Clinical application of apparent diffusion coefficient mapping in voxel-based morphometry in the diagnosis of Alzheimer's disease.

AIM: To evaluate the performance of apparent diffusion coefficient (ADC) mapping compared with voxel-based morphometry and to demonstrate the clinical usefulness of ADC mapping in the diagnosis of Alzheimer's disease (AD).

MATERIALS AND METHODS: The study population comprised 31 patients with AD (group A) and 24 patients without dementia (group B) who underwent three-dimensional (3D) T1-weighted imaging (WI) and two-dimensional (2D) echo-planar diffusion-weighted imaging (DWI) at 3 T. The volume and ADC of the regional grey matter (GM) in the bilateral hippocampi, precunei, and the anterior and posterior cingulate gyri were calculated using a voxel-based method for automatic segmentation of brain structures. The significance of intergroup differences in each volume and ADC of all regional GM was tested using analysis of variance (ANOVA) with Bonferroni correction. Intergroup regional GM differences in each volume and ADC were evaluated using statistical parametric mapping (SPM).

RESULTS: In group A, the volumes of the precunei (mean value: group A/B=18.93/21.48 cm(3)) and the anterior cingulate gyri (mean value: group A/B=6.1/7.81 cm(3)) were significantly less than in group B (p<0.05). The ADC in group A was significantly larger than that in group B in the bilateral hippocampi (mean value: group A/B=right 1020.79×10(-6)/877.23×10(-6) mm(2)/s; left 1072.89×10(-6)/900.2×10(-6) mm(2)/s) and posterior cingulate gyri (mean value: group A/B=1006.77×10(-6)/876.88×10(-6) mm(2)/s; p<0.05). SPM showed that the areas of increased ADC were more extensive than the areas of decreased volume in the bilateral hippocampi, precunei, and posterior cingulate gyri in group A, compared with those in group B (p<0.001).

CONCLUSION: Evaluation of ADC mapping can quantify changes in brain water diffusivity and may improve the performance of automatic morphometric diagnosis of AD.