The advent of ultrafast ultrasound in vascular imaging: a review

Abstract: In the last 10 years the advent of computational power and the availability of fully programmable research ultrasound imaging systems have allowed the emergence of ultrafast ultrasound imaging (<1000 frames per second), which has become a central research topic in the ultrasound community. Ultrafast ultrasound imaging relies deeply on the capability of massive parallel beamforming/processing of a single transmit ultrasound event insonifying a large field of view. This ultrafast acquisition capability opens up new tradeoffs in terms of processing and observations of transient rapid phenomena. Firstly, it can be used to improve conventional imaging modes such as B-mode, Doppler modes, Contrast Enhanced Ultrasound in terms of sensitivity, contrast, spatial, and/or temporal resolutions. It can also enrich conventional color flow imaging modes by providing quantitative and synchronous spectral information on the whole image. Secondly it can be used to capture transient phenomena that where unseen with conventional frame rates (<50 Hz) enabling completely novel imaging modes such as real time shear wave elastography (SWE), a technique for mapping quantitatively soft tissue elasticities, or ultrafast PWV, a technique for measuring locally the pulse wave velocity (PWV). In this review, we first introduce the theoretical basis of ultrafast imaging. We then present a state of the art of ultrafast ultrasound imaging in the specific field of arterial wall mechanical properties characterization. Keywords: ultrafast imaging, SWE, PWV, arterial stiffness, ultrasound