Trends in Diffusion MRI Tractography

Carl-Fredrik Westin
Harvard Medical School

In this talk I will present an overview of different types of diffusion MRI tractography methods available. Tractography is a promising method for tracing and visualizing bundles of white matter fiber tracts in the brain in-vivo. A simple and effective method for tracing nerve fibers, often called stream-line tractography, uses diffusion measurements from MRI and follows the direction of the maximum diffusion along the path. Although the stream-line method is widely used, it suffers from some major disadvantages. The connectivity is restricted to a one-to-one mapping between points, not allowing the branching that real nerve fibers may undergo. It also gives the impression of being precise, not taking the uncertainty of fiber paths into account in the tracing procedure. Several alternative methods are available and actively researched. For example, stochastic methods have been proposed and have the advantage that they can model uncertainty. Methods based on heat/diffusion simulations have been proposed and have the advantage to be closely related to the data. Geometric geodesic approaches have been proposed and have the advantage to cast the problem into defining distances between locations in the brain, and thus providing a geometrically intuitive meaning of tractography. On overview of the most widely used methods will be given, and their strengths and weaknesses will be discussed.

Audio (MP3 File, Podcast Ready)

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