(Magnetic Resonance Angiogram, MRA)
What is an MRA?
You might be familiar with the testing procedure called magnetic resonance imaging (MRI). In this test, radio waves, a magnetic field, and a computer create a scan of your body parts to look for health problems.
Magnetic resonance angiography – also called a magnetic resonance angiogram or MRA – is a type of MRI that looks specifically at the body’s blood vessels. Unlike a traditional angiogram, which requires inserting a catheter into the body, magnetic resonance angiography is a far less invasive and less painful procedure.
During a magnetic resonance angiography, you lie flat inside the magnetic resonance imaging scanner, which is a large, tunnel-like tube that takes pictures of your body. In some cases, a special dye, known as contrast, may be added to your bloodstream to make your blood vessels easier to see. When needed, the contrast is administered with an intravenous (IV) needle.
What are the reasons for an MRA?
If your doctor believes that you may have a narrowing or blockage of blood vessels somewhere in your body, he or she may recommend a magnetic resonance angiography. Other conditions that your doctor can look for during this procedure include:
An aneurysm or weakness in the wall of an artery
A narrowing of the aorta, or aortic coarctation
Bleeding in and along the wall of the aorta, or aortic dissection
Evidence of stroke
Signs of heart disease
Narrowing or blockage of the vessels in the arms or legs
Renal artery stenosis, a narrowing of the blood vessels in the kidneys that can lead to high blood pressure and even renal failure
What are the risks of an MRA?
If a contrast is needed to make the blood vessels easier to see during the procedure, you may experience a bit of discomfort because of the insertion of the IV.
You might also experience some anxiety when placed inside the MRI scanner, which is a small, narrow space. If you think you might be claustrophobic, be sure to inform your doctor of this in advance. You may be given a mild sedative to make being in the MRI scanner more bearable.
Some potential risks of a magnetic resonance angiography include:
You may suffer bodily harm from having metal objects in pockets or clothing or metal implants (such as a pacemaker or bullet fragment) within your body. Before you undergo the procedure, you will be asked a series of detailed questions about any metal you may have in your body.
If you have a problem with your kidneys, you are at risk of developing a severe reaction after receiving the MRI contrast dye that is used to make blood vessels more visible. This reaction can affect tissues throughout the entire the body including the skin, joints, liver, and lungs. If you have a history of kidney disease, your doctor may decide that a contrast-enhanced MRI or MRA is not for you.
Women who are pregnant may experience additional risks in the MRI scanner. Make sure to tell your doctor if you are or might be pregnant.
You may be at risk for other complications, depending on your specific medical condition. Be sure to discuss any concerns with your doctor before the procedure.
How do I prepare for an MRA study?
EAT/DRINK: You may eat, drink and take medications as usual.
CLOTHING: You must completely change into a patient gown and lock up all personal belongings. A gown and locker will be provided for you. Please remove all piercings and leave all jewelry and valuables at home.
WHAT TO EXPECT: Imaging takes place inside of a large tube-like structure, open on both ends. You must lie perfectly still for quality images. The machine is very loud, so earplugs are required and will be provided to you.
CONTRAST: Your exam may include an injection of a contrast agent. A contrast agent is a special liquid that is injected through an intravenous (IV) line, a small tube placed in a vein. Some people may notice discomfort, tingling or warmth in the lips, metallic taste in the mouth, tingling in the arm, nausea or headache. These symptoms go away quickly.
ALLERGY: If you've had an allergic reaction to contrast that required medical treatment, contact your ordering physician to obtain the recommended prescription to take by mouth 24, 12 and two hours prior to the exam.
ANXIETY: If you require anti-anxiety medication due to claustrophobia, contact your ordering physician for a prescription. Please note, you will need someone to drive you home.
STRONG MAGNETIC ENVIRONMENT: If you have metal within your body that was not disclosed prior to your appointment, your study may be delayed, rescheduled or cancelled upon your arrival until further information can be obtained.
Your doctor may suggest additional preparation depending on your particular situation.
What happens during an MRA?
A magnetic resonance angiography may be performed on an outpatient basis or as part of a hospital stay. Generally, a magnetic resonance angiography follows this process:
You will be asked to remove any clothing, jewelry, eyeglasses, hearing aids, hairpins, removable dental work, or other objects that may interfere with the scan.
If you are asked to remove clothing, you will be given a gown to wear.
If you are to have a procedure done with contrast, an intravenous (IV) line will be started in the hand or arm for injection of the contrast dye.
You will lie on a scan table that slides into a large circular opening of the scanning machine. Pillows and straps may be used to prevent movement during the procedure.
The technologist will be in another room where the scanner controls are located. However, you will be in constant sight of the technologist through a window. Speakers inside the scanner will enable the technologist to communicate with and hear you. You will have a call button so that you can let the technologist know if you have any problems during the procedure. The technologist will be watching you at all times and will be in constant communication.
You will be given earplugs or a headset to wear to help block out the noise from the scanner. Some headsets may provide music for you to listen to.
During the scanning process, a clicking noise will sound as the magnetic field is created and pulses of radio waves are sent from the scanner.
It will be important for you to remain very still during the examination, as any movement could cause distortion and impact the quality of the scan.
At intervals, you may be instructed to hold your breath, or to not breath, for a few seconds depending on the body part being examined. You will then be told when you can breathe. You should not have to hold your breath for longer than a few seconds.
If contrast dye is used for your procedure, you may feel some effects when the dye is injected into the IV line. These effects include a flushing sensation or a feeling of coldness, a salty or metallic taste in the mouth, a brief headache, itching, nausea and/or vomiting. These effects usually last for a few moments.
You should notify the technologist if you feel any breathing difficulties, sweating, numbness or heart palpitations.
Once the scan is complete, the table will slide out of the scanner and you will be assisted off the table.
If an IV line was inserted for contrast administration, the line will be removed.
The full scan may take an hour or longer. This will depend on the type and number of blood vessels that your doctor wishes to examine.
What happens after an MRA?
You should move slowly when getting up from the scanner table to avoid any dizziness or lightheadedness from lying flat for the length of the procedure.
If any sedatives were taken for the procedure, you may be required to rest until the sedatives have worn off. You will also need to avoid driving.
If contrast dye is used during your procedure, you may be monitored for a period of time for any side effects or reactions to the contrast dye, such as itching, swelling, rash or difficulty breathing.
If you notice any pain, redness, and/or swelling at the IV site after you return home following your procedure, you should notify your doctor as this could indicate an infection or other type of reaction.
Otherwise, there is no special type of care required after an MRA. You may resume your usual diet and activities, unless your doctor advises you differently.
Your doctor may give you additional or alternate instructions after the procedure, depending on your particular situation.