Acoustic radiation force impulse imaging on ex vivo abdominal aortic aneurysm model

A method for reliable, noninvasive estimation of abdominal aortic aneurysms (AAA) wall mechanics may be a useful clinical tool for rupture prediction. An in vitro AAA model was developed from an excised porcine aorta with elastase treatment. The AAA model behaviour was analysed using acoustic radiation force impulse (ARFI) imaging techniques to generate and measure wave propagation in both aneurysmal and normal aortic tissue. Opening angle measurement showed a fourfold decrease from healthy aorta to AAA model and pathologic analysis verified this elastin degradation. Maximum wave velocity at 180 mm Hg was 7 mm/ms for healthy tissue and 8.26 mm/ms for the aneurysmal tissue. The mechanical changes produced in the artificially induced aneurysm were found to be detectable using ARFI imaging.