Voxel-Based Morphometry

Voxel-wise parametric statistical tests are performed, which compare the smoothed grey-matter images from the groups using statistical parametric mapping, and corrections for multiple comparisons are generally made using the theory of random fields.

Abstract

At its simplest, voxel-based morphometry (VBM) involves a voxel-wise comparison of regional grey-matter ‘density’ between two groups of subjects. The procedure is relatively straightforward, and involves spatially normalizing and segmenting high-resolution magnetic resonance (MR) images into the same stereotaxic space. These grey-matter segments are then smoothed to a spatial scale at which differences are expressed (usually about 12 mm). Voxel-wise parametric statistical tests are performed, which compare the smoothed grey-matter images from the groups using statistical parametric mapping. Corrections for multiple comparisons are generally made using the theory of random fields.