Hello,
I am trying to use Xiao Han's ThicknessRepeatability methods for a
longitudinal study. I have successfully completed step one, which is rigid
registration of the pre and post scans, but I am having problems with step
2. This step uses the mris_thickness_diff function to compute the thickness
difference map. I use the following command, as suggested by Xiao Han:
mris_thickness_diff -xform $SUBJECTS_DIR/1001/mri/transforms/1001_to_1001a.lta \
-src_type curv \
-out $SUBJECTS_DIR/1001/surf/lh.thickness_diff.mgh \
-nsmooth 0 \
-abs -S 1001 \
-L $SUBJECTS_DIR/1001/surf/lh_thickness_diff.log \
$SUBJECTS_DIR/1001/surf/lh.white \
$SUBJECTS_DIR/1001/surf/lh.thickness \
$SUBJECTS_DIR/1001a/surf/lh.white \
$SUBJECTS_DIR/1001a/surf/lh.thickness
The function successfully reads the surfaces, but if fails when trying to
apply the LTA xform to align surface 1 to surface 2. The terminal states:
INFO:try to get src info from transform.
ERROR: ComputeDifferenceNew: MHTfindClosestVewrtexNo returned nnindex=-1,
which is invalid
I have experienced this error for multiple subjects and have been unable to
get past it. I am unsure of what the nnindex is and why it is -1. Any help
on this issue would be greatly appreciated. Thanks.
-Scott Beeman