Acoustic radiation force impulse imaging of the mechanical properties of arteries: in vivo and ex vivo results.

We present results of a pilot study of ex vivo and in vivo acoustic radiation force impulse (ARFI) imaging demonstrating measurements of the mechanical properties of the carotid and popliteal arteries. The results were obtained on a modified commercial scanner, providing coregistered B-mode and color Doppler images. 2D and 1D through time images are formed from the measurements of tissues' response to very brief and localized applications of radiation force. The images show good correlation with B-mode and, in ex vivo studies, pathology-based characterizations of vessel geometry and plaque stiffness. In vivo measurements of arterial response during both systole and diastole are presented. We address implementation issues and discuss potential applications of this new vascular imaging method.