Diffusion-Weighted Imaging of the Kidney: Beyond Mono- And Bi-Exponential Models

Anna Caroli¹, Luca Antiga¹, Giuseppe Petralia², Massimo Bellomi², Andrea Remuzzi^1,3, Paul Summers²

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.