What are they for?
Several types of imaging tests are used to obtain information about the condition of the vascular system. These can diagnose a range of conditions, including carotid artery disease, peripheral artery disease and abdominal aortic anyeurisms.
How are they done?
Ankle brachial index
The ankle brachial index measures blood pressure in the legs and compares it to the blood pressure in the arms. It can predict the severity of arterial disease in the legs.
Computed Tomography Angiography
Computed Tomography Angiography (CTA) can take pictures of a patient's blood vessels in a non-invasive way. In a CTA, X-rays are passed through part of the patient's body from several different angles while a dye is injected into the blood stream. Computers assemble the information into both two-dimensional and three-dimensional pictures. The procedure can detect narrowing, blockage or dilation of a blood vessel (aneurysm).
Pulse volume recording
Pulse volume recording, also known as plethysmography, is a painless, non-invasive test that measures blood flow within the arteries in order to help locate blockages. Pulse volume recording usually is performed on the arms and legs. It is done by placing three or four blood pressure cuffs on the area to be examined. These cuffs are connected to a pulse volume recorder, and each pulse appears as a waveform on a chart. The shape of these waveforms helps the physician diagnose possible blockages. These measurements are compared to each other, or in some cases, measurements taken before and after exercise will be compared.
Ultrasound can be used to examine blood flow through the major arteries and veins in the arms, legs and neck by using reflected sound waves. The test is a noninvasive way to determine where you might have blocked or reduced blood flow. A hand-held instrument (transducer) emits sound waves and records the echoing waves. When the transducer is pressed against your skin, it sends a stream of high-frequency sound waves into the body. As the sound waves bounce off internal organs, fluids and tissues, the microphone in the transducer records tiny changes in the sound's pitch. A computer then translates the sound waves into a real-time picture on a monitor.
Duplex imaging combines two different types of information gained by ultrasound. It displays pictures of structures within the body while showing blood flow to these structures. For example, duplex ultrasound imaging takes high-resolution pictures of the carotid arteries in the neck. It can detect narrowing or blockage of the blood vessels, which could limit blood flow to the brain. This imaging can be used to determine if a patient would benefit from surgery.