Magnetic Resonance Imaging (MRI)

What is a MRI scan?

Magnetic resonance imaging (MRI) is a noninvasive imaging exam that uses a strong magnetic field to provide images of internal organs and tissues. Doctors who specialize in imaging are called radiologists and they will analyze and interpret your images.

How is MRI different than CT or X-ray?

MRI does not use radiation, as do X-rays or CT scans. MRI machines use magnets and radio waves to make images of the human body.

What are the benefits of MRI?

MRI provides more sensitive images of anatomy inside the human body. The level of detail is extraordinary compared with any other imaging technique. MRI is the method of choice for the diagnosis of many types of injuries and conditions because of the incredible ability to tailor the exam to the particular medical question being asked.

What are the risks of MRI?

There are no known biological risks to humans from being exposed to magnetic fields of the strength used in medical imaging today. Therefore, the MRI exam poses almost no risk to the average patient when appropriate safety guidelines are followed. The strong magnetic field used in MRI is not harmful in itself, but medical devices that contain metal may malfunction or be a hazard during an MRI. You will be screened to ensure your safety.

What is MRI contrast and what are the risks?

MRI contrast is a special medication that is used to improve visualization of certain diseases. If necessary, it is administered through a small IV catheter, which is placed in a vein in your arm prior to the procedure. The contrast provides important details about the blood vessels and organs inside the body. Rare risks include:

  • Allergic reactions from the MRI contrast occur in less than 1 percent of all patients. By far the most common reactions are nausea, headache, hives and vomiting. These reactions are usually mild and can easily be controlled with medication. Please tell the technologist if you know you are allergic.
  • Nephrogenic systemic fibrosis (NSF) is a disorder that is believed to be caused by the injection of high doses of MRI contrast in patients with poor kidney function. To date, there is no evidence that other patient groups are at risk. Please tell the technologist if you have kidney disease.

    How can the risks of MRI contrast be reduced?

    Prior to your MRI examination you will be asked to complete a MRI screening form to determine if you have any risk factors that may place you at high risk for this study. It is important for your own safety that you complete this form as accurately as possible. In addition, laboratory tests to check kidney function will be evaluated by the MRI staff to minimize the susceptibility for NSF. Your case will be reviewed by the radiologist and/or your doctors should an alternative approach to the procedure protocol be required.

    Are there alternatives to MRI?

    Although MRI defines detail differently than other imaging modalities, on occasion alternative tests can be performed. These include CT, bone scan, arthrography, and ultrasound.

    What if I might be pregnant?

    There have been very few research studies determining the relative safety of using MR procedures in pregnant patients. The decision of whether or not to scan a pregnant patient is made on a case-by-case basis with consultation between the MRI radiologist and the patient's physician. The benefit of performing the scan must outweigh the risk, however small, to the fetus and mother.