  The corticospinal tract (CST) is a critically important white matter fiber
tract in the human brain that enables control of voluntary movements of the
body. Diffusion MRI tractography is the only method that enables the study of
the anatomy and variability of the CST pathway in human health. In this work,
we explored the performance of six widely used tractography methods for
reconstructing the CST and its somatotopic organization. We perform experiments
using diffusion MRI data from the Human Connectome Project. Four quantitative
measurements including reconstruction rate, the WM-GM interface coverage,
anatomical distribution of streamlines, and correlation with cortical volumes
to assess the advantages and limitations of each method. Overall, we conclude
that while current tractography methods have made progress toward the
well-known challenge of improving the reconstruction of the lateral projections
of the CST, the overall problem of performing a comprehensive CST
reconstruction, including clinically important projections in the lateral (hand
and face area) and medial portions (leg area), remains an important challenge
for diffusion MRI tractography.
