Vascular studies are a noninvasive procedure used to assess the blood flow in arteries and veins. A transducer is placed on the skin at certain locations and angles and sends out ultrasonic sound waves through the skin and other body tissues to the blood vessels, where the waves echo off of the blood cells. The transducer picks up the reflected waves and sends them to an amplifier, which makes the ultrasonic sound waves audible.
Vascular studies can utilize one of these special types of ultrasound technology:
Doppler Ultrasound. This technique is used to measure and assess the flow of blood through the blood vessels. The amount of blood pumped with each beat is an indication of the size of a vessel’s opening. Doppler can detect abnormal blood flow within a vessel, which can indicate a blockage caused by a blood clot, a plaque, or inflammation.
Color Doppler. This is an enhanced form of doppler ultrasound technology. With color doppler, different colors are used to designate the direction of blood flow. This simplifies the interpretation of the doppler technique.
To assess blood flow in the limbs, pulse volume recordings (PVRs) may be performed. Blood pressure cuffs are inflated on the limb and blood pressure in the limb is measured using the doppler transducer.
To assess the carotid arteries in the neck, a carotid duplex scan may be performed. This type of doppler examination provides a 2-dimensional (2D) image of the arteries so that the structure of the arteries and location of an occlusion (blockage) or stenosis (narrowing) can be determined, as well as the degree of blood flow.