Mark, Tosa:

a) Didn't look like anyone replied on the subject of mris_reverse. FWIW, the mri_convert program that Tosa mentioned operates on the volume, not the surface.

b) mris_reverse multiplies by -1 the "R" coordinate of each RAS vertex, and also re-orders the triples composing each triangle (to preserve sense of inside and outside).

However, the result may no longer register properly with your MRI volume, because the origin of coordinate system is not in the middle of the volume, it's in the middle of voxel 128 (counting from zero).

Hence the mris_reverse-ed surface is off by one voxel.

I ended up writing my own utility to replace mris_reverse and preserve registration, but unfortunately it's not in distributable shape, otherwise I'd offer it. (I'll be getting back to it in the next few weeks, at which point it may get tidied up... so if interested and a wait is OK, let me know).

Graham

------------------------------------------ Mark A. Pinsk wrote:

Hello,

we are desperately in search of a way to flip our freesurfered data. There was a post a while back referring to mris_reverse but it doesn't seem to be included in the current distribution. any help would be greatly appreciated !

thanks mark

Tosa replied: For those freesurfer CORONAL volume,

mri_convert -iid 1 0 0 -ijd 0 0 -1 -ikd 0 1 0 orig flipped

(fake the R direction to be the L direction).

Tosa

--------------------------------------------------- Graham Wideman Author of: Visio 2003 Developer's Survival Pack Microsoft MVP for Visio Resources for programmable diagramming at: http://www.diagramantics.com http://www.wideman-one.com