Researchers at Washington University in St. Louis have found a method to test blood circulation in the small, slow-moving vessels that can’t be detected by standard ultrasound methods. The method uses sonic blasts to boil a miniscule portion of your blood. While this may sound painful, the researchers claim that you’d only feel a slight warming sensation.

Currently, doctors use ultrasound to measure blood flow in the body. Doppler effect, just like bats! But it can’t detect flow in the small, slow-moving vessels where diseases often start. The solution? Sonic blasts that heat up a tiny drop of blood, then watch where it goes. Science!