Assessment of Asymmetry in Pyramidal Tract by Using Fiber Tracking

Diffusion Tensor Imaging (DTI) and tractography are able to model fiber architecture within the white matter and become a major component of clinical neuroradiology. The challenge is to answer neuro-anatomic questions by using group studies. In some diseases, the asymmetry between involved tracts is expected to be greater than that in controls. If the quantitative detection of asymmetry is sufficiently sensitive, it will be a good marker of clinically relevant tract-specific abnormalities. In this work, we quantify the range of asymmetry between the right and left pyramidal tract (PT) and explore the side and handedness effects on the microstructure of the PT in healthy subjects by using a probabilistic tractography. The volume and seven DTI parameters (fractional anisotropy (FA), mean, perpendicular and parallel diffusity, geometric diffusion measures) were determined. The statistical analysis revealed substantial PT asymmetries and an average correlation between FA, mean diffusity and the laterality quotient.