ABSTRACT
and indexes of the ROI which had significant difference between the groups. Results In the white matter regions, MD, D∥and D⊥in many regions of AD group were increased significantly than the control group, and the differences were statistically significant. MD and D ⊥ showed more abnormalities, including the SCC, PCB, and FWM. Meanwhile, MK, K∥and K⊥in many regions of AD were decreased, and the differences were statistically significant. K ⊥ showed more abnormalities, including the SCC, FWM and TWM. In the gray matter regions, MD, D∥and D⊥of hippocampal of the AD group were all increased than the control group. However, it showed that MK and K⊥of the thalamus in AD group were 0.99 ± 0.10, 1.00 ± 0.11, respectively, and both increased than the control group (the value of MK and K⊥were 0.90±0.06, 0.90±0.07, respectively), and the differences were statistically significant (t values was 3.31, 3.57 respectively, and both P values were<0.01). The indexes of different ROI had correlations with the MMSE scores. There were more regions in kurtosis indexes correlated with the MMSE scores than the diffusion indexes. The strongest correlation among the analyses was MK of the SCC (r=0.73, P<0.05). Conclusions This study based on DKI found the complex alterations aroused by microstructural changes were not only in the white matter but also the gray matter of the AD patients, especially the increased kurtosis of the thalamus, and this suggested that the microstructural complexity of it was increased. Moreover, it also suggested that indexes of DKI had varied sensitivity in detecting different diffusion alterations.