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Dear Franz, Christian- Depending on image sequence/quality, if you are having problems removing dura/skull adequaltely using/tweaking SPM/VBM8 toolboxes inhomogeneity correction/regularization parameters, you can try using another program (e.g., FSL- BET, MIPAV- N3 & SPECTRE) that may do a better job. Christian, if one were to do this, would any changes need to be made to VBM8 toolbox processing if beginning with skull-stripped images? Any comments from anyone else on what considerations, if any, when using SPM's New Segment for VBM if beginning with skull-stripped images? HTH- -Julie Julie E. McEntee, MA, CCRP Image Processing Technologist Center for Neuroscience & Regenerative Medicine, NIH/USUHS The Henry M. Jackson Foundation for the Advancement of Military Medicine NIH Clinical Center B1N264B 301-451-1869 [log in to unmask] Department of Psychiatry & Behavioral Sciences Division of Psychiatric Neuroimaging The Johns Hopkins School of Medicine [log in to unmask] On Tue, 16 Nov 2010 14:44:25 +0100, Franz Riederer <[log in to unmask]> wrote: >Dear all, > >I see there is a lot of effort to support people working with structural MRI >analyses, and I am grateful for that. Although I got some inspiration from >the archives of the mailing list, I could not find an answer for the >following problem: >In some rare instances grey matter seems classified as white matter (please >see attachment, blue arrow). In these instances, the dura over the cortex >appears rather bright (lower image). Changing the bias regularisation to >"extremely light" instead of the default "very light" seemed to have a minor >positive effect. > >To my surprise, the Unified Segmentation within SPM8 seemed to be less >sensitive to this artifact. > >I also see that this might be a problem of the sequence we used in this >subject. > >I wonder whether there is a way to optimize post processing. > >Many thanks in advance, > > >Franz >