Diffusion-compensated tofts model suggests contrast leakage through aneurysm wall

Purpose: The purpose of this study was to investigate the diffusional transport of contrast agent and its effects on kinetic modeling of dynamic contrast enhanced (DCE) images. Methods: We performed simulations of our diffusion-compensated model and compared these results to human intracranial aneurysms (IAs). We derive an easy-to-use parameterization of diffusional effects that can provide an accurate estimate of diffusion corrected contrast agent leakage rates (k^trans). Finally, we performed re-ansalysis of an existing data set to determine whether diffusion-corrected kinetic parameters improve the identification of high-risk IAs, thereby providing a new MRI-based imaging metric of IA stability based on wall integrity. Results: Probability distributions of simulated versus measured data show contrast leakage away from the aneurysm wall. Parameterization of diffusional effects on k^trans showed high correlation with long-chain methods in both surrounding tissue and near the aneurysm wall (r² = 0.91 and r² = 0.90, respectively). Finally, size, k^trans, and (k^trans-k^trans _DC) showed significant univariate relationships with rupture risk (P < 0.05). Conclusions: We report the first evidence of diffusion-compensated permeability modeling in intracranial aneurysms and propose a parameterization of diffusional effects on k^trans. Furthermore, a comparison of measured versus simulated data suggests that contrast leakage occurs across the aneurysm wall. Magn Reson Med 78:2388–2398, 2017.