Resolving axon fiber crossings at clinical b-values: an evaluation study

Area of Science:

• Neuroimaging
• Biomedical Engineering
• Computational Neuroscience

Background:

• Diffusion tensor imaging (DTI) is standard for mapping brain white matter tracts.
• DTI struggles with complex fiber architectures like crossings and bifurcations.
• High angular resolution diffusion imaging (HARDI) methods improve fiber tract reconstruction.

Purpose of the Study:

• To evaluate multifiber tractography algorithms under clinically relevant, low b-value diffusion MRI conditions.
• To compare the performance of various methods for resolving complex intravoxel fiber architecture.
• To identify the most suitable methods for clinical tractography applications.

Main Methods:

• Compared QBall, spherical deconvolution, persistent angular structure, stick and ball, diffusion basis functions, and analytical QBall.
• Assessed performance using synthetic and in vivo data under low b-value (1000 s/mm²) and limited orientations (30-60).
• Evaluated accuracy in estimating fiber number, signal contribution, and orientation error.

Main Results:

• Not all tested multifiber methods are feasible for clinical diffusion MRI datasets.
• Two methods were found unsuitable for the tested clinical data.
• Identified specific methods excelling in estimating the number of diffusion peaks and diffusion orientation per voxel.

Conclusions:

• A proposed comparison framework effectively evaluates multifiber algorithms in realistic medical settings.
• Results guide clinicians and researchers in selecting appropriate multifiber methods for tractography.
• The study highlights the importance of method selection for accurate brain white matter reconstruction.