Quality control for FreeSurfer ROIs (parcellations)

[effigies]

One use of FreeSurfer parcellations is to identify voxel seeds for tractography. A desired QC feature is to assess whether subjects had normal-sized ROIs, and to alert on small/missing ROIs.

Currently unclear what the best metrics are here, though building per-ROI distributions of sizes should be possible through OpenFMRI datasets. Pre-computation would be limited to specific atlases/parcellations, however.

Reported by Josiah L from the Knutson Lab.