MRA

A procedure that uses radio waves and a powerful magnet linked to a computer to create detailed pictures of the blood vessels and blood flow inside the body, a kind of MRI of the blood vessels. A contrast dye is sometimes injected into a vein to make the blood vessels and blood flow easier to see. MRA may be used to check for aneurysms (a bulge in the blood vessel wall) , blockages in the arteries, blood clots, and other blood vessel problems.

Other names

Also called magnetic resonance angiography.

Benefits

MRA is noninvasive, unlike traditional angiography.

Contra-indications / precautions

• Brain aneurysm clips
• Artificial heart valve
• Heart defibrillator or pacemaker
• Inner ear (cochlear) implants
• Insulin or chemotherapy port
• Intrauterine device (IUD)
• Kidney disease or dialysis (you may not be able to receive contrast)
• Neurostimulator
• Recently placed artificial joints
• Vascular stent

Worked with sheet metal in the past (you may need tests to check for metal pieces in your eyes) Because the MRI contains strong magnets, metal objects are not allowed into the room with the MRI scanner.

Things to avoid for MRI

• Pocketknives, pens, and eyeglasses
• Watches, credit cards, jewelry, and hearing aids
• Hairpins, metal zippers, pins, and similar items
• Removable dental implants

Abdominal Aorta MR Angiography

Uses

It is used to help diagnose: Arterial aneurysm (an abnormal widening or ballooning of a part of an artery due to weakness in the wall of the blood vessel) Aortic coarctation Aortic dissection Stroke Carotid artery disease Atherosclerosis of the arms or legs Heart disease, including congenital heart disease Mesenteric artery ischemia Renal artery stenosis (narrowing of the blood vessels in the kidneys)

MR angiography of bilateral internal carotid dissection

Risk of MRA

MRA is generally safe. It uses no radiation. To date, no side effects from the magnetic fields and radio waves have been reported.

Contrast used

The most common type of contrast used contains gadolinium.

Safety of contrast media

Allergic reactions to the substance rarely occur. Gadolinium can be harmful to people with kidney problems who require dialysis.

Alternative Names

MRA; Angiography - magnetic resonance

Efficacy of MRA

Head and Neck. Studies have proven that MRA is effective for evaluating flow in internal carotid vessels of the head and neck. However, not all potential applications of MRA have been proven effective.

MRA is used to evaluate the carotid arteries, the circle of Willis, the anterior, middle or posterior cerebral arteries, the vertebral or basilar arteries or the venous sinuses;

MRA is performed on patients with conditions of the head and neck for which surgery is anticipated and may be found to be appropriate based on the MRA. These conditions include, but are not limited to, tumor, aneurysms, vascular malformations, vascular occlusion or thrombosis. Within this broad category of disorders, medical necessity is the underlying determinant of the need for an MRA in specific diseases. MRA and contrast angiography (CA) are not expected to be performed on the same patient for diagnostic purposes prior to the application of anticipated therapy. Only one of these tests will be covered routinely unless the physician can demonstrate the medical need to perform both tests.

Peripheral Arteries of Lower Extremities. Studies have proven that MRA of peripheral arteries is useful in determining the presence and extent of peripheral vascular disease in lower extremities. This procedure is non-invasive and has been shown to find occult vessels in some patients for which those vessels were not apparent when CA was performed.

Menke's disease MR angiography showing hairpin like blood vessels

Abdomen. Studies have proven that MRA is considered a reliable diagnostic tool for the pre-operative evaluation of patients who will undergo elective abdominal aortic aneurysm (AAA) repair. In addition, scientific data has revealed that MRA is considered comparable to CA in determining the extent of AAA, as well as evaluation of aortoilliac occlusion disease and renal artery pathology that may be necessary in the surgical planning for AAA repair.

Chest. Diagnosis of Pulmonary Embolism. Current scientific data has shown that diagnostic pulmonary MRAs are improving due to recent developments such as faster imaging capabilities and gadolinium-enhancement. However, these advances in MRA are not significant enough to warrant replacement of pulmonary angiography in the diagnosis of pulmonary embolism for patients who have no contraindication to receiving intravenous iodinated contrast material.

Evaluation of Thoracic Aortic Dissection and Aneurysm. Studies have shown that MRA of the chest has a high level of diagnostic accuracy for pre-operative and post-operative evaluation of aortic dissection of aneurysm. Depending on the clinical presentation, MRA may be used as an alternative to other non-invasive imaging technologies, such as transesophageal echocardiography and CT.

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