Dear Doug,
Thank you again for this email. Do you think it is possible to use this method for ASL images as well? If so, how would you change the options?
Best wishes,
Salil Soman, MD, MS
On Sat, May 25, 2013 at 11:51 AM, Douglas Greve greve@nmr.mgh.harvard.edu wrote:
On 5/25/13 1:39 PM, Salil Soman wrote:
Thank you Doug.
Just so I am clear - is the anatomical the nifti T1.mgz or is it a different file. From your email I gather should do the following:
*1) Use bbregister to register the lowb image to the anatomical. This creates a registration matrix.*
bbregister -s SUBJECTNAME --mov lowb.nii --initfsl --reg register.dat
That is right, but add --t2 (since it is t2 weighted).
*2) Use mri_vol2vol and the registration to map the ADC map to the anatomical*
mri_vol2vol --mov lowb.nii --targ $vol --inv --interp nearest --o $vol2diff --reg $outdir/register.dat --no-save-reg
Use the ADC as the moveable (not lowb, but use the lowb for bbregister). The target volume should be the T1.mgz (or any conformed volume). The output will be the adc in the anatomical space (not sure why you call it vol2diff).
*3) use mri_segstats to extract the values*
*mri_segstats* --seg $SUBJECTS_DIR/SUBJECTNAME/mri/wmparc.mgz --ctab $FREESURFER_HOME/FreeSurferColorLUT.txt --i lowb.nii --sum fa.stats
The input would be the adc volume mapped the anatomical space. I would use WMParcStatsLUT.txt or else you'll get a billion different areas not represented in wmparc. You may also want to add "--seg-erode 1" to erode the segmentations by a voxel. This helps to prevent partial voluming.
doug
Where lowb.nii is the other MRI tissue sequence I am analyzing (e.g. ADC), $vol2diff is the output image of the registration, and fa.stats will be my output stats table?
I suspect there is part of the syntax for these tools I do not understand. Also, what input would $vol be?
Best wishes,
Sal
On Sat, May 25, 2013 at 10:06 AM, Douglas Greve <greve@nmr.mgh.harvard.edu
wrote:
Hi Sal, yes you can. Use bbregister to register the lowb image to the anatomical. This creates a registration matrix. Use mri_vol2vol and the registration to map the ADC map to the anatomical, then use mri_segstats to extract the values doug
ps. Please post questions to the FS list instead of us directly so that others can benefit and it gets archived. thanks!
On 5/25/13 1:03 PM, Salil Soman wrote:
Dear Dr. Greve,
Is it possible to register a nonstructural MR sequences (e.g. an ADC map) with the aseg.mgz file (or aparc+aseg.mgz file, etc) and then, using the segmentation from the aseg (or aparc+aseg) file to output a mean ADC value for each anatomic area segmented?
Thank you for your time and consideration.
Best wishes,
Sal
Salil Soman, MD, MS
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