Q: Hi, I need to be able to obtain the mean signal intensity of an ROI in a brain MR image. I thought of using Display to select the ROI, then save the selection as .mnc, then running volume_stats on the volume with a mask of the ROI. However, two problems are associated with that: When running volume_stats on the mask alone, I get dimensions of the mask that are different than when running the mask on top of the volume (e.g. The mask has 9 voxels, but when I run volume_stats on the volume and mask, the # of voxels is now 32!!!), my other problem is that I always get the error: WARNING: Dimensions of RR_ROI_2.mnc do not match those of 0.mnc. Using world coordinates. What does this imply for my measurements?

Using mincstats will not work. I just get the error: Files ROI.mnc and volume.mnc have different sizes of dimensions.

What am I doing wrong? Is there a simpler way of obtaining signal measurement for an ROI?

Thanks,
http://www.bic.mni.mcgill.ca/pipermail/minc-users/2008-April/001953.html

A: When you save your labels in Display there is an option to “Crop Save Lbls” which is set to ON by default. If you set this to OFF, then your ROI file will have the same dimensions as your volume and mincstats won’t complain.

(T)File → (1)Crop Save lbls:Off → (W)Save Labels .mnc