Empirical and Theoretical Characterization of the Diffusion Process of Different Gadolinium-Based Nanoparticles within the Brain Tissue after Ultrasound-Induced Permeabilization of the Blood-Brain Barrier.
Allegra ContiRémi MagninMatthieu GerstenmayerNicolas TsapisErik DumontOlivier TillementFrançois LuxDenis Le BihanSébastien MériauxStefania Della PennaBenoit LarratPublished in: Contrast media & molecular imaging (2019)
Low-intensity focused ultrasound (FUS), combined with microbubbles, is able to locally, and noninvasively, open the blood-brain barrier (BBB), allowing nanoparticles to enter the brain. We present here a study on the diffusion process of gadolinium-based MRI contrast agents within the brain extracellular space after ultrasound-induced BBB permeabilization. Three compounds were tested (MultiHance, Gadovist, and Dotarem). We characterized their diffusion through in vivo experimental tests supported by theoretical models. Specifically, by estimation of the free diffusion coefficients from in vitro studies and of apparent diffusion coefficients from in vivo experiments, we have assessed tortuosity in the right striatum of 9 Sprague Dawley rats through a model correctly describing both vascular permeability as a function of time and diffusion processes occurring in the brain tissue. This model takes into account acoustic pressure, particle size, blood pharmacokinetics, and diffusion rates. Our model is able to fully predict the result of a FUS-induced BBB opening experiment at long space and time scales. Recovered values of tortuosity are in agreement with the literature and demonstrate that our improved model allows us to assess that the chosen permeabilization protocol preserves the integrity of the brain tissue.
Keyphrases
- resting state
- white matter
- high glucose
- magnetic resonance imaging
- functional connectivity
- blood brain barrier
- contrast enhanced
- diabetic rats
- randomized controlled trial
- systematic review
- endothelial cells
- magnetic resonance
- computed tomography
- multiple sclerosis
- diffusion weighted imaging
- minimally invasive
- monte carlo