Abstract #2099

Shieh M, Henry R, Pelletier D, Garrison K, Okuda D

Voxel-based morphometry (VBM) is an unbiased method of comparing local concentrations and volumes of brain tissue across images of the brain. VBM analysis has been slow to be applied to multiple sclerosis patients due to lesions that could provoke distortions during spatial normalization and the validity of lesion masking techniques to correct for this problem has not been explored. CIS patients have relatively few lesions and therefore are the best candidates for investigating this technique. Lesions were masked in 32 CIS patients using a modified version of the method outlined in Brett et al. and statistically compared to 61 control subjects using SPM. CIS patients showed significant volume decreases in the thalamic regions, while similar results were obtained with much lower significance without lesion masking.