Anna Caroli1, Luca Antiga1, Giuseppe Petralia2, Massimo Bellomi2, Andrea Remuzzi1,3, Paul Summers2
1Bioengineering Department, Mario Negri Institute for Pharmacological Research, Bergamo, Italy; 2Division of Radiology, European Institute of Oncology, Milan, Italy; 3University of Bergamo, Bergamo, Italy
Mono-exponential models do not accurately predict diffusion-weighted signal decay in the kidney, while bi-exponential models are unable to differentiate contributions. We propose a piece-wise exponential model, separately fitting low and high b-values with two exponentials, expressive of fast and slow transport components. Ten healthy volunteers underwent DWI both pre- and post-lunch, and acquisitions were repeated within one of the two sessions. The model was stable, and accurately fit signal attenuation. Diffusion parameters showed high repeatability, but significant differences between pre- and post-meal acquisitions. These results point out the need for more complete interpretations of DWI signal in describing the complex transport in the kidney.