A pulsatile flow phantom for image-guided high-intensity focused ultrasound studies on blood vessels

Abstract

A pulsatile flow phantom has been developed for controlled studies of acoustic hemostasis and high intensity focused ultrasound (HIFU) effects on blood vessels. The flow phantom consists of an excised carotid artery attached to a pulsatile pump and embedded in an optically and acoustically transparent gel to create an ex vivo model of a human artery. The artery was punctured with a needle to simulate percutaneous vascular injury. A HIFU transducer with a focal distance of 6 cm and a frequency of 3.33 MHz was used to treat the puncture. B-mode and power-Doppler ultrasound were used to locate the site of the puncture, target the HIFU focus, and monitor treatment. Also, the effects of vascular flow on HIFU lesions were studied by treating vessels in the phantom for different times at a variety of flows. In both studies, histology was done on the artery. In nine trials, HIFU was able to provide complete hemostasis in 55 ± 31 s. It is feasible to use the flow phantom to study acoustic hemostasis of blood vessels. Histology shows that the flow in the phantom appears to diminish the vascular damage from HIFU.