Patient education: Magnetic resonance angiography (The Basics)

What is magnetic resonance angiography? — Magnetic resonance angiography, or "MR angiography," is a procedure doctors do to look at blood vessels in the body. There are 2 main types of blood vessels: arteries and veins. These carry blood around the body.

There are 2 parts to MR angiography:

●First, a special dye called "contrast" is injected into a vein. This is done through a thin tube called an "IV." Sometimes, MR angiography can be done without the dye.

●Then, the doctor uses a type of imaging called "magnetic resonance imaging" on part of the body. The dye shows up on the images and shows how blood moves through your body.

MR angiography can show if there are problems with a blood vessel. For example, it can show if a vessel is blocked, damaged, enlarged, inflamed, or abnormal in other ways.

Your doctor might want you to have MR angiography:

●To check the blood vessels in your heart, kidneys, brain, lungs, intestines, limbs, or another part of your body

●Because you have symptoms of cardiovascular disease – "Cardio" means having to do with the heart. "Vascular" means having to do with blood vessels.

●To check for a blood clot or other blockage in a vessel

●To measure the size of blood vessels or other structures

●To find the source of bleeding inside your body

●To look at the soft tissues around the vessels to see if they are causing a blockage

●To help plan treatment

How do I prepare for MR angiography? — The doctor or nurse will tell you if you need to do anything special to prepare.

Before your procedure, your doctor will do an exam. They might send you to get tests, such as:

●Lab tests, including tests to check your kidney function

●X-rays – This is to check for any metal that might be in your body.

Your doctor will also ask you about your "health history." This involves asking you questions about any health problems you have or had in the past, past surgeries, and any medicines you take. Tell them about:

●Any medicines you are taking – This includes any prescription or "over-the-counter" medicines you use, plus any herbal supplements you take. It helps to write down and bring a list of any medicines you take, or bring a bag with all of your medicines with you.

●Any allergies you have

●Any bleeding problems you have – Certain medicines, including some herbs and supplements, can increase the risk of bleeding. Some health conditions also increase this risk.

●Any problems with your kidneys

●If you have trouble breathing when lying flat

●Any metal that might be in your body – This includes medical devices like pacemakers, stents, prosthetic joints, ear implants, or IUDs (a type of birth control). It also includes any hardware like pins, screws, metal plates, or staples that might have been used during a surgery, for example, to fix a broken bone. The MRI scanner uses a big magnet to create images. If you have metal in your body, your doctor will talk to you about whether it is safe to have MR angiography.

●If you get nervous in small spaces – Some machines are closed in. If small spaces make you feel nervous or anxious, tell your doctor. They can talk to you about what your machine will be like. They might be able to give you a type of medicine called a "sedative" to help you relax during the procedure.

You will also get information about:

●Taking your medicines – Your doctor or nurse might ask you not to take certain medicines before your procedure. If so, they will tell you when to stop taking them.

●What help you will need after your procedure – In some cases, you will need to have someone else bring you home.

Ask the doctor or nurse if you have questions or if there is anything you do not understand.

What happens during MR angiography? — When it is time for the procedure:

●You will change into a hospital gown and remove any metal objects from your body. These include jewelry, glasses, dentures, and hearing aids.

●You will get an "IV," which is a thin tube that goes into a vein. This can be used to give you fluids and medicines.

●You will get earplugs or headphones to wear – The machine is very loud, and the sound can damage your ears if you don't have ear protection.

●If your doctor prescribed medicines to help you relax, you will take them before the procedure starts. In some cases, you might get more medicines to make you feel sleepy.

●The person doing the procedure (called a "technologist") will use your IV to inject the contrast dye into your body, if you are getting it. You might feel cold at the place where it is injected. You might also feel nauseous or dizzy, or get a headache.

●You will lie on the narrow table of the MRI machine (figure 1). The table slides into the scanner. Some MRI machines look like a long tube. Others are more open.

●There will be a speaker so you can talk to the technologist from inside the scanner. The technologist will be in another room.

●You need to lie very still during the MRI scan so that the images are clear. You might also be asked to do other things, like hold your breath for a few seconds. This depends on which part of your body is being scanned.

●The technologist will start scanning.

●Once the procedure is over, the table will slide back out of the machine, and your IV will be removed.

What happens after MR angiography? — This depends on whether you were given medicines to help you relax. If you did not get any medicines to help you relax, you can usually go home right away.

●If you had medicines to help you relax, you will be moved to a "recovery room" after your procedure. These medicines can make you sleepy. The staff will watch you closely as your medicine wears off. You might need someone else to bring you home after your procedure.

●If you were given contrast dye, drink plenty of fluids for a few days. This helps to clear the dye from your system.

What are the risks of MR angiography? — Your doctor will talk to you about all of the possible risks, and answer your questions. Possible risks include a minor or serious allergic reaction to the dye.

What else should I know? — You might get your results the same day, or it might take a little longer for them to be read by an expert. Your doctor or nurse will let you know when to expect your results.

If your MR angiography shows any abnormal results, your doctor or nurse will talk to you about what to do next.

More on this topic

Patient education: MRI scan (The Basics)
Patient education: Angiography (The Basics)
Patient education: Computed tomographic angiography (The Basics)