From East Tennessee Medical News “Clinically Speaking”
With peripheral arterial and vascular disease affecting some 8 million Americans, imaging technology to evaluate blood flow and venous function has become an invaluable tool. Imaging methods such as Vascular Ultrasound, Magnetic Resonance Angiography (MRA), and Computed Tomographic (CT) Angiogram are increasingly used to screen, diagnose, and treat vascular issues.
Vascular ultrasound uses sound waves, not radiation, to produce real time images that show the structure and movement of blood flow throughout the body. Doppler ultrasound scans visualize blood flow through blood vessels and major arteries, enabling physicians to identify and pinpoint blockages, blood clots, and abnormalities. Ultrasound also aids physicians in planning effective treatment by assessing the size and condition of blood vessels.
As a non-invasive, inexpensive, and widely available technology, ultrasound has become a primary diagnostic tool. The fact that ultrasound equipment is often portable, and is a safe, painless test, makes it particularly valuable in screening at-risk patients for peripheral arterial, carotid disease, venous insufficiency, aneurysms, and a host of other vascular issues.
The future is bright for ultrasound as new advances in technology allow it to become a three-dimensional tool aiding in the diagnosis of vascular disease.
Despite its benefits, vascular ultrasound does have some limitations. Smaller and deeper vessels can be more difficult to evaluate and image with vascular ultrasound. In some cases, ultrasound cannot differentiate between an occluded blood vessel and one that is significantly narrowed. Calcifications may also obstruct the ultrasound beam. In those cases, other imaging tests such as Magnetic Resonance Angiography (MRA) or CT Angiogram may be necessary.
MRA is a non-invasive test that uses strong magnetic waves to produce detailed images of the vascular system. An MRA can show the location of a blocked blood vessel and the condition of the blood vessel walls. It is especially accurate for larger blood vessels. In some cases, MRA can provide information that can’t be obtained from an ultrasound or CT scan.
During the MRA procedure, the area of the body being imaged is placed inside a MRI machine. The narrow tunnel and long scan times can be problematic for obese patients or those with claustrophobia. Contrast dye may be used to increase visualization of blood vessels. While MRA is a safe and valuable procedure for studying blood vessels, it is more expensive than other imaging methods and may not be available in all medical facilities.
CT angiography is a minimally invasive test that uses x-ray beams to scan the body and produce detailed cross-section images of blood vessels and tissues. In most cases an iodine-rich contrast material is injected and used to highlight the area being studied. For patients with vascular disease, lower extremity CT angiography is especially effective at delivering precise detail in small blood vessels. It is also valuable in the work up and planning therapy of thoracic and abdominal aortic aneurysms.
Many vascular patients can undergo CT angiography instead of a traditional catheter angiogram. This method is quicker and more comfortable for most patients.
The CT angiography is also valuable in screening and detecting the narrowing or obstruction of blood vessels and venous disease before symptoms are present. Limitations include the slight risk of cancer from radiation exposure and possible reaction to the iodine-rich contrast dye.
As imaging technology continues to advance, with improved clarity that includes capabilities such as 3-D visuals, vascular patients will benefit from more accurate screening and diagnostic methods that lead to earlier treatment and better outcomes. The future of imaging is bound to enhance and make the future brighter for vascular patients.
George A. Pliagas, MD, FACS is a vascular surgeon with Premier Surgical Associates in Knoxville, Tennessee. He serves patient at Tennova Physicians Regional, Tennova North Knoxville Medical Centers, and the Premier Vascular Access & Imaging Center on Papermill Drive.