Optimal Parameters of Diffusion MRI measuring Corticospinal Tract Integrity in healthy subjects

Diffusion weighted imaging (DWI-MRI) is debatably the method of choice for characterizing brain microstructure non-invasively and in vivo in the chronic phase post-stroke. In fact, the degree of motor impairment after stroke is closely linked to the structural integrity of the corticospinal tract (CST). The aim of our study was to extract tract biophysical characteristics such as fractional anisotropy (FA) and Apparent Diffusion Coefficient (ADC) from the CST and to identify the optimal parameters of measuring CST integrity. We conduct experiments with ten healthy human subjects. For each subject, biophysical values were calculated for two Regions of Interest (the posterior limb of the internal capsule and the anterior pons) at two b-value (b=1000s/mm2 and b=3000 s/mm2). In this work, our results showed that the pons region more accurately predict CST integrity than the posterior limb of internal capsule using a b-value equal to 1000 s/mm2. FA and ADC are a promising metric for clinical applications.