Assessment Of Brain Iron Deposition In Type 2 Diabetic Patients With Cognitive Impairment:A Susceptibility Weighted Imaging Study

Objective: Using proton magnetic resonance Susceptibility Weighted Imaging to explore abnormalities of brain iron deposition in Type 2 Diabetic Patients along with the disease progression and the correlation of altered cognitive tests and laboratory indexes.To discuss possible pathological mechanism of brain damage by T2 DM.Methods: 19 T2 DM patients with cognitive dysfunction and 23 T2 DM patients treated in Affiliated Zhongshan Hospital of Dalian University and 30 health controls were included in this study from March 2015 to January 2016. All participants were right-handed and none less than 6 years education.Exclusion criteria of all participants included a history of alcohol or drug abuse,brain infarction or tumor, severe cerebral white matter lesions(ARWMC score greater than1), neurological and psychiatric disease, unable to cooperate with exam,participants who had contraindica tions of MR scan. T2DM+CD and T2 DM patients treated with insulin sensitizing drugs such as thiazolidinediones were excluded. T2 DM patients who had a history of hypoglycemic episode were also excluded. Healthy controls were excluded if they had abnormal glucose metabolism or cognitive dysfunction.General information medical history and medication were recorded. All participants were accepted cognitive tests such as Mo CA, collected their laboratorial indexes such as fasting plasma glucose. All participants were accepted clinical routine MRI scans and SWI scans. Using hands pained 16 ROIS(bilateral red nucleus, substantia nigra, dentate nucleus, globus,pallidus, putamen, thalamus, caudate nucleus, frontal white matter) on the corrected phase maps and measured the phasse shifts which were converted into phase using the formula provided by Image J software and using SPSS statistical analysis software.Single factor analysis of variance were used to compare differences of brain iron deposition between three groups, LSD-t test were used for multiple comparisons.Pearson and Spearman correlation analysis were used for the correlation between brain iron metabolism, cognitive tests scores and laboratory tests values. P values less than 0.05 were considered to be statistically significant.Results:1 The difference iwas existed in biochemical indexes and cognition evaluation among three groups in this study of which the difference of GLU between T2DM+CD group and HC group, T2 DM group and HC group and the difference of HDL and C-peptide between T2DM+CD group and T2 DM group had statistical significance(P<0.05).The difference of Mo CA total score and CDT, VFT, AVLT, AVLT-5min and AVLT-20 min scores had statistical significance(P<0.05) among three groups.2 The brain iron deposition in subjects among three groups in this study was different.Multiple comparisons showed that the difference of iron deposition in right pallidum and right substantia nigra had statistical significance(P<0.05) between two groups while the iron deposition in the rest brain areas had no statistical significance P>0.05)among three groups.3 The brain iron deposition of right pallidum in T2 DM patients is negatively correlated(r=-0.364, P=0.018) to Mo CA while the brain iron deposition of right substantia nigra was negatively and positively correlated to(r=-0.679, 0.607; P=0.001,0.036) Mo CA and TMT-B,respectively.4 The brain iron deposition content of right pallidum in T2 DM patients was significantly negatively correlated(r=-0.502, P=0.008) to C-peptide while the brain iron deposition content of right substantia nigra was significantly negatively correlated(r=-0.381,-0.487; P=0.045, 0.010) to HDL and C-peptide.Conclusion:1 Susceptibility weighted imaging(SWI) had a high specificity of magnetic sensitive material resolution. It can be used in T2 DM patients for quantitative detection of deep gray matter nuclei iron deposits.2 T2 DM patients with increases of gray matter nuclei iron deposits had some correlations with conditions and cognitive impairment. SWI brain iron determination contributes to evaluation and prediction of changes of patient’s cognitive function.3 The brain iron deposition of right pallidum and substantia nigra in T2 DM patients was more distinct. It may be a target position more sensitive to brain injuries, as well as hading some correlations with corresponding clinical indexes and biochemical indexes.