Quantitative assessment of diffusional kurtosis anisotropy

NMR Biomed. 2015 Apr;28(4):448-59. doi: 10.1002/nbm.3271. Epub 2015 Feb 26.


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.

Keywords: DKI; FA; GFA; KFA; anisotropy; diffusion; kurtosis; non-Gaussian.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Algorithms
  • Anisotropy
  • Datasets as Topic
  • Diffusion Magnetic Resonance Imaging / methods
  • Diffusion Magnetic Resonance Imaging / statistics & numerical data*
  • Diffusion Tensor Imaging / methods
  • Diffusion Tensor Imaging / statistics & numerical data*
  • Female
  • Humans
  • Image Processing, Computer-Assisted
  • Male
  • Middle Aged
  • Normal Distribution
  • White Matter / anatomy & histology*