Magnetic resonance imaging (MRI) is an imaging test that allows doctors to look at the inside of the body. The test may be done to check for medical problems such as tumors, heart or blood vessel trouble, uterine fibroids or problems affecting the abdominal organs (such as the liver), small intestine, colon, rectum or urinary tract.
MRI may also be done to check on the development of an unborn baby.
Whatever the reason you need an MRI, when you choose Stanford Health Care - ValleyCare you can be sure that you're receiving the best possible care using the latest technology.
We have been certified by the American College of Radiology.
How an MRI Scan Works
An MRI uses a combination of a large magnet, radiofrequency waves and a computer to produce detailed images of organs and structures inside the body. The scan creates two-dimensional images of a body structure or organ. Cross-sectional views can also be obtained to reveal further details.
MRI may be used instead of computed tomography (CT) in situations where organs or soft tissue are being studied, because bones do not obscure the images of organs and soft tissues, as they do in CT.
Unlike CT scans or x-rays, MRI doesn't use radiation.
Due to the use of the strong magnet, MRI cannot be performed on patients with implanted pacemakers, intracranial aneurysm clips, cochlear implants, certain prosthetic devices implanted drug infusion pumps, neurostimulators, bone-growth stimulators, certain intrauterine contraceptive devices, or any other type of iron-based metal implants. In addition, MRI may not be used with internal metallic objects such as bullets or shrapnel, as well as surgical clips, pins, plates, screws, metal sutures or wire mesh.
What to Expect During an MRI
An MRI may be performed on an outpatient basis or as part of inpatient care. Although each facility may have specific protocols in place, generally, an MRI procedure follows this process:
- Because of the strong magnetic field, you must remove all jewelry and metal objects, such as hairpins or barrettes, hearing aids, eyeglasses and dental pieces.
- If a contrast medication and/or sedative is to be given by an intravenous line (IV), an IV line will be started in your hand or arm. If the contrast is to be taken by mouth, you will be given the contrast to swallow.
- You will lie on a table that slides into a tunnel in the scanner. It is important that you remain very still during the examination.
- The MRI staff will be in another room where the scanner controls are located. However, you will be in constant sight of the staff through a window. Speakers inside the scanner will enable the staff to communicate with you. You also have a call bell to let the staff know if you are having any problems during the procedure.
- 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. You may be given headphones to wear to help block out the noises from the MRI scanner and hear any messages or instructions from the technologist.
- At intervals, you may be instructed to hold your breath for a few seconds, depending on the body part being examined. You should not have to hold your breath longer than a few seconds, so this should not be uncomfortable.
Before the test begins tell the radiologist if any of the following apply to you:
- You are claustrophobic and think that you will be unable to lie still while inside the scanning machine.
- You have a pacemaker inserted or have had heart valves replaced.
- You have metal plates, pins, metal implants, surgical staples or aneurysm clips.
- You have permanent eye liner.
- You are pregnant.
- You have had a bullet wound.
- You have worked with metal (i.e., a metal grinder).