- Risks and Complications
What is Magnetic Resonance Imaging (MRI)?
Magnetic resonance imaging (MRI) is a procedure used to diagnose and evaluate diseases and injuries. Magnetic resonance imaging scans use large, powerful magnets and a specialized computer to produce high-resolution pictures cross-sectional images of the bones and soft tissues. Unlike X-rays and computerized tomography (CT) scans, MRI works without radiation.
What is Magnetic Resonance Imaging (MRI) Used For?
Magnetic resonance imaging (MRI) scans are often used to image the non-bony parts or soft tissues of the body such as the:
- Spinal cord and nerves
- Heart and blood vessels
- Internal organs
- Bones and joints
How do Doctors Perform Magnetic Resonance Imaging (MRI)?
Prior to an MRI exam, patients are asked remove metals and other objects that might affect the magnetic imaging, such as:
- Hearing aids
- Underwire bras
- Cosmetics that contain metal particles
- Hair accessories
During an MRI exam, a patient typically lies on a table that slides into the tube-shaped MRI scanner, which is the bore of the magnet, for imaging.
An electric current is passed through coiled wires to create a magnetic field in a patient’s body in the area of the body to be imaged. Radio waves are used to cause the tissues to vibrate and create digital images of the scanned area of the body. A computer records the rate at which the body part emits the vibrations, and then translates the data into a two-dimensional picture. During the exam, the patient is able to communicate with a technologist who is in another room.
In some cases, intravenous (IV) gadolinium-based contrast agents (GBCAs) are used to enhance the contrast and detail of the images.
MRIs are not painful but they can be quite noisy, with a lot of tapping or thumping noises, so earplugs or headphones are often used to muffle the sound.
A typical MRI scan lasts from 20 to 90 minutes, depending on the part of the body being imaged.
What are Risks and Complications of Magnetic Resonance Imaging (MRI)?
There are not many complications or side effects of magnetic resonance imaging (MRI), however, there are some considerations:
- Implanted devices and foreign bodies
- People who have pacemakers, vagus nerve stimulators, implantable cardioverter-defibrillators, loop recorders, insulin pumps, cochlear implants, deep brain stimulators, and capsules from capsule endoscopy should not get an MRI
- Unstable patients
- May not be able to tolerate an MRI
- It is recommended MRI scans be avoided, especially in the first trimester
- Gadolinium contrast agent
- Patients who require dialysis may have a severe reaction to use of these agents
- Claustrophobic patients
- These patients may require sedation or may need to have an open MRI
- Agitated patients
- Young children or anyone who is unable to stay still may need to be sedated
- Obese or large patients
- Patients may be unable to fit into the cylinder of the MRI system
- These patients may be able to be accommodated in an open MRI
- MRI machines can be very noisy and ear protection may be needed