(Carotid, Arm, and Leg Arterial and Venous Studies, Carotid Ultrasound, Venous Doppler Studies, Arterial Doppler Studies, Pulse Volume Recordings, PVRS)
What are vascular studies?
Vascular studies are a noninvasive (the skin is not pierced) procedure used to assess the blood flow in arteries and veins. A transducer (like a microphone) sends out ultrasonic sound waves at a frequency too high to be heard. When the transducer is placed on the skin at certain locations and angles, the ultrasonic sound waves move 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, as listed below:
This Doppler 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. Also, 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 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 can be determined, as well as the degree of blood flow.
A carotid artery duplex scan is a type of vascular ultrasound study done to assess occlusion (blockage) or stenosis (narrowing) of the carotid arteries of the neck and/or the branches of the carotid artery. Plaque (a build up of fatty materials), a thrombus (blood clot), and other substances in the blood stream may cause a disturbance in the blood flow through the carotid arteries.
Other related procedures that may be used to assess the heart and circulatory system include resting and exercise electrocardiogram (ECG or EKG), Holter monitor, signal-averaged ECG, cardiac catheterization, chest x-ray, computed tomography (CT scan) of the chest, electrophysiological studies, magnetic resonance imaging (MRI) of the heart, myocardial perfusion scans, radionuclide angiography, and ultrafast CT scan. Please see these procedures for additional information.
The arteries bring oxygen and other nutrients to the cells of the body. The veins take away the blood after the cells have taken in the oxygen and nutrients and given up their waste products, such as carbon dioxide. If blood flow is decreased to any part of the body, that area does not get enough oxygen and nutrients and is unable to get rid of its waste products adequately.
Decreased blood flow can occur in the arteries and veins anywhere in the body, such as the neck and brain. When the neck arteries (carotid arteries) become occluded, symptoms such as dizziness, confusion, drowsiness, headache, and/or a brief loss of ability to speak or move, may be the early warning signs of a possible stroke (brain attack). More severe symptoms, such as sudden sharp headache, loss of vision in one eye, sudden loss of ability to move arms, legs, or one side of the body, sudden forceful vomiting, or sudden decreased level of consciousness may mean that a stroke is imminent.
Some conditions which may affect blood flow include, but are not limited to, the following:
atherosclerosis - a gradual clogging of the arteries over many years by fatty materials and other substances in the blood stream
aneurysm - a dilation of a part of the heart muscle or the aorta (the large artery that carries oxygenated blood out of the heart to the rest of the body), which may cause weakness of the tissue at the site of the aneurysm
embolus or thrombus - clots in blood vessels may be either an embolus (a small mass of material such as fat globules, air, clusters of bacteria, or even foreign matter such as a piece of metal from a bullet) or a thrombus (a blood clot)
inflammatory conditions - an inflammation within a blood vessel may occur as a result of trauma (physical trauma, such as from a fall, or chemical trauma, such as from an irritating medication being introduced into the vessel), infection, or an autoimmune disorder (e.g., polyarteritis, Raynaud's disease, and aortic arch syndrome)
varicose veins - occur when the veins of the circulatory system in the legs are exposed over time to pressure that causes stress on the walls and valves of the veins