APA Dictionary of Psychology

a noninvasive test that allows doctors to estimate the direction, speed, and turbulence of blood flow through a patient’s veins. High-frequency sound waves are bounced off of the blood cells moving through the patient’s blood vessels, and the resulting images are projected onto a monitor. This test is used to look for blood clots, valve problems, aneurysms, and narrowed or blocked arteries, among other circulation problems. See also transcranial Doppler ultrasonography.