help > Missing data for subject-specific ROIs
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Jan 10, 2022  04:01 AM | Jessica Busler
Missing data for subject-specific ROIs
Hi!

I was trying to load a subject-specific ROIs based on MRS voxel locations but not all the subjects in my CONN project completed the MRS scan. Is there a way to allow missing files for an ROI? It seems nothing will process and that ROI will not show up to use in analyses even if I tell it to only process the subjects in the project that have a file for the ROI.

Would appreciate any help anyone can offer.

Best,
Jessica
Jan 11, 2022  01:01 PM | Alfonso Nieto-Castanon - Boston University
RE: Missing data for subject-specific ROIs
Hi Jessica,

That's a good point/suggestion. Sorry that currently CONN does not directly support missing files when defining subject-specific ROI files (or missing-data for specific ROIs). As a work-around I would probably suggest to enter in Setup.ROIs any arbitrary mask for those subjects with missing MRS scans, and then explicitly remove those subjects from any second-level analysis that uses these ROIs data.

For reference, you can remove subjects from a particular second-level analysis for example by first defining a second-level covariate named "ValidSubjects" containing 0 values for valid subjects and NaN values for invalid subjects, and simply adding that covariate to any existing second-level analysis and adding a corresponding 0 value to the between-subjects contrast (e.g. if your original analysis was 'GroupA' 'GroupB' with a contrast [-1 1] to look at two-sample t-test, the new analysis will be 'GroupA' 'GroupB' 'ValidSubjects' with a contrast [-1 1 0] to perform the same two-sample t-test limited only to "valid" subjects)

Hope this helps
Alfonso
Originally posted by Jessica Busler:
Hi!

I was trying to load a subject-specific ROIs based on MRS voxel locations but not all the subjects in my CONN project completed the MRS scan. Is there a way to allow missing files for an ROI? It seems nothing will process and that ROI will not show up to use in analyses even if I tell it to only process the subjects in the project that have a file for the ROI.

Would appreciate any help anyone can offer.

Best,
Jessica
Jan 11, 2022  05:01 PM | Jessica Busler
RE: Missing data for subject-specific ROIs
Thanks Alfonso!  That's super helpful!! I will try this out :)

Best,
Jessica