Diffusion Kurtosis Imaging (DKI) is a method for quantifying the degree to which water diffusion in biological tissues is non Gaussian. Since tissue structure is responsible for the deviation of water diffusion from the Gaussian behavior typically observed in homogeneous solutions, this method provides a specific measure of tissue structure, such as cellular compartments and membranes. We can distinguish the anisotropic Gaussian distribution with an extend form of DTI. DKI protocols differ from DTI protocols in requiring at least 3 b-values (as compared to 2 b-values for DTI) and at least 15 independent diffusion gradient directions (as compared to 6 for DTI). Typical protocols for brain have b-values of 0, 1000, 2000 s/mm2 (the higher b value the better as long as you have adequate SNR) with 30 diffusion directions. Image post-processing requires the use of specialized algorithms which can generate a set of kurtosis (mean, axial, radial) parametric maps.
