Dear Expert,
I have a technical question regarding the processing of DTI data for anatomical consistency.
Assuming I have already obtained the unique 3x3 Diffusion Tensor matrix (D) solved via Least Squares from 64-direction DWI signals. Currently, the standard components (D_xx, D_yy, D_zz are reported relative to the MRI scanner’s laboratory frame, which leads to inconsistent values when a subject’s head orientation varies.
If I have pre-defined a fixed anatomical coordinate system—specifically the unit vectors v_x, v_y, v_z of a known fiber bundle (e.g., projection fibers)—can I directly extract a new set of metrics (D’_xx, D’_yy, D’_zz) using the quadratic form d = v^T .D.v for each respective direction?