Clinical Study Of MR DTI In The Diagnosis Of Amnestic Mild Cognitive Impairment,Alzheimer's Disease And The Evaluation Of Cognitive Function

Objective: Using diffusion tensor imaging(DTI)to examine the microstructural changes of white matter fibers in patients with Alzheimer's disease(AD)and amnestic mild cognitive impairment(a MCI),to evaluate the degree of damage in white matter and to explore the contributions of DTI to the diagnosis of AD and a MCI.Methods: Fifteen cases in AD and a MCI group,respectively,and 15 age-and gender-matched healthy controls(NC group)were collected from the First Affiliated Hospital of Shihezi University during Oct.2017 to Aug.2018.The original images were obtained using DTI technology and transferred to the GE MR ADW 4.6 workstation for signal processing.The fractional anisotropy(FA)and average diffusion coefficient(ADC)in region of interest(ROI)were measured by Functool software and the data were statistically analyzed to compare the difference of microstructures of white matter among these groups.Results: 1.Among these three groups,the score of neuropsychological scale,including the Montreal Cognitive Assessment(Mo CA)and the Mini-Mental State Examination(MMSE),was significantly different(P < 0.05),but there was no significant difference in the score of Hachinski Ischemic Score(HIS)and Self-Rating Depression Scale(SDS)(P > 0.05).2.Compared with NC group,the FA values in AD patients showed significant increase(P < 0.05)in bilateral temporal lobe,right occipital lobe,bilateral internal capsule forelimbs,posterior limb of internal capsule,corpus callosum genu,callosum splenium,bilateral anterior cingulate gyrus,posterior cingulate gyrus,parietal lobe,frontal lobe and other areas,but not the left occipital lobe(P > 0.05).3.Compared with NC group,the ADC values in the bilateral temporal lobes,left inner capsule posterior limbs,corpus callosum genu,callosum splenium,bilateral posterior cingulate gyrus,frontal lobe and other areas significantly increased(P < 0.05)in AD group,but no difference in bilateral anterior cingulate gyrus(P < 0.05).4.In a MCI group,the FA values in the bilateral temporal lobe,the anterior limb of internal capsule and posterior limb of internal capsule,corpus callosum genu,callosum splenium,left anterior cingulate gyrus,bilateral posterior cingulate gyrus,right parietal lobe,frontal lobe and other areas increased significantly compared with NC group(P < 0.05),but not in the bilateral occipital lobe and right anterior cingulate gyrus(P > 0.05).5.The ADC values in a MCI group increased significantly(P < 0.05)in the bilateral temporal lobe corpus callosum,corpus callosum genu,callosum splenium,bilateral posterior cingulate gyrus and frontal lobe compared with the NC group,but no significant difference in bilateral internal capsule of occipital lobe,anterior limb,internal capsule,posterior limb,anterior cingulate gyrus and parietal lobe.6.Compared with a MCI group,the FA values in bilateral temporal lobe,anterior and posterior limb of internal capsule,corpus callosum genu,callosum splenium,bilateral anterior cingulate gyrus,posterior cingulate gyrus,parietal and frontal lobe showed significant increase in AD group(P < 0.05),but no significant difference in bilateral occipital lobe.7.The FA values in AD group values showed significant increase(P < 0.05)in bilateral temporal posterior limb of left internal capsule lobe,corpus callosum genu,callosum splenium,bilateral posterior cingulate gyrus,parietal lobe and right frontal lobe compared with a MCI group,but no significant difference in the left frontal lobe,bilateral occipital lobe,anterior extremity of bilateral internal capsule and right posterior extremity of internal capsule.8.AD group had only right temporal lobe and directional force(r=-0.792;P < 0.05)was significantly correlated.Conclusions:(1)There was selective damage in the microstructures of white matter in a MCI and AD patients,and the damage in AD patients was more extensive,indicating that DTI can be an index for the distinctive diagnosis of a MCI and AD.(2)Magnetic resonance DTI can detect the changes of ADC and FA values in different brain regions of AD and a MCI patients.The damage was found in higher functional areas(i.e.temporal lobe,parietal lobe and frontal lobe),while no obvious damage in primary functional areas(i.e.occipital lobe).