High fidelity fiber orientation density functions from fiber ball imaging. (12th September 2021)

• Record Type: Journal Article
• Authors: Moss, Hunter G.; Jensen, Jens H.
• Is Part Of: NMR in biomedicine. Volume 35:Number 1(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-09-12
• Subjects: angular resolution -- diffusion MRI -- fiber ball imaging -- fiber orientation density function -- high b‐value -- white matter; Nuclear magnetic resonance -- Periodicals; Magnetic Resonance Spectroscopy -- Periodicals; 574
• DOI: 10.1002/nbm.4613
• Languages: English
• ISSNs: 0952-3480

Abstract

Abstract : The fiber orientation density function (fODF) in white matter is a primary physical quantity that can be estimated with diffusion MRI. It has often been employed for fiber tracking and microstructural modeling. Requirements for the construction of high fidelity fODFs, in the sense of having good angular resolution, adequate data to avoid sampling errors, and minimal noise artifacts, are described for fODFs calculated with fiber ball imaging. A criterion is formulated for the number of diffusion encoding directions needed to achieve a given angular resolution. The advantages of using large b ‐values (≥6000 s/mm 2 ) are also discussed. For the direct comparison of different fODFs, a method is developed for defining a local frame of reference tied to each voxel's individual axonal structure. The Matusita anisotropy axonal is proposed as a scalar fODF measure for quantifying angular variability. Experimental results, obtained at 3 T from human volunteers, are used as illustrations. Abstract : Construction of high fidelity fiber orientation functions with fiber ball imaging benefits from a large number of diffusion encoding directions (>80) and a high b ‐value (>6000 s/mm 2 ). For quantitative comparison across brain regions and subjects, the Matusita distance can be used together with a local frame of reference defined in terms of axonal microstructure. Angular resolutions of about 20° are feasible on clinical scanners.