Stitching/combining two DTI scans

Hi,

I’m trying to combine two DTI scans acquired sequentially from the same participant. The main aim of doing this is to get a larger FOV and perform fibre tracking simply on the combined image. These two scans overlap by ~ 2-3 cm, and are acquired with different orientations and b vectors

Scan 1:
image

Scan 2:
image

I’m having trouble finding commands in MRtrix suitable for this purpose. My current workflow still relies on a combination of MRtrix and Matlab, which typically follows the procedures:

  1. Regrid both DTI scans (denoised) to match the dimension of mDIXON scan using mrgrid scan1.mif scan1_regrid.mif -template mdixon.mif -fill nan (MRtrix)
  2. Add two scan images (stored as 4d matrix) (MATLAB)
  3. Average image data in the region where they overlap (MATLAB)

However, the combined DTI image is either having two regions with different intensities, or only one of the scans is contained in the combined image while the other one is missing. Also, despite the difference between b vectors of two scans are minor, I’m not sure if this is going to affect the results a lot.

I’m wondering if there is a way to perform such scan combination properly, correcting the intensities of two scans and without bringing errors in b vectors along the way?

Thank you so much in advance!

Yilan

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