Scientific computing challenges for macroscopic and microscopic hemodynamics

Abstract

Recent advances in scientific computing have enabled the study of realistic 3D problems in a timely manner. At the macroscopic level, the acquisition of high resolution medical images has made possible the reconstruction of patient-specific models of cerebral aneurysms, human brain vascular structures, lungs, kidneys, etc. These models provide detailed information about patient-specific hemodynamic variables thatwould not be available otherwise. At the microscopic level, advances in the simulation of biophysical processes have enabled the quantification of shape transitions of human red blood cells and the optimization of drug encapsulation/delivery structures. This project adresses three complementary problems in order to push the state of the art of medicine assistedby scientific computing. First we propose to study appropriate boundary conditions on patient-specific models of human brain arterial networks. Realistic simulations of these arterial networks are important to characterize thehemodynamics in the brain and thus study the mechanisms of vascular diseases like aneurysms or stenoses. Current approaches are based on general rules that yield blood flows outside physiological ranges. Second, we propose to study the intra-aneurysmal hemodynamic conditions that are associated with fast aneurysm occlusion after treatment with flow diverting devices. Currently, objective prognostication of the long term outcome of flow diversion treatment is not possible because it is not known exactly whathemodynamic conditions induce fast, organized, stable and complete aneurysm occlusion. Third, we will work in extending the capabilities of an already developed finite element viscous membrane solver for modeling lipidic bilayers in order to be able to perform very large deformations.Lipidic bilayers are the basic constituent of the living cell membranes like those found in red blood cells. Possible applications of this type ofsimulations are numerous, including shape transformations and tethering phenomena.