ISMRM 25th Annual Meeting & Exhibition 22-27 April 2017 Honolulu, HI, USA

Sunrise Educational Session: Local vs. Global Tractography
Sunrise Session

ORGANIZERS: Daniel C. Alexander, Ph.D. & Jennifer A. McNab, Ph.D.

Thursday, 27 April 2017
Room 315  07:00 - 07:50 Moderators: Fulvia Palesi, Jacques-Donald Tournier

Skill Level: Intermediate

Slack Channel: #e_diff_perf_fmri
Session Number: STh03

This course contrasts local and global tractography approaches to highlight the advantages and disadvantages of each. It further explores how they may be integrated to increase the accuracy of future fiber tracking.

Target Audience
Physicists, Scientists, Clinicians interested in diffusion tractography methods.

Educational Objectives
Upon completion of this course, participants should be able to:

-Recognize the difference between local and global tractography approaches;
-Assess the unique benefits and challenges of local and global tractography; and
-Convey how local and global tractography methods may be integrated - semi-local methods.

Local Tractography
Lauren O'Donnell
This educational talk will describe and explain local tractography, a popular class of tractography methods that use diffusion MRI data to reconstruct white matter fiber tracts by making local decisions. These local decisions are choices that are made at each tracking step, such as the choice of the direction in which to take the next step. An overview of local tractography methods will be given, including both deterministic and probabilistic approaches. Benefits and challenges of local tractography methods will be described, along with important clinical and neuroscience research applications of local tractography.

Global Tractography
Marco Reisert, Valerij Kiselev, Dmitry Novikov
There are two overarching challenges of clinical diffusion-weighted magnetic resonance imaging: the estimation of long-range structural connectivity, and second, the quantification of tissue properties at the a cellular scale of micrometers. Here we propose a global optimization framework that tries to resolve both challenges for human white matter fibers, by unifying global fiber tractography and intra-voxel mesoscopic modeling. The algorithm is based on a Simulated Annealing approach which simultaneously optimizes diffusion parameters and fiber locations. Additionally, fibers can carry their individual set of diffusion microparameters which allows to link them by their structural relationships.

Integration of Local & Global Tractography
Robert Smith
A new class of diffusion MRI tractography processing methods is emerging, that involve the integration of ideas from existing "local" and "global" tractography algorithms in order to inherit the benefits of both. In this article, the basic premise behind these methods is explained, the history and details of these methods are provided, and the consequences and importance of these developments is contextualised.

Panel Discussion

The International Society for Magnetic Resonance in Medicine is accredited by the Accreditation Council for
Continuing Medical Education to provide continuing medical education for physicians.