Comparison of cumulant expansion and q-space imaging estimates for diffusional kurtosis in brain.

摘要: Abstract Purpose To compare estimates for the diffusional kurtosis in brain as obtained from a cumulant expansion (CE) of diffusion MRI (dMRI) signal and q-space (QS) imaging. Theory methods For CE kurtosis, was truncated to quadratic order b-value fit dMRI b-values 0 up 2000 s/mm2. QS estimates, ranging 10,000 s/mm2 were used determine displacement probability density function (dPDF) via Stejskal's formula. The then calculated directly second fourth moments dPDF. These two approximations studied vivo human data on 3 T scanner using three orthogonal encoding directions. Results whole mean values differed by 16% or less each considered directions, Pearson correlation coefficients all exceeded 0.85. Nonetheless, there large discrepancies many voxels, particularly those with either very high low kurtoses relative values. Conclusion Estimates are strongly correlated, suggesting that they encode similar information. However, choice employed here, may be substantial differences, depending properties microenvironment voxel.