Quantitative assessment of diffusional kurtosis anisotropy. (26th February 2015)

• Record Type: Journal Article
• Authors: Glenn, G. Russell; Helpern, Joseph A.; Tabesh, Ali; Jensen, Jens H.
• Is Part Of: NMR in biomedicine. Volume 28:Number 4(2015:Apr.)
• Page Start: 448
• Page End: 459
• Publication Date: 2015-02-26
• Subjects: DKI -- kurtosis -- anisotropy -- FA -- KFA -- GFA -- diffusion -- non‐Gaussian; Nuclear magnetic resonance -- Periodicals; Magnetic Resonance Spectroscopy -- Periodicals; 574
• DOI: 10.1002/nbm.3271
• Languages: English
• ISSNs: 0952-3480

Abstract

Abstract : Diffusional kurtosis imaging (DKI) measures the diffusion and kurtosis tensors to quantify restricted, non‐Gaussian diffusion that occurs in biological tissue. By estimating the kurtosis tensor, DKI accounts for higher order diffusion dynamics, when compared with diffusion tensor imaging (DTI), and consequently can describe more complex diffusion profiles. Here, we compare several measures of diffusional anisotropy which incorporate information from the kurtosis tensor, including kurtosis fractional anisotropy (KFA) and generalized fractional anisotropy (GFA), with the diffusion tensor‐derived fractional anisotropy (FA). KFA and GFA demonstrate a net enhancement relative to FA when multiple white matter fiber bundle orientations are present in both simulated and human data. In addition, KFA shows net enhancement in deep brain structures, such as the thalamus and the lenticular nucleus, where FA indicates low anisotropy. Thus, KFA and GFA provide additional information relative to FA with regard to diffusional anisotropy, and may be particularly advantageous for the assessment of diffusion in complex tissue environments. Copyright © 2015 John Wiley & Sons, Ltd. Abstract : Quantitative measures of diffusion anisotropy are important for the assessment of features of tissue microstructure from diffusion MRI data. We define and motivate a novel measure of anisotropy in the fourth‐order kurtosis tensor, termed 'fractional kurtosis anisotropy (KFA)', which is mathematically analogous to fractional anisotropy (FA), a popular measure from the diffusion tensor. KFA provides distinct and complementary information about diffusion anisotropy and demonstrates a net enhancement relative to FA when complex diffusion profiles are present in both simulated and human experiments.