Pain management doctors use duplex ultrasound to observe how blood moves through blood vessels. The term “duplex” refers to the fact that duplex ultrasound uses both Doppler and conventional ultrasound imaging. Traditional ultrasound uses sound waves to create a picture of the blood vessels. In contrast, Doppler sound waves measure the speed and other aspects of blood flow.
In addition to measuring blood flow, doctors use duplex ultrasound in diagnosing a wide variety of conditions affecting the organs and soft tissues, including problems with muscles and the heart.
What Is Duplex Ultrasound?
In the early stages of ultrasound, doppler was used to measure the speed of blood flowing through blood vessels. Ultrasound waves were emitted, and the receiver picked up echoes that were translated into sounds. Depending on the pitch and pattern of the sound, the examiner could make out details such as velocity and heart rate. These machines are still available and used to measure fetal heart rate.
Duplex ultrasound, on the other hand, is used in modern ultrasound scanning machines. The modern scanner uses two kinds of ultrasound to help find vascular disease in the body. It is a noninvasive test that can show the anatomy of an organ as well as measure blood through blood vessels. Doctors have several names for duplex ultrasound tests, such as:
- Doppler Test
- Duplex Exam
- Ultrasound Exam
- Vascular Lab Test
How Does Duplex Ultrasound Work?
The transducer of an ultrasound machine emits sound waves at a frequency too high to be heard by the human ear. The process works with a transducer (similar to a microphone) that obtains an image of a blood vessel (or other soft tissue) that displays the direction and flow of the blood.
Placing the transducer on the skin allows ultrasound waves to move through the body to the organs and internal structures. When these sound waves hit an organ, they return to the transducer (like an echo). A computer converts the reflected waves into an image of the organs or tissues being examined. The computer translates the rate at which the sound waves return to the transducer (as well as how much of the sound wave returns) into an image of the body tissue it strikes.
Doppler ultrasound helps the doctor measure the speed and direction of blood flow in arteries and veins, as well as blood flow to an organ. Unlike a standard ultrasound, a “swishing” sound is audible from the Doppler ultrasound, which is the sound of the blood moving.
The procedure is painless, and typically lasts about 30 minutes; however, the duration varies depending on the structure being examined. Depending on the specific test, the position of the patient will also vary.
Duplex ultrasound has many advantages over other imaging methods.
- It is noninvasive.
- It is easily mobile.
- Patients tolerate it well.
- It can be performed on patients with implants.
Additionally, it does not expose the patient to possible kidney damage from the injection of a contrast dye (nephrotoxicity), or radiation.
Conditions Treated with Duplex Ultrasound
A duplex ultrasound is a first step in looking at arteries and veins and can help in diagnosing:
- Arteriosclerosis (thickening or hardening) of the arteries in the arms or legs.
- Venous reflux.
- Blood clots (deep vein thrombosis or DVT).
- Venous insufficiency.
The test can also be used to:
- Look at injury (trauma) to arteries or veins.
- Monitor arterial reconstruction and bypass grafts.
- Find narrowing blood vessels that may be causing leg pain when walking.
- Diagnose resting leg pain.
- Analyze foot, ankle, heel, or toe ulcers.
- Determine the reason for skin discoloration.
- Thrombophlebitis (an inflammation of the blood vessels that causes a blood clot to form and block one or more veins).
- Raynaud’s phenomenon (a spasm of small blood vessels that makes body parts feeling numb and cool, usually occurring in the fingers, toes, nose, and ears during low temperatures or when under stress.)
Duplex ultrasound can also be used in conjunction with other tests, such as the measurement of blood pressure in the legs, or when testing for reduced blood flow in the arms or legs.
The Advantages of Duplex Ultrasound
Using duplex ultrasound as a diagnostic procedure has several benefits:
- They are generally painless.
- They do not require needles, injections, or incisions.
- Patients aren’t exposed to ionizing radiation, making the procedure safer than X-rays and CT scans.
- Ultrasound captures images of soft tissues that don’t show up well on X-rays.
- Ultrasounds are widely accessible and less expensive than other methods.
Novus Spine & Pain Center
Novus Spine & Pain Center is in Lakeland, Florida, and treats patients with chronic pain with numerous therapies, including duplex ultrasound. By using a comprehensive approach and cutting-edge therapies, we work together with patients to restore function and regain an active lifestyle, while minimizing the need for opiates.
Duplex Ultrasound Resources
Doppler Ultrasound (Free Dictionary/Medical)
How is a duplex ultrasound used to diagnose deep vein thrombosis (DVT)? (WebMD)
What Is an Ultrasound? (WebMD)
Duplex Ultrasound (Medline Plus)
Doppler ultrasound exam of an arm or leg (Medline Plus)
Duplex Ultrasound (Society for Vascular Surgery)
Arterial Duplex Ultrasound – Legs (Cedars-Sinai)
Venous Duplex Ultrasound – Legs (Cedars-Sinai)
How Is Duplex Ultrasonography Performed? (College of Phlebology)
Ultrasound (Johns Hopkins)
Duplex Ultrasound (PubMed)
History of Ultrasonic Duplex Scanning (SAGE Journals)