Flow velocity mapping using high frame-rate plane wave ultrasound and microbubble contrast agents – methods and initial in vitro and in vivo evaluation

摘要

Ultrasound imaging is the most widely used method for visualising and quantifying blood flow in medical practice but existing techniques have various limitations in terms of imaging sensitivity, field of view, flow angle dependence and imaging depth. In this study, we developed an ultrasound imaging velocimetry approach capable of visualising and quantifying dynamic flow, by combining high frame-rate plane wave ultrasound imaging, microbubble contrast agents, pulse inversion contrast imaging and speckle tracking algorithms. The system has been initially evaluated in vitro on both straight and carotidmimicking vessels with steady and pulsatile flows, and in vivo in the rabbit aorta. Colour and spectral Doppler measurements were also made. Initial flow mapping results were compared with theoretical prediction and reference Doppler measurements and demonstrate the potential of the new system as a highly sensitive, accurate, angle-independent and full fieldof-view velocity mapping tool capable of tracking and quantifying fast and dynamic flows.