Choosing Tractography Parameters to Improve Connectivity Mapping

International audienceDiffusion-weighted imaging (DWI) is often used as a starting point for in vivo white matter (WM) connectivity to reconstruct potential WM pathways between brain areas. Tractography algorithms have many parameters which can influence reconstruction and connectivity. Various choices of parameters have been proposed. But how does one choose the best set of parameters? In this study, we varied three critical parameters while monitoring connectivity score using the Tractometer evaluation system on the International Symposium on Biomedical Imaging (ISBI) Challenge synthetic dataset. The three parameters were: * θ: The maximum deviation angle between two consecutive tractography steps. This addresses the hypothesis of smoothness of the WM pathways. * τ: The spherical function (SF) threshold. This aims at removing noisy propagation directions during the tractography process. * τ init : The initial SF threshold. This aims at removing initial noise at the seeds and to start tractography in a good tangent direction to the WM bundle