Model-based neuroanatomy: Tractography validation, white-matter connections and geometrical organization

Abstract

Diffusion-weighted MRI (DWI) coupled with fiber tractography allows for non-invasive measurement of the organization of white-matter fascicles in the living human brain. Investigators can choose between many possible DWI measurements and tractography algorithms to estimate a full set of white-matter fascicles; the connectome. Each algorithm, creates connectomes based on different principles, such differences make connectome measurements dependent not only on the brain biology but also on tractography (e.g., Fig 1A; Fascicles identified with two different tractography algorithms). Hereafter, we propose a method for validating connectomes based on both their geometric consistency and their quality in predicting the diffusion signal. We apply this method to study the geometric structure of white-matter fibers.