Computational model of the convection-enhanced delivery of large molecules into the striatum of the adult brain

To overcome the blood-brain barrier (BBB) a neurological drug can be delivered directly into the parenchyma via catheter, allowing for specific targeting of the drug to a region of interest. This approach, called convection enhanced delivery (CED), uses the velocity distribution from the catheter tip to spread the drug further than would be realized with simple diffusion. A computational model has been developed to help determine the specific CED distribution of an intraparenchymal delivery of a large molecule to the striatum. Using the MRI images of an adult female, a 3D finite-element model containing the caudate, putamen, internal capsule, ventricles and a spherical infusion point has been constructed. Darcy's law and the convection/diffusion equation were solved for a chronic infusion, taking into account the larger hydraulic permeability in white matter, as well as the interstitial fluid clearance. The results of the model determined the volume of distribution of the drug in the extracellular space.