All MRI image pre-processing and analyses will be conducted with the Statistical Parametric Mapping software SPM8. Multivariate analyses will be conducted with the Multivariate Methods (MM) toolbox for SPM8. Comparisons (preoperatively to 3 months postoperatively) of hippocampal volume and the results of voxel-based volumetry of the medio-temporal lobe and lateral association areas of the temporal and parietal lobes will be performed using ROI analysis. The quantitative imaging results will be correlated to the CERAD-Plus total score performance obtained on the same day as the scans. The relationship of changes in volume (if present) with intraoperative depth of anesthesia (BIS) and the administered dose of sevoflurane expressed as age-corrected minimum alveolar concentration (MAC) equivalent multiplied by time of administration will be calculated. The relationship between changes in gray matter volume (if present) determined by voxel-based morphometry (VBM) and peak values (on postoperative day 2) of inflammatory markers (CRP, IL-6, TNF-alpha) will be determined. We will also use multivariate approaches (voxel-wise multivariate analysis (MANOVA) and classification/prediction procedure) on multi-parameter MRI data in order to build optimal composite predictors of patients' neuropsychological outcomes. In whole brain analysis, we will use a multiple regression and repeated measures ANOVA whole brain voxel-wise analyses in SPM8 to correlate the estimated modulated gray matter volume with the neuropsychological scores.