Perform Registration of GQI Data

[Yijie Li (一生破晓)]

Hello Dr. Yeh,

I downloaded the hcp-ya GQI files from the Fiber Data Hub and noticed that they are not in MNI space. I would like to linearly register the tractography computed from these GQI files into MNI space, so that all generated tractography results are in a common space (while preserving local details; therefore, I cannot use the mni_track option in the trk action).

So far, I have tried the following approaches:

1. I extracted FA from the GQI file and performed linear registration between the FA map and the MNI FA template using "dsi_studio --action=reg reg_type=0". However, this method fails to save a mapping file. When I try to include the GQI file using the "--s2t" option, DSI Studio reports a dimension mismatch error.

2. I then tried "reg_type=1" with "skip_nonlinear=1". This time, a mapping file is generated successfully, but the mapping is not correctly applied to the GQI file, which remained in the original space.

Given this, I would like to know what the recommended workflow is for performing linear registration of GQI data to MNI space. Specifically, how can I correctly apply a linear transform to the GQI file?

Thank you very much for your time and guidance.

Best regards,

Yijie