Vascular imaging, also known as vascular ultrasound, uses high-frequency sound waves to study the flow of blood in the arteries and veins of the body. This technique provides vital information regarding blood flow to the arms, legs, kidneys and brain, among other areas. Blockages such as plaque or blood clots can be located with this testing. For a vascular imaging test, you will lie down on a bed or examination table. A jelly-like substance is applied to the skin to improve the transmission of the signal.