Tri- and bi-exponential diffusion analyses of the kidney: effect of respiratory-controlled acquisition on diffusion parameters

This study examined whether respiratory-controlled acquisition influences diffusion parameters obtained with intravoxel incoherent motion (IVIM) analysis using tri-exponential and bi-exponential models. Ten healthy volunteers were examined on a 3.0  T MRI system to obtain coronal diffusion-weighted images of both kidneys. The participants were scanned twice using respiratory-triggering (RT) and free-breathing (FB) acquisition to assess the repeatability of the measurements. We determined mean signal intensities in the renal cortex at eachbvalue. Then, perfusion-related diffusion coefficient (Dp), fast-free diffusion coefficient (Df), slow-restricted diffusion coefficient (Ds), and their corresponding fractions (Fp,Ff, andFs, respectively) were calculated using tri-exponential function. Moreover, perfusion-related diffusion coefficient (D*), the fraction (F), and perfusion-independent diffusion coefficient (D) were calculated using bi-exponential function. Normalized root-mean-square errors for the tri- and bi-exponential analyses (nRMSEtri and nRMSEbi, respectively) were determined to assess the deviation of the fitted to measured data, i.e., the fitting accuracy. Additionally, repeatability coefficients (RCs) were calculated from Bland –Altman plots to evaluate the repeatability of each diffusion parameter. These values were compared between the RT and FB groups.Dp andD* in the RT group were significantly lower than those in the FB group (P <  0.05). In addition, t...

Source: Radiological Physics and Technology - July 31, 2023 Category: Physics Source Type: research