Strain imaging in abdominal aortic aneurysms using bistatic dual-aperture ultrasound.

Abstract

Knowledge of the full geometry of abdominal aortic aneurysms (AAA) and local, mechanical wall parameters using ultrasound (US) can contribute to a better assessment of the AAA's mechanical state, prediction of growth and possible risk of rupture. Such an assessment is currently limited by the anisotropic lumen-wall contrast and the resolution of conventional US. The recent introduction of ultrafast dual-aperture imaging enhances image quality, using two transducers that alternately transmit and receive simultaneously ("bistatic" US). In this study, dual-aperture, bistatic US imaging is assessed in 43 AAA patients. Results were compared to single-aperture ultrafast imaging. Bistatic imaging was demonstrated successfully in 40 patients. Compared to single-aperture imaging, the median wall-lumen generalized contrast-to-noise ratio (gCNR) was significantly increased by 0.13 (+27%). By compounding axial displacements from multiple directions, we show the feasibility of local strain quantification: not only in the vessel wall but also in low contrast regions, such as the intraluminal thrombus (ILT). Multi-aperture ultrasound imaging can provide the clinician with high quality imaging, which contributes towards a better understanding of AAA development and patient-specific rupture risk analysis, by allowing the accurate assessment of tissue properties and function.