 |
 |
Dear SPMers, We've been trying to undrestand to what extent the resolution of the prior probability maps affects the outcome of the segmentation. We performed 2 segmentations on the same brain using the VBM5 toolbox (by Christian Gaser) and a pediatric prior probability maps (courtesy of Cincinnati Children's Hospital Medical Center) at 1x1x1mm resolution, then with the same prior maps at 2x2x2mm (created out of the first one using spm_reslice). We got rather significant differences in the segmentation results, a sample of those results is attached to this post. What we don't understand is the following : Since the prior maps are very smooth, how can changing the resolution of the prior maps influence that much? We couldn't even tell the difference between the 2 prior maps. Any explaination? Thanks in advance, Eric Pierre Case Western Reserve University, Case Center for Imaging Research, Cleveland, Ohio.