Non-invasive vascular elastography: a prospective study

Changes in vessel wall elasticity may be indicative of vessel pathologies. Recently, endovascular elastography has been proposed as a tool to complement IVUS echograms in pre-operative lesion assessments and to plan endovascular therapy. In this paper, this technology is introduced as an approach to non-invasively characterize superficial arteries. In such a case, a linear array ultrasound transducer is applied on the skin over the region of interest, and the arterial tissue is dilated by the normal cardiac pulsation. Because tissue motion occurs radially within the vessel wall while the ultrasound beam propagates axially, motion parameters might be difficult to interpret. In this paper, the Von Mises coefficient is proposed as a new parameter to characterize the vessel wall. The Lagrangian estimator was used because it computes the full 2D-strain tensor that is required to provide the Von Mises coefficient. The theoretical model was validated with biomechanical simulations of the vascular wall properties. The results allow believing in the potential of the method to differentiate hard plaques and lipid pools from normal vascular tissue.