Plethysmography is used to measure changes in volume in different parts of the body. The test may be done to check for blood clots in the arms and legs, or to measure how much air you can hold in your lungs.
Penile pulse volume recording is a type of this test that is done on the penis to check for causes of erectile dysfunction.
Most commonly, plethysmography is performed to check blood flow in the arteries of the legs. This is done in people with conditions like hardening of the arteries (atherosclerosis) that causes pain during exercise or poor healing of leg wounds.
You will lie down on a bed or stretcher for about 20 minutes.
Several blood pressure cuffs will be placed above and below the knee on both of your legs.
A computer will measure the volume of blood in your leg before and after the cuffs are inflated.
How to Prepare for the Test
You will be given a hospital gown or other loose clothing to wear during the test.
How the Test will Feel
The blood pressure cuffs may feel tight on your legs and cause mild discomfort.
Why the Test is Performed
Narrowed arteries due to vascular disease can cut down on blood flow. This can lead to pain in the legs during exercise (claudication).
When the problem is severe, it can cause poor healing of wounds on the feet, infections, or gangrene. This study is performed to see if the blood flow is normal. Most often it is combined with Doppler measurements, blood pressure measurements, and ankle-brachial index (ABI).
This test is not as effective in people who are obese.
Unlike standard pressure measurements, this test can be used even if there is a high degree of hardening of the arteries.
Fowler GC, Reddy B. Noninvasive Venous and Arterial Studies of the Lower Extremities. In: Pfenninger JL, Fowlder GC, eds. Pfenninger & Fowler's Procedures for Primary Care. 3rd ed. Philadelphia, PA: Elsevier Mosby; 2011:chap 88.
Jason Levy, MD, Northside Radiology Associates, Atlanta, GA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.