Pulse Wave Imaging for Noninvasive and Quantitative Measurement of Arterial Stiffness In Vivo

BACKGROUND Arterial stiffening is recognized to be associated with increased cardiovascular mortality and to be a major cause of several cardiovascular complications. Pulse wave velocity (PWV) has been widely accepted to be a reliable and robust measure of arterial stiffness. In this article, the novel ultrasound-based pulse wave imaging (PWI) method is hereby proposed for visualization of the pulse wave during its propagation and for calculation of the PWV. METHODS The PWV is estimated by measuring the spatiotemporal variation of the pulse wave-induced displacement of the arterial wall within the imaged segment. The method is compared to mechanical testing on aortic phantoms in order to evaluate its reliability and accuracy, and in vivo results are presented on normal abdominal aortas (N = 11). RESULTS Good agreement was found with mechanical testing on phantoms (r(2) = 0.92), showing the reliability of the method. In vivo average PWV and Young's modulus were found to be equal to 4.4 +/- 0.6 m/s and 108 +/- 27 kPa, respectively. CONCLUSIONS Reliability and in vivo feasibility of the proposed PWI method were demonstrated in this study. Its simplicity of use and its capability of providing regional PWV render PWI a valuable tool for quantitative assessment of arterial stiffness. The utility of the method in a clinical setting has yet to be established and is part of an ongoing clinical study.