The analysis of kidney diffusion patterns with non-linear least square method in AKI

Motivation: Diffusion components and the initial values must be specified in advance in IVIM, which might not be sensible in tissues with complicated diffusion characteristics. Goal(s): To reveal the changes of diffusion patterns of kidney in acute kidney injury (AKI). Approach: Non-negative least squares (NNLS) method shown to derive the number of compartments from the data, rather than to impose it in the analysis of diffusion signals was employed. Results: The volume fraction of tubular or/and vascular decreased significantly and restricted tissue water diffusion was detected in AKI. Impact: Our results suggest that NNLS model is potentially a valuable tool for accurate description of diffusion in kidney.