Dear CAT experts,
I am running longitudinal preprocessing with CAT12, with three structural MRI runs per participant. After running it, I find that for one participant, in their baseline scan, the volume of CSF is increased, and gray matter is decreased compared to the second and third run. CSF is higher by 10-25 ml, and GM is lower by 20-30ml. White matter, and total intracranial volume are the same across all 3 runs. When visualizing the preprocessed scans in native space, the gray matter volume differences are diffusely spread over many areas. QC is unremarkable. Is this possibly an issue with tissue segmentations? If so, any recommendations for adjusting the longitudinal preprocessing, or other settings to reconcile this inconsistency?
Many thanks in advance,
Joshua McCall
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