MRI and MRA Scan
What are MRI and MRA?
“MRI” stands for magnetic (mag-NET-ik) resonance (REZ-oh-nentz) imaging. MRI uses magnetic fields and radio waves to make pictures of the body without using x-rays. The pictures, called scans, are 3-dimensional and are shown on a screen.
MRI lets doctors see very detailed images of the inside of your body. MRI passes through bone and takes pictures of soft tissue, such as tendons, blood vessels, and the brain.
“MRA” stands for magnetic resonance angiography (AN-jee-OG-ruff-ee). An MRA scan gives a view of specific blood vessels (arteries and veins). MRA may be included with an MRI exam.
The checklist below helps to show if you can have MRI and MRA. The magnetic fields used are extremely powerful, so it’s very important
that we know about any metal in your body. Many items listed below are safe, but some mean that you cannot have MRI or MRA.
Check all the items that apply to you:
- Have a history of working with metal
- Have metal in your eye or have ever had metal removed from your eye
- Have shrapnel, BBs, or bullets anywhere in your body
- Have a pacemaker, cardioverter, or defibrillator have aneurysm clips
- Have embolization coil
- Have had heart valve replacement or cardiac stents
- Have hearing devices of any kind
- Have implants of any kind (for example, dental, breast, penile, or ear)
- Have had surgery in the past 2 months
- Have fear of tight or enclosed spaces (claustrophobia)
- Think you may be pregnant
- Have had problems with past MRI or MRA
If you checked any of these items, call and tell your testing center before the day of your MRI exam. Do not assume that your doctor’s office knows about your metal implants or any other item. You are responsible to alert us to these items.
How do I prepare for the test?
For an MRI exam, no special preparation is needed. On the day of the MRI, you may eat or drink fluids, go about your normal activities, and take your routine medicines, unless your doctor says otherwise. For an MRA exam, your testing center will tell you about any special preparation needed.
If the area of your body being tested is above the shoulder, do not wear any makeup, jewelry, hair pins, or hair products such as mousse, gel, or hair spray. These items may affect the scan.
Tell the doctor or technologist if you’ve ever had an allergic reaction to a contrast enhancing agent, shellfish, or iodine, or if you have asthma.
What happens before the test?
Plan to arrive 30 minutes before your scheduled exam time to register. You may be asked to change into a hospital gown and pants. If so, you must remove all jewelry and store personal belongings in a locker. It’s best to leave all valuables at home.
For some MRI and MRA exams, a contrast enhancing agent is used. If you are to receive an enhancing agent, an intravenous line (IV) will be inserted in your arm or hand. The enhancing agent may give you a brief sensation that moves up your arm. You may get a warm, flushed feeling; a taste of salt or metal in your mouth; or nausea for a few minutes. This is normal, but you should tell the technologist about these or other reactions.
What happens during the test?
Most MRI and MRA exams are done inside a closed scanner. The magnet is like a tunnel, open at both ends, allowing light and air inside.
If you are large or have a fear of enclosed spaces (claustrophobia), please tell your doctor in advance so arrangements can be made.
The technologist will help you onto a scanning bed. You will lie flat on the bed. The scanning bed will move into the center of the magnet. Inside the scanner, you should lie quietly, breathe normally, and relax. You must stay as still as possible, so the pictures are clear. You’ll have ear plugs to block out the machine’s loud knocking noise.
The technologist will be in a room behind a large window and will see and hear you at all times. You’ll be able to talk through an intercom. The exam usually lasts 1 to 2 hours.
What happens after the test?
The technologist will help you off the bed. You may resume your normal diet. If an enhancing agent was used, drink plenty of fluids to flush the agent out of your body. If you have diarrhea for more than a day, call your doctor.
How do I get my test results?
A doctor who is a radiologist will study your scans and report the results to your doctor. Your doctor will discuss the results with you. Ask your doctor or testing center about how to get your test results.