Theoretical Modeling of Enlarging Intracranial Aneurysms

Abstract

Rupture of intracranial aneurysms is the leading cause of spontaneous subarachnoid hemorrhage, which results in significant morbidity and mortality. The mechanisms by which intracranial aneurysms develop, enlarge, and rupture are unknown, and it remains difficult to collect the longitudinal patient-based information needed to improve our understanding. We suggest, therefore, that mathematical models hold considerable promise by allowing us to propose and test competing hypotheses on potential mechanisms of aneurysmal enlargement and to compare predicted outcomes with limited clinical information; in this way, we may begin to narrow the possible mechanisms and thereby focus experimental studies. Toward this end, we develop a constrained mixture model for evolving thin-walled, saccular, and fusiform aneurysms and illustrate its efficacy via computer simulations of lesions having idealized geometries. We also present a method to estimate linearized material properties over the cardiac cycle, which can be exploited when solving coupled fluid-solid interactions in a lesion