Dear FreeSurfer team,

I'm currently doing a structural FS analysis with 50 Multiple Sclerosis (MS) patients and 25 Healthy Controls (HC). FLAIR-lesions were drawn onto the aseg.mgz as White Matter Hypointensities (=77). I've finished the analysis, but have some questions regarding my results.

Results:

	HC (n=25)	MS (n=50)	p-value
Mean TIV (SD) [ml]	1594.9 (154.7)	1559.5 (140.1)	> 0.05
Mean WMV (SD) [ml]	503.6 (57.3)	485.2 (59.5)	> 0.05
Mean GMV (SD) [ml]	657.2 (69.9)	635.1 (47.9)	> 0.05
Mean WMHV (SD) [ml]	1.12 (0.4)	5.97 (5.7)	0.0000677

1) Does these results look correct? WMV < GMV?

2) What is the difference between WMV+GMV and TIV? CSF? Ventricles?

3) I find no atrophy in the MS patients; are there reported any problems with FS and MS patients?

4) What is White Matter Hypointensities comprised of in HC?

Best, Silas