title: Quantitative representation and description of intravoxel fiber complexity in HARDI.
abstract: Diffusion tensor imaging and high angular resolution diffusion imaging are often used to analyze the fiber complexity of tissues. In these imaging techniques, the most commonly calculated metric is anisotropy, such as fractional anisotropy (FA), generalized anisotropy (GA), and generalized fractional anisotropy (GFA). The basic idea underlying these metrics is to compute the deviation from free or spherical diffusion. However, in many cases, the question is not really to know whether it concerns spherical diffusion. Instead, the main concern is to describe and quantify fiber complexity such as fiber crossing in a voxel. In this context, it would be more direct and effective to compute the deviation from a single fiber bundle instead of a sphere. We propose a new metric, called PEAM (PEAnut Metric), which is based on computing the deviation of orientation diffusion functions (ODFs) from a single fiber bundle ODF represented by a peanut. As an example, the proposed PEAM metric is used to classify intravoxel fiber configurations. The results on simulated data, physical phantom data and real brain data consistently showed that the proposed PEAM provides greater accuracy than FA, GA and GFA and enables parallel and complex fibers to be better distinguished.
authors.affiliation: CREATIS, CNRS UMR 5220, Inserm U1044, INSA of Lyon, University of Lyon, Villeurbanne 69100, France. CNRS LIA Metislab, Harbin Institute of Technology, Harbin 150001, People's Republic of China.
authors.forename: Chang-yu
authors.initials: CY
authors.lastname: Sun
authors.forename: Chun-yu
authors.initials: CY
authors.lastname: Chu
authors.forename: Wan-yu
authors.initials: WY
authors.lastname: Liu
authors.forename: Edward W
authors.initials: EW
authors.lastname: Hsu
authors.forename: Julie R
authors.initials: JR
authors.lastname: Korenberg
authors.forename: Yue-min
authors.initials: YM
authors.lastname: Zhu
mesh_terms: D000465:Algorithms; D016880:Anisotropy; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D056324:Diffusion Tensor Imaging / Q000379:methods*