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Hello all,

I've got a scan with an abnormally high Left-Hippocampus volume (based on the measurement in the aseg.stats file).

Loading aparc+aseg.mgz and brainmask.mgz into freeview confirms that far too much matter has been labelled as Left-Hippocampus. I'd like to replace the extra Left-Hippocampus with Left-Cerebral-White-Matter. Is it sufficient to simply draw Left-Cerebral-White-Matter directly on top of the Left-Hippocampus voxels I want to replace (using the Voxel edit tool)?

I also need the Left-Hippocampus volume measurement in the aseg.stats file to be updated after my edits. Presumably I need to rerun recon-all from a certain point to achieve this, but I'm not sure from which point.

Also, is editing aparc+aseg.mgz is the correct way to go about this? There are many other files (such as lh.hippoSfLabels-T1.v10.mgz) that also visualize the hippocampus and also show the excessive left hippocampus labeling, so maybe I need to edit those instead. I suppose this question boils down to which file aseg.stats bases its measurements off of.

Summary: -To erase voxels of one structure, is it proper to simply overwrite it with voxels of whatever other structure I want in its place? -Which file should I edit if I want the volume measurements in aseg.stats to be updated? -After I make my edit, from what point should I rerun recon-all to have aseg.stats updated accordingly?

Any help is greatly appreciated.