DM+CD group and HC group(P < 0.05).The difference of Cr+PCr was only existed between T2DM+CD group and HC group(P=0.017).2.The Glx/Cr was significantly positive correlated with the score of Mo CA(r=0.591,P=0.004),Cr+PCr was positively related with AVLT20min(r=0.483,P=0.027).Other MRS metabolite indexs of PCC were not correlated with clinical variables and cognitive performance.3.There were significant differences of FA,MD value of whole brain and PCC in T2DM+CD patients,T2 DM patients and healthy controls(P < 0.05).Multiple comparisons showed significant differences of FA,MD values of the whole brain and MD value of PCC in T2DM+CD group and T2 DM group,T2DM+CD group and HC group respectively(P<0.05)..The differences of FA value on PCC could be found between T2DM+CD group and T2 DM group,T2DM+CD group and HC group and T2 DM and HC group(P<0.05).4.The FA value of T2DM+CD patients in the PCC area was significantly positive correlated with the score of Mo CA(r=0.572,P=0.007).The FA value was significant negatively correlated with Glx/Cr(r=-0.471,P=0.031).Conclusion:1.Higher MD and mI/Cr value and /or lower FA and Glx/Cr value on PCC is sensitive for brain damage in T2 DM,it can also reflect the progression of brain damage in T2 DM.And they can reflect the brain damage in the early stage.Changes of Cr+PCr can significantly reflect the occurrence of brain damage of T2 DM.2.The changes of FA,MD,Glx/Cr and mI/Cr value in PCC can reflect the imaging findings of early cognitive impairment in T2 DM from two different MRI modes.According to the results of this study,it is suggested that the cause of cognitive impairment in T2 DM patients may be related to PCC neuronal metabolic disorders and cortical,subcortical track loss of white matter fiber bundle damage.