Hi Surfers, As you know, there are multiple ways to measure contrast to noise ration (CNR). I am trying to understand how is cnr.nii generated as an output from mri_glmfit command. I also noticed that, cnr.nii values are mostly NaN when I have one subject only. I am wondering why it is not the same as cnr.nii generated by selxavg3-sess for the same subject.
Regards
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Shahin Nasr
PhD in Cognitive Neuroscience Martinos Imaging Center, MGH Harvard Medical School Bldg 149, 13th street, Charlestown, MA 02129
In mri_glmfit, this is just the contrast value (gamma) divided by the residual stddev (rstd), and something similar for the selxavg3-sess. In mri_glmfit, the residual is the residual of the group model; in selxavg it is the residual from the timer series modeling, so they are very different
On 12/21/2017 12:17 PM, shahin@nmr.mgh.harvard.edu wrote:
Hi Surfers, As you know, there are multiple ways to measure contrast to noise ration (CNR). I am trying to understand how is cnr.nii generated as an output from mri_glmfit command. I also noticed that, cnr.nii values are mostly NaN when I have one subject only. I am wondering why it is not the same as cnr.nii generated by selxavg3-sess for the same subject.
Regards
Shahin Nasr
PhD in Cognitive Neuroscience Martinos Imaging Center, MGH Harvard Medical School Bldg 149, 13th street, Charlestown, MA 02129
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