A new surgical tool that uses low-frequency ultrasound to break down blood clots deep within the veins of the legs, without damaging the surrounding blood vessels, has been developed by US researchers.

The tool is the first ultrasound "drill" that can be aimed straight ahead, allowing doctors to better target clots and holds promise for significantly reducing treatment time, researchers said."Our new ultrasound tool is forward-facing, like a drill, but still breaks down clots into very fine particles," said Xiaoning Jiang, Professor at the North Carolina State University. Existing intravascular ultrasound tools for clearing clots emit ultrasound waves laterally, making it harder to target clots exclusively, meaning that the ultrasound can also damage surrounding blood vessels. 

The tool also incorporates an injection tube that allows users to inject microbubbles at the site of the clot, making the ultrasound waves more effective at breaking down the clot."Our approach improves accuracy without relying on high doses of blood thinners, which we hope will reduce risks across the board," Jiang added, in the paper detailed in the journal Scientific Reports.The researchers tested a prototype of the device in a synthetic blood vessel using cow's blood."We found that we could dissolve 90 per cent of a clot in 3.5 to 4 hours without using any blood thinners at all. That's compared to 10 hours for the combination of conventional ultrasound tools and blood thinners," Jinwook Kim, doctoral student at the North Carolina State University.