title: A tract-specific framework for white matter morphometry combining macroscopic and microscopic tract features.
abstract: Diffusion tensor imaging plays a key role in our understanding of white matter (WM) both in normal populations and in populations with brain disorders. Existing techniques focus primarily on using diffusivity-based quantities derived from diffusion tensor as surrogate measures of microstructural tissue properties of WM. In this paper, we describe a novel tract-specific framework that enables the examination of WM morphometry at both the macroscopic and microscopic scales. The framework leverages the skeleton-based modeling of sheet-like WM fasciculi using the continuous medial representation, which gives a natural definition of thickness and supports its comparison across subjects. The thickness measure provides a macroscopic characterization of WM fasciculi that complements existing analysis of microstructural features. The utility of the framework is demonstrated in quantifying WM atrophy in Amyotrophic Lateral Sclerosis, a severe neurodegenerative disease of motor neurons. We show that, compared to using microscopic features alone, combining the macroscopic and microscopic features gives a more holistic characterization of the disease.
authors.affiliation: Penn Image Computing and Science Laboratory, Department of Radiology, University of Pennsylvania, Philadelphia, USA.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.forename: Suyash P
authors.initials: SP
authors.lastname: Awate
authors.forename: Sandhitsu R
authors.initials: SR
authors.lastname: Das
authors.forename: John H
authors.initials: JH
authors.lastname: Woo
authors.forename: Elias R
authors.initials: ER
authors.lastname: Melhem
authors.forename: James C
authors.initials: JC
authors.lastname: Gee
authors.forename: Paul A
authors.initials: PA
authors.lastname: Yushkevich
mesh_terms: D000465:Algorithms; D001921:Brain / Q000166:cytology*; D056324:Diffusion Tensor Imaging / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D009413:Nerve Fibers, Myelinated / Q000648:ultrastructure*; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity