dki-questions > RE: bvecs extracted from bmatrix or grad table
Nov 21, 2016  07:11 PM | Ehsan Misaghi - University of Alberta
RE: bvecs extracted from bmatrix or grad table
Hi Emilie,

The NIFTI file I got from the scanner is accompanied by two txt files. One of them includes the scanning parameters such as the echo time, resolution, etc. This file also includes the gradient table (the file I've attached to this post contains the gradient table part of that file. The bvecs_gtable.bvec file I had attached to the first post was a reorganization of this file into the conventional bvecs format). The other file is a bmatrix for use with the ExploreDTI software. I have used that bmatrix with ExploreDTI before and the directions look fine with a permutation of the gradient directions, but unfortunately, ExploreDTI is not capable of doing DKI-based tractography, hence the need to use DKE. Normally, what we did with ExploreDTI was that we converted the bvecs and bvals files into the bmatrix file before processing and used the bmatrix with the NIFTI file. However, since I don't have the original bvecs/bvals for this dataset, I used MATLAB to extract the bvals and bvecs (the code I used: https://groups.google.com/d/msg/e_dti/8-bk8GKcQ9g/VruykovSBgAJ). The bvecs file for this was attached to the first post as bvecs.bvec. I hope this gives more info as to where these files came from.

Thanks again for your help,
Ehsan
Attachment: grad_table.txt

Threaded View

TitleAuthorDate
Ehsan Misaghi Nov 20, 2016
Emilie McKinnon Nov 21, 2016
Ehsan Misaghi Nov 21, 2016
Emilie McKinnon Nov 21, 2016
RE: bvecs extracted from bmatrix or grad table
Ehsan Misaghi Nov 21, 2016
Emilie McKinnon Nov 21, 2016