TY - JOUR T1 - Regional Analysis of the Magnetization Transfer Ratio of the Brain in Mild Alzheimer Disease and Amnestic Mild Cognitive Impairment JF - American Journal of Neuroradiology JO - Am. J. Neuroradiol. SP - 2098 LP - 2104 DO - 10.3174/ajnr.A3568 VL - 34 IS - 11 AU - M. Mascalchi AU - A. Ginestroni AU - V. Bessi AU - N. Toschi AU - S. Padiglioni AU - S. Ciulli AU - C. Tessa AU - M. Giannelli AU - L. Bracco AU - S. Diciotti Y1 - 2013/11/01 UR - http://www.ajnr.org/content/34/11/2098.abstract N2 - BACKGROUND AND PURPOSE: Manually drawn VOI-based analysis shows a decrease in magnetization transfer ratio in the hippocampus of patients with Alzheimer disease. We investigated with whole-brain voxelwise analysis the regional changes of the magnetization transfer ratio in patients with mild Alzheimer disease and patients with amnestic mild cognitive impairment. MATERIALS AND METHODS: Twenty patients with mild Alzheimer disease, 27 patients with amnestic mild cognitive impairment, and 30 healthy elderly control subjects were examined with high-resolution T1WI and 3-mm-thick magnetization transfer images. Whole-brain voxelwise analysis of magnetization transfer ratio maps was performed by use of Statistical Parametric Mapping 8 software and was supplemented by the analysis of the magnetization transfer ratio in FreeSurfer parcellation-derived VOIs. RESULTS: Voxelwise analysis showed 2 clusters of significantly decreased magnetization transfer ratio in the left hippocampus and amygdala and in the left posterior mesial temporal cortex (fusiform gyrus) of patients with Alzheimer disease as compared with control subjects but no difference between patients with amnestic mild cognitive impairment and either patients with Alzheimer disease or control subjects. VOI analysis showed that the magnetization transfer ratio in the hippocampus and amygdala was significantly lower (bilaterally) in patients with Alzheimer disease when compared with control subjects (ANOVA with Bonferroni correction, at P < .05). Mean magnetization transfer ratio values in the hippocampus and amygdala in patients with amnestic mild cognitive impairment were between those of healthy control subjects and those of patients with mild Alzheimer disease. Support vector machine–based classification demonstrated improved classification performance after inclusion of magnetization transfer ratio–related features, especially between patients with Alzheimer disease versus healthy subjects. CONCLUSIONS: Bilateral but asymmetric decrease of magnetization transfer ratio reflecting microstructural changes of the residual GM is present not only in the hippocampus but also in the amygdala in patients with mild Alzheimer disease. ADAlzheimer diseaseAUCarea under the receiver operating characteristic curveDARTELDiffeomorphic Anatomical Registration through Exponentiated Lie AlgebraMCImild cognitive impairmentMTmagnetization transfer ER -