Introduction to Vascular Ultrasound
An upper extremity ultrasound is a type of vascular ultrasound exam. Vascular ultrasound is an imaging technique designed to examine the cardiovascular, or circulatory system, which comprises the veins and arteries. These ultrasound exams use Doppler technology, which uses harmless, high-frequency soundwaves to create images and videos of what is happening inside the body.
An upper extremity ultrasound focuses on the veins and arteries within the upper extremities or arms. A full upper extremity ultrasound examines the veins branching off the brachiocephalic artery on the left and the aortic arch on the right side. These include the subclavian and axillary veins.
Uses for Upper Extremity Venous Ultrasound
Upper extremity arterial ultrasound exams are often used to help diagnose deep vein thrombosis or DVT. DVT occurs when a blood clot forms within the veins. Without proper treatment, a portion of the blood clot can break off, travel through the bloodstream, and become lodged in the lungs. This is called a pulmonary embolism (PE), and it can be fatal.
An upper extremity venous ultrasound is also used for vein mapping to inform the placement of a graft or stent and monitor them post-surgery. These ultrasounds can also be an important tool for dialysis patients. Patients with kidney failure often need to undergo dialysis treatment. Part of this process includes a procedure called an arteriovenous (AV) fistula. This procedure connects an artery and vein within the arm to be used as an access point for dialysis.
An upper extremity ultrasound is used for the vein mapping process. The Doppler technology creates a map from the images of the veins and arteries for surgeons to use to decide which vein and artery should be connected for the AV fistula. In this case, the exam process often includes a duplex ultrasound, which shows images of the tissues surrounding the veins and arteries.
Ultrasound Exam Process
A physician may refer a patient for an upper extremity arterial ultrasound exam if they feel the patient is exhibiting symptoms of DVT or if vein mapping is needed. Registered Vascular Technologists (RVTs) often perform these venous Doppler ultrasound exams. RVTs are specially trained and certified to conduct vascular ultrasound exams. Below is an example of a typical ultrasound exam:
- The ultrasound machine consists of three major components: a video monitor, a console, and a handheld device called a transducer. The transducer emits harmless, high-frequency soundwaves that create images and videos of what is happening inside the body.
- The RVT may ask the patient to lie down, depending on the area being examined. They will apply a gel to the transducer, which helps to eliminate air pockets once it comes into contact with the skin. This helps the soundwaves to travel better.
- The RVT will use the transducer to gently compress the skin and thereby compress the veins and arteries beneath while looking at the images on the video monitor. The Doppler technology also shows the speed and direction of blood flow, all of which can help identify if there is a blood clot in the case of DVT.
- The resulting images and videos are sent to an interpreting physician, and then to the referring physician for final review and diagnosis.
An upper extremity ultrasound is an invaluable diagnostic tool, especially since it is harmless and noninvasive. Upper extremity arterial ultrasounds focus specifically on the veins and arteries of the arms. They are used for vein mapping, monitoring the veins and arteries post-surgery, and diagnosing potentially serious conditions such as DVT.
Guest Contributor: Jordan Galerkin
Sources:
- Venous Extremity Ultrasound. Cleveland Clinic. https://my.clevelandclinic.org/health/diagnostics/15765-upper-or-lower-venous-extremity-ultrasound
- DVT Upper Extremity Ultrasound. University of Texas Southwestern Medical Center. https://www.utsouthwestern.edu/education/medical-school/departments/radiology/protocols/assets/US DVT Upper Extremity.pdf
- Preparing for Dialysis. Yale Medicine. https://www.yalemedicine.org/conditions/preparing-dialysis-av-fistula
- Venous Ultrasound. Radiology Info. https://www.radiologyinfo.org/en/info/venousus
