Regional Finite Strains in an Angiotensin-II Induced Mouse Model of Dissecting Abdominal Aortic Aneurysms

Abstract

Abdominal aortic aneurysms are focal dilatations of the aorta; they typically progress to rupture, which is responsible for increasing morbidity and mortality in our aging society. It is well accepted that rupture occurs when wall stress exceeds strength, and there have been many advances over the past two decades in predicting local stresses based on patient-specific computational models. Nevertheless, two of the primary continuing limitations of such models are the assumptions of constant (i.e., non-evolving) and spatially homogeneous material properties. Mouse models of aortic aneurysms provide a means to measure evolving heterogeneous properties, but heretofore such attempts have been limited because of the complex geometries of these lesions. In this paper, we present a technical advance—panoramic digital image correlation—that can aid in the final goal of determining regional mechanical properties in mouse models of aneurysms. We show, as illustrative data, the first detailed quantification of full field surface strains for experimentally distended mouse aneurysms, data which will be fundamental to future inverse determinations of regional material properties.