title: ATLAS-BASED FIBER CLUSTERING FOR MULTI-SUBJECT ANALYSIS OF HIGH ANGULAR RESOLUTION DIFFUSION IMAGING TRACTOGRAPHY.
abstract: High angular resolution diffusion imaging (HARDI) allowsin vivoanalysis of the white matter structure and connectivity. Based on orientation distribution functions (ODFs) that represent the directionality of water diffusion at each point in the brain, tractography methods can recover major axonal pathways. This enables tract-based analysis of fiber integrity and connectivity. For multi-subject comparisons, fibers may be clustered into bundles that are consistently found across subjects. To do this, we scanned 20 young adults with HARDI at 4 T. From the reconstructed ODFs, we performed whole-brain tractography with a novel Hough transform method. We then used measures of agreement between the extracted 3D curves and a co-registered probabilistic DTI atlas to select key pathways. Using median filtering and a shortest path graph search, we derived the maximum density path to compactly represent each tract in the population. With this tract-based method, we performed tract-based analysis of fractional anisotropy, and assessed how the chosen tractography algorithm influenced the results. The resulting method may expedite population-based statistical analysis of HARDI and DTI.
authors.affiliation: Laboratory of Neuro Imaging, Department of Neurology, UCLA School of Medicine, Los Angeles, CA, USA.
authors.forename: Gautam
authors.initials: G
authors.lastname: Prasad
authors.affiliation: Laboratory of Neuro Imaging, Department of Neurology, UCLA School of Medicine, Los Angeles, CA, USA.
authors.forename: Neda
authors.initials: N
authors.lastname: Jahanshad
authors.affiliation: Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Iman
authors.initials: I
authors.lastname: Aganj
authors.affiliation: Department of Radiology - CMRR, University of Minnesota Medical School, Minneapolis, MN, USA.
authors.forename: Christophe
authors.initials: C
authors.lastname: Lenglet
authors.affiliation: Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Sapiro
authors.affiliation: Laboratory of Neuro Imaging, Department of Neurology, UCLA School of Medicine, Los Angeles, CA, USA.
authors.forename: Arthur W
authors.initials: AW
authors.lastname: Toga
authors.affiliation: Laboratory of Neuro Imaging, Department of Neurology, UCLA School of Medicine, Los Angeles, CA, USA.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Thompson
keywords: Dijkstra’s shortest path; clustering; fiber bundles; multi-subject analysis; tractography