Apparent Diffusion Coefficient of Gd-Based Contast Agents Assessed in Vivo in the Rat Brain Using Dynamic T1 Mapping

Benjamin Marty¹, Julien Flament¹, Cline Giraudeau¹, Caroline Robic², Marc Port², Franck Lethimonnier¹, Fawzi Boumezbeur¹, Julien Valette¹, Denis Le Bihan¹, Sbastien Mriaux¹

Gadolinium-based contrast agents (Gd-based CA) have been used for many years for various MRI applications including MR-based molecular imaging with targeted compounds. One of the most important factors to consider for brain applications is the diffusivity of these probes through the cerebral tissue to their target. This study proposes a methodology allowing quantification of Gd-based CA concentration by acquiring dynamic T1 maps. This approach has been applied to estimate in vivo in the rat brain the apparent diffusion coefficient of five compounds with different hydrodynamic diameters opening the way to a better understanding of diffusion mechanisms of supra-molecular imaging probes.