Investigation of the mechanical, collagen microstructural, and morphological properties of human intracranial aneurysms

Abstract

Intracranial aneurysms (ICAs) are focal dilations of cerebral arteries caused by the weakening of the arterial wall. The resulting changed hemodynamics can further lead to stress and growth of the site until it eventually ruptures. The morbidity and mortality of a ruptured aneurysm are high, even after treatment, with many dying within months of the occurrence or suffering from lifelong disability [1]. Previous studies have separately examined the hemodynamics, mechanical properties, or morphology of human aneurysm tissues. The present work provides quantitative data on a resected human cerebral aneurysm's mechanical, collagen fiber microstructural, and morphological characteristics. The mechanical properties of the tissue were characterized using biaxial tension and stress relaxation tests. The tissue's collagen fiber architecture and its load-dependent changes were then examined using a polarized spatial frequency domain imaging system. The microstructural components of the tissue were quantified using histological procedures. This investigation extends on our previously developed characterization framework [2] and provides additional quantitative information on human cerebral artery aneurysms. Such investigations of these properties can provide essential insight into the evolution of aneurysms and their associated rupture risk, which can ultimately improve our fundamental understanding of aneurysm growth critical for the future development of aneurysm therapeutics with improved outcomes.