Review on the formation and growth of cerebral aneurysms

Abstract

A cerebral aneurysm is a vascular condition characterized by local ballooning of an artery in the brain. Although aneurysm formation and growth are thought to be the result of destruction of the blood vessel wall, the details of the etiology are unclear. We review the formation and growth of cerebral aneurysms as follows. In the first part, we summarize the history of theories on the pathogenesis of cerebral aneurysm in chronological order from epidemiological and pathological viewpoints and based on data obtained from animal models of experimentally induced cerebral aneurysms, with a focus on the involvement of hemodynamic stress on the arterial wall. In the second part, we review computational fluid dynamics (CFD) studies on the initiation of cerebral aneurysms with a brief overview of the history of CFD in hemodynamics analysis. Of the hypotheses presented, strong emphasis is placed on that of high wall shear stress and a high wall shear stress gradient. Other leading hypotheses involving hemodynamics-related parameters are also reviewed. In the third part, we review CFD studies on the growth of cerebral aneurysms, in which hemodynamic parameters were compared between growing and stable aneurysms, to highlight the hemodynamic characteristics associated with their growth.