title: Automatic clustering of white matter fibers in brain diffusion MRI with an application to genetics.
abstract: To understand factors that affect brain connectivity and integrity, it is beneficial to automatically cluster white matter (WM) fibers into anatomically recognizable tracts. Whole brain tractography, based on diffusion-weighted MRI, generates vast sets of fibers throughout the brain; clustering them into consistent and recognizable bundles can be difficult as there are wide individual variations in the trajectory and shape of WM pathways. Here we introduce a novel automated tract clustering algorithm based on label fusion--a concept from traditional intensity-based segmentation. Streamline tractography generates many incorrect fibers, so our top-down approach extracts tracts consistent with known anatomy, by mapping multiple hand-labeled atlases into a new dataset. We fuse clustering results from different atlases, using a mean distance fusion scheme. We reliably extracted the major tracts from 105-gradient high angular resolution diffusion images (HARDI) of 198 young normal twins. To compute population statistics, we use a pointwise correspondence method to match, compare, and average WM tracts across subjects. We illustrate our method in a genetic study of white matter tract heritability in twins.
authors.affiliation: Imaging Genetics Center, University of Southern California, Los Angeles, CA 90089, USA; Institute for Neuroimaging & Informatics, Departments of Neurology, University of Southern California, Los Angeles, CA 90089, USA. Electronic address: yjinz@ucla.edu.
authors.forename: Yan
authors.initials: Y
authors.lastname: Jin
authors.affiliation: Institute for Neuroimaging & Informatics, Departments of Neurology, University of Southern California, Los Angeles, CA 90089, USA. Electronic address: yonggans@usc.edu.
authors.forename: Yonggang
authors.initials: Y
authors.lastname: Shi
authors.affiliation: Imaging Genetics Center, University of Southern California, Los Angeles, CA 90089, USA; Institute for Neuroimaging & Informatics, Departments of Neurology, University of Southern California, Los Angeles, CA 90089, USA. Electronic address: zhan.liang@gmail.com.
authors.forename: Liang
authors.initials: L
authors.lastname: Zhan
authors.affiliation: Imaging Genetics Center, University of Southern California, Los Angeles, CA 90089, USA; Institute for Neuroimaging & Informatics, Departments of Neurology, University of Southern California, Los Angeles, CA 90089, USA. Electronic address: bgutman@gmail.com.
authors.forename: Boris A
authors.initials: BA
authors.lastname: Gutman
authors.affiliation: School of Psychology, University of Queensland, St. Lucia, QLD 4072, Australia. Electronic address: greig.dezubicaray@uq.edu.au.
authors.forename: Greig I
authors.initials: GI
authors.lastname: de Zubicaray
authors.affiliation: Centre for Advanced Imaging, University of Queensland, St. Lucia, QLD 4072, Australia. Electronic address: katie.mcmahon@cai.uq.edu.au.
authors.forename: Katie L
authors.initials: KL
authors.lastname: McMahon
authors.affiliation: QIMR Berghofer Institute of Medical Research, Herston, QLD 4029, Australia. Electronic address: margie.wright@qimr.edu.au.
authors.forename: Margaret J
authors.initials: MJ
authors.lastname: Wright
authors.affiliation: Institute for Neuroimaging & Informatics, Departments of Neurology, University of Southern California, Los Angeles, CA 90089, USA. Electronic address: toga@usc.edu.
authors.forename: Arthur W
authors.initials: AW
authors.lastname: Toga
authors.affiliation: Imaging Genetics Center, University of Southern California, Los Angeles, CA 90089, USA; Institute for Neuroimaging & Informatics, Departments of Neurology, University of Southern California, Los Angeles, CA 90089, USA; Department of Psychiatry, Pediatrics, Engineering, Radiology, and Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA. Electronic address: pthomp@usc.edu.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Thompson
mesh_terms: D000328:Adult; D000465:Algorithms; D001271:Atlases as Topic; D001931:Brain Mapping / Q000379:methods*; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D009413:Nerve Fibers, Myelinated; D066127:White Matter / Q000033:anatomy & histology*; D055815:Young Adult
keywords: Fiber clustering; Genetic heritability; HARDI; Label fusion; Tractography