14800-DvRappard

131 Diffusion tensor imaging in metachromatic leukodystrophy 8 Figure 2. Mean values for FA, MD, AD and RD in NAWM, corpus callosum, pyramidal tracts and thalamus for control subjects (blue), eligible (green) and non-eligible (pink) patients. Error bars indicate standard deviations. Significant differences between groups are indicated with square brackets and a single asterisk (post-hoc Dunnett’s T3, p<0.05). In the selected ROIs (see Fig. 2), FA was decreased for both patient groups compared to controls in NAWM, corpus callosum and pyramidal tracts. Differences were most pronounced between controls and HCT-non-eligible patients. The relative and absolute decrease in FAwas largest in corpus callosum. Inpatients, FA in abnormalWMwas smaller than in NAWM, and lower in HCT-non-eligible patients than in eligible patients (not shown). Although the TBSS analysis showed group differences in FA in the skeletonized thalamus, there were no FA differences in the thalamus based on a ROI analysis. Following the TBSS findings, MD and RD were increased in both patient groups in NAWM, corpus callosum, pyramidal tracts and thalamus, and differences were most pronounced between controls and non-eligible patients. Differences in RD were larger than differences in MD, again with the corpus callosum showing most prominent differences between groups. MD and RD within abnormal WM were higher than in NAWM, but did not differ between patient groups (not shown).