The use of various imaging technologies to visualize the blood vessels for diagnosis and medical procedures is referred to as vascular imaging. Since the first image of the artery was viewed in 1929 using x-ray technology, science has drastically improved on the technology and developed ways to capture three-dimensional (3D) and real-time vascular images. There are essentially four types of vascular imaging used with medical facilities today: arteriogram, ultrasound, magnetic resonance (MR) angiography, and computed tomography (CT) angiography. Each has distinct advantages and disadvantages, which is why they are specialized towards various procedures.
Arteriogram utilizes x-ray technology and a contrast dye injected into an artery to obtain visible images. This procedure delivers very high-level resolution images of the arteries for comparative sizing and placing stints when necessary. The data can also be stored as a digital file, making it portable and convenient to archive, which is a large reason why this type of vascular imaging has become so popular in limited uses. Exposure to radiation remains the major disadvantage of this vascular imaging technique.
Instead of radiation, ultrasound equipment uses sound waves, making it a much safer procedure for both patients and medical professionals. Besides the benefit of viewing images in real time, it also captures the speed and direction of blood flow throughout the arteries and veins, as well as the pumping and pulsing of blood vessels. Ultrasound has gained popularity because it is portable, less expensive than other methods, and offers less overall discomfort to patients. Its drawback, however, within the vascular imaging category is that the procedure is heavily operator-dependent, meaning that only trained professionals can effectively use the equipment.
Like ultrasound, MR angiography is not an x-ray procedure; instead, it uses magnetic waves to create a picture of the patient’s anatomy. An advantage of this modality over other methods is that through its time-dissolve MR angiography, multiple 3-D data images may be taken, allowing a more accurate study of a specific area of interest during a time run. Unfortunately, this procedure is unsafe for patients with pacemaker and/or surgical clips. MR angiography is also more difficult to perform compared to the other types of vascular imaging.
In contrast, CT angiography offers simplistic operation while taking as many as 64-slice views over 20 to 30 seconds with very high-resolution images. For this reason, CT scanners are now common in emergency rooms where speed and resolution are critical in diagnosing multiple trauma cases. CT angiography’s unique advantage over the other vascular imaging technologies is its capacity for capturing, in one view, real-time 3-D images of flowing blood in the entire vascular system. Its downside, like with arteriogram, is its use of radiation and the dangers of long-term exposure.