Magnetic Resonance Angiography (MRA) is a specialized diagnostic imaging test that creates detailed pictures of the body’s blood vessels and blood flow. Like a standard Magnetic Resonance Imaging (MRI) scan, MRA uses a powerful magnetic field and radio waves to generate images. The key difference is that MRA employs specific techniques to focus on the vasculature, rather than the surrounding soft tissues or organs. This non-invasive procedure allows healthcare providers to assess the condition of arteries and veins without the need for traditional, more invasive catheter-based methods.
The Function of Magnetic Resonance Angiography
The primary purpose of an MRA is to visualize the flow and structure of blood vessels throughout the body, often creating three-dimensional images. This allows clinicians to identify and evaluate various vascular conditions in areas like the brain, neck, heart, kidneys, and limbs. MRA is particularly effective for detecting abnormalities that affect blood circulation.
It is frequently used to look for aneurysms, which are abnormal bulges in a vessel wall that carry a risk of rupture. MRA can also identify stenosis (the narrowing of an artery) or occlusions (complete blockages) caused by conditions like atherosclerosis or blood clots. The detailed images help physicians monitor known vascular diseases and plan necessary treatments or surgical interventions. This detailed visualization is often necessary when evaluating conditions such as carotid artery disease or renal artery stenosis.
Preparing for the Scan
Preparation for an MRA test centers on safety due to the powerful magnetic field used by the scanner. Patients must remove all external metal objects before entering the scanning room, including jewelry, hairpins, watches, keys, and any clothing with metallic fasteners. Credit cards and hearing aids must also be secured outside the room, as the magnetic field can damage them.
A mandatory safety screening requires you to disclose any internal metallic devices or foreign objects. Items such as pacemakers, certain intracranial aneurysm clips, inner ear implants, and some surgical staples are sensitive to the magnetic field. These devices can pose a safety hazard or cause image distortion, and in some cases, may mean the test cannot be performed.
Many MRA procedures require the injection of a Gadolinium-based contrast agent through an intravenous (IV) line to make the blood vessels show up more distinctly. This contrast material improves the clarity of the vascular structures. Because the kidneys filter this agent out of the body, you must inform your healthcare provider if you have any history of kidney disease or dialysis.
You will generally be asked to change into a hospital gown to ensure no metal is present on your clothing. Follow any guidance provided by the facility regarding eating or drinking before the test, especially if a contrast agent is planned. If you experience anxiety in enclosed spaces, discuss this with your physician beforehand, as a mild sedative may be suggested to help you remain comfortable and still during the procedure.
The Patient Experience During the Test
Once preparation is complete, you will lie on a narrow table that slides into the large, tube-like MRA scanner. The total duration of the scan typically ranges from 30 to 90 minutes, depending on the area being imaged and the complexity of the study. Remaining perfectly still throughout the entire procedure is necessary, as any movement can blur the images and compromise the diagnostic quality of the scan.
During the imaging process, you will hear loud, repetitive knocking, clicking, or banging noises as the machine’s internal magnets rapidly turn on and off. You will be provided with earplugs or headphones to protect your hearing. The technologist operates the machine from an adjacent room, but a two-way intercom system allows for continuous communication. You may also be given a call button to press if you feel any discomfort or have an urgent concern. After the scan is finished, you will be free to resume your normal activities unless you received a sedative. The collected images are then interpreted by a specialized radiologist, who sends a report to the ordering physician.