Similar to magnetic resonance imaging (MRI), an MRA is a test that allows the doctor to view inside the body, and more specifically, to review the condition of your blood vessels.
The test results reveal details that will help your doctor make an accurate diagnosis of your condition, and to determine a customized treatment regimen.
An MRI and an MRA are actually the same test. The only difference is the application of the technology. Unlike X-rays, which use ionizing radiation to create medical images, both the MRI and MRA use powerful magnets and radio waves to create images of the inside of the body.
In many cases, the MRA provides information that a doctor cannot detect in an ultrasound, regular X-ray, or CT (computed tomography) scan. The exam is also noninvasive, and the images may be stored on computer or printed on film.
The difference between an MRI and an MRA is that an MRA is used specifically to examine blood vessels. An MRI is performed to examine other parts of the body including the abdomen, chest, pelvis and internal organs.
The "A" in MRA stands for "angiography." This term describes any medical test that looks at the inside of blood vessels, including veins and arteries. When blood vessels become blocked, narrowed, or otherwise damaged, they can lead to problems like chest pain, heart attack, and stroke. An MRA allows the doctor to find exactly which blood vessels are injured, and the extent of the damage.
Your doctor may schedule an MRA exam if you have suffered any of the following:
- heart disease, including congenital heart disease
- inflammation of blood vessels (vasculitis)
- swelling of the aorta, the main artery of the body (arterial aneurysm)
- narrowing of the aorta
- artery narrowing in the arms or legs (atherosclerosis)
- narrowing of the blood vessels in the kidneys (renal artery stenosis)
- narrowing of the blood vessels that lead to the brain (carotid artery disease)
- narrowing of one of the three arteries that supply the small and large intestines (mesenteric artery ischemia)
An MRA may also be used to guide surgeons in making repairs to diseased blood vessels, to evaluate arteries feeding a tumor prior to surgery or radiation therapy, and to screen individuals for arterial disease.
Before the test, your doctor will likely instruct you not to eat or drink anything for 4 to 6 hours. If you are pregnant, have a pacemaker or other metallic device in your body (like an artificial heart valve), or weigh more than 300 pounds, you may not be eligible for the MRA.
Once you are ready for the exam, you may be instructed to change into a hospital gown and remove any metal objects or jewelry that may interfere with the magnetic field. If you’re nervous or claustrophobic, you may be given a sedative to help you relax. You’ll want to lie as still as you can during the test to create the best quality images.
Next, the technician may inject a contrast dye into your hand or forearm to help improve the quality of the images, but you can take the exam without the dye as well. Be sure to inform your doctor if you have any concerns about allergic reactions to the dye, or if you have kidney disease or were a victim of prior kidney failure. Poor kidney function can affect your ability to flush the dye from your system.
Finally, you simply lie on the table which will slide through a doughnut-shaped chamber. Inside the chamber, the magnetic fields and radio waves surround your body and create the images, but you will feel no effects. The procedure is entirely painless, and may last anywhere from 30 to 90 minutes. You’ll be able to talk to the technician through a speaker, and you will also likely be provided with ear plugs or ear phones to help you relax.
MRAs are extremely safe. Since they don’t use radiation like X-rays do, they can be performed repeatedly without concern of risks. The only complications you’ll want to be aware of are those related to the dye and the sedatives.
You may experience nausea, flushing, a warm sensation, or a headache from the dye, which is normal and should pass. If you experience itching or shortness of breath, tell the doctor right away as that could indicate an allergic reaction. Also, if you are sedated for the procedure, be sure to arrange a ride home as you should avoid driving.