[Study on the white matter neuronal integrity in amnestic mild cognitive impairment based on automating fiber-tract...

Objective: To analyze the pattern of the change in cerebral white matter tract in amnestic mild cognitive impairment (aMCI) patients based on the automating fiber-tract quantification (AFQ). Methods: A total of 20 aMCI patients,9 males,11 females, the mean age was (67±9) years, and 22 patients with naMCI, 8 males,14 females, the mean age was (64±10) years, and 23 normal control subjects, 10 males, 13 females, with a mean age of (65±9) years were enrolled from the Affiliated Drum Tower Hospital of Nanjing University Medical School from January 2018 to March 2019. All of them underwent 3.0 T MRI scan, which include DTI and 3D T(1)WI sequence.Two tract profiles, fractional anisotropy (FA) and mean diffusivity (MD), were extracted to evaluate the white matter integrity at 100 locations along each of 20 fiber tracts based on the AFQ. Results: In a pointwise comparison of FA profiles,the aMCI patients showed FA reduction in the middle part of right corticospinal tract (t=-4.023, P<0.01, FWE corrected) relative to the naMCI patients. There was a positive correlation between the decreased FA value and the auditory verbal learning test score (P=0.039). In a pointwise comparison of MD profiles, the aMCI patients showed extensive MD elevation in the middle part of the left cingulum hippocampus (t=2.408,P=0.037,FWE corrected) relative to the naMCI patients. The aMCI patients showed MD elevation in the posterior part of the left inferior longitudinal fasciculus (t=-2.919, P=0.006, FWE corrected) and the middle part of the left cingulum hippocampus (t=-3.878, P=0.002, FWE corrected) relative to the NC subjects. And the elevated MD in left inferior longitudinal fasciculus showed negative correlation with MoCA (P=0.039) and auditory verbal learning test score (P=0.015). There was also a negative correlation between the elevated MD value in the left cingulum hippocampus and the auditory verbal learning test score (P=0.033). Conclusions: Disruption is found in specific part along the white matter tract in the aMCI group. Furthermore, the pattern of white matter abnormalities is different across neuronal fiber tracts. These findings will have an impact on the further specific study of the white matter tract in aMCI patients.