Dear FreeSurfer experts,
I computed distances on the cortex surface of fsaverage using mris_pmake. The exact syntax of the distance computation was:
mris_pmake --subject fsaverage --hemi lh/rh --surface0 smoothwm --curv0 sulc --curv1 sulc --mpmOverlay euclidean --mpmProg pathFind --mpmArgs startVertex:XXXXX,endVertex:XXXXX .
Subsequently, the euclidean distance was computed using the MNI coordinates displayed by tksurfer if the startVertex and the stopVertex are selected:
distance_euc = sqrt[(startMNI_x-stopMNI_x)^2+(startMNI_y-stopMNI_y)^2+(startMNI_z-stopMNI_z)^2] .
The in-surface distance must be larger or equal to the euclidean distance. However, in ~50% of the cases investigated the opposite is computed. Typical distances calculated are in the range of 7 mm. Do you have an explanation for this outcome and a possible solution? How can it be corrected? I am using FreeSurfer 5.3 and did not encounter any other problems in data evaluation. Any help us highly appreciated!
Sincerely yours
pfannmoe
Please remove this mail. This problem was already solved.
On Tue, 7 Oct 2014 16:55:16 +0200 pfannmoelj@uni-greifswald.de wrote:
Dear FreeSurfer experts,
I computed distances on the cortex surface of fsaverage using mris_pmake. The exact syntax of the distance computation was:
mris_pmake --subject fsaverage --hemi lh/rh --surface0 smoothwm --curv0 sulc --curv1 sulc --mpmOverlay euclidean --mpmProg pathFind --mpmArgs startVertex:XXXXX,endVertex:XXXXX .
Subsequently, the euclidean distance was computed using the MNI coordinates displayed by tksurfer if the startVertex and the stopVertex are selected:
distance_euc = sqrt[(startMNI_x-stopMNI_x)^2+(startMNI_y-stopMNI_y)^2+(startMNI_z-stopMNI_z)^2] .
The in-surface distance must be larger or equal to the euclidean distance. However, in ~50% of the cases investigated the opposite is computed. Typical distances calculated are in the range of 7 mm. Do you have an explanation for this outcome and a possible solution? How can it be corrected? I am using FreeSurfer 5.3 and did not encounter any other problems in data evaluation. Any help us highly appreciated!
Sincerely yours
pfannmoe
Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
The information in this e-mail is intended only for the person to whom it is addressed. If you believe this e-mail was sent to you in error and the e-mail contains patient information, please contact the Partners Compliance HelpLine at http://www.partners.org/complianceline . If the e-mail was sent to you in error but does not contain patient information, please contact the sender and properly dispose of the e-mail.
freesurfer@nmr.mgh.harvard.edu
-
pfannmoelj＠uni-greifswald.de