Abstracts

Optimized voxel-based morphometry (VBM) was recently developed to increase the sensitivity of standard VBM in detecting neuroanatomical differences [italic]in vivo[/italic] using structural magnetic resonance images. In this study, we used optimized VBM with and without modulation to assess how hippocampal structural and metabolic abnormalities are correlated in MTLE/HS patients., Optimized VBM of gray matter concentration (GMC) and gray matter volume (GMV) was performed in 20 consecutive MTLE/HS patients (mean age 39.5[plusmn]9.48 years) and 20 sex- and age-matched healthy controls (mean age 39.1[plusmn]7.97 years). Ratios of N-acetyl-aspartate (NAA) to Creatine/Phosphocreatine (Cr) were measured in the same subjects from each hippocampus. First we compared statistical parametric mappings (SPMs) of group-wise regional gray matter differences between the patients and the controls. The mean GMC and mean GMV were subsequently calculated in both the affected and unaffected hippocampi in patients and healthy subjects and these were compared. Finally, the mean GMC, mean GMV, and NAA/Cr were correlated. Correlations between investigated variables and disease duration were also analyzed., 1/ SPM analysis revealed significantly more extensive hippocampal GMV reduction than hippocampal GMC reduction in the patients[apos] affected hippocampus. 2/ Significant decreases in the mean GMC (p[lt]0.001), mean GMV (p[lt]0.001), and NAA/Cr values (p[lt]0.01) were revealed in the affected hippocampi compared to the values within the unaffected hippocampi in both patients and healthy subjects. A significant GMC decrease was also observed in the unaffected hippocampi in the patient group in comparison to the hippocampal GMC values in the control group (p=0.0078). 3/ Pearson[apos]s correlation between GMV and NAA/Cr (but not between GMC and NAA/Cr) was significant for the affected hippocampus (p=0.045; r=0.45). No correlation was found between GMC, GMV, or NAA/Cr and disease duration., Structural and metabolic abnormalities as detected by optimized GMV and ¹H MRS are significantly correlated in affected hippocampi in MTLE/HS patients.,