TBSS++: A novel computational method for Tract-Based Spatial Statistics
Davood Karimi Hamza Kebiri Ali Gholipour
Diffusion-weighted magnetic resonance imaging (dMRI) is widely used to assess
the brain white matter. One of the most common computations in dMRI involves
cross-subject tract-specific analysis, whereby dMRI-derived biomarkers are
compared between cohorts of subjects. The accuracy and reliability of these
studies hinges on the ability to compare precisely the same white matter tracts
across subjects. This is an intricate and error-prone computation. Existing
computational methods such as Tract-Based Spatial Statistics (TBSS) suffer from
a host of shortcomings and limitations that can seriously undermine the
validity of the results. We present a new computational framework that
overcomes the limitations of existing methods via (i) accurate segmentation of
the tracts, and (ii) precise registration of data from different
subjects/scans. The registration is based on fiber orientation distributions.
To further improve the alignment of cross-subject data, we create detailed
atlases of white matter tracts. These atlases serve as an unbiased reference
space where the data from all subjects is registered for comparison. Extensive
evaluations show that, compared with TBSS, our proposed framework offers
significantly higher reproducibility and robustness to data perturbations. Our
method promises a drastic improvement in accuracy and reproducibility of
cross-subject dMRI studies that are routinely used in neuroscience and medical
research.