Hi Yuko - You can use the low-b images and compute the SNR of those images inside a mask of the white matter. Because dt_recon computes a registration from the diffusion to the structural data, you can use that registration to map the white matter label from the freesurfer segmentation (aseg) to the diffusion data. Then calculate the mean and standard deviation of the values of the low-b images inside that white matter mask.
Hope this helps, a.y On Mon, 17 Mar 2014, Yuko Yotsumoto wrote:
Hello Freesurfers, I have DTI data for two groups of subjects, and were asked SNR for each group. I did ROI analysis on FA values, therefore, I do not have the averaged DTI data. I am wondering if there is any way to compute SNR from dt_recon output. It doesn't have to be the ROI specific SNR values, I just need SNR for the whole DTI data for each group. Any suggestions will be appreciated! Yuko Yotsumoto --- ------------------------------------------------------------- Yuko Yotsumoto, Ph. D. Associate Professor The University of Tokyo, Department of Life Sciences Bldg #2, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902 Japan phone : (+81)-3-5454-4332 E-mail: cy...@mail.ecc.u-tokyo.ac.jp
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