Thalamic Involvement Following Mild Brain Injury: In Vivo Occult Pathology Demonstrated by Diffusion Kurtosis Imaging

DKI) maps in a patient (bottom row) and an age-matched normal control (top row). Note that there is obvious decreased MK level on the parametric maps (thalamic MK) in patient compared to normal control. Such differences were not found on FA and MD maps. The contrast of gray matter and white matter on the MK map is better than on the MD map. For isotropic structures, such as gray matter, MK is superior to FA. This is because on FA maps, the values of gray matter are very low due to its isotropic nature, which makes FA not a sensitive measure for gray matter. FA map also suffers the inhomogeneous pattern of white matter, possibly due to the fiber crossing.