Information on MRI Scans

Magnetic resonance imaging (MRI) is a diagnostic medical test using a specialized machine and equipment to create images of the body. According to the International Society for Magnetic Resonance in Medicine (ISMRM), an MRI is considered safe and non-invasive. The test does not use radiation and may be done instead of or as an addition to a CT scan.

• The MRI scanner is a tube like machine.

Facts

• During an MRI scan a strong magnetic field is created around the patient by the machine. Radio waves are then omitted from the scanner. The magnetic field, together with the radio waves, changes the alignment of hydrogen atoms in the body. With the use of a computer, two-dimensional pictures of the body are created, according to the movement of the hydrogen atoms.

Function

• According to the Mayo Clinic, an MRI can be performed on various organs in the body, such as the liver, kidneys, lungs and pancreas. It is used to determine the presence of abnormalities, such as tumors. A brain MRI may be recommended to help diagnose conditions, such as an aneurysm, tumor or a stroke. Structural problems with the heart may also be able to be identified with an MRI of the heart and blood vessels.

Procedure

• Because the magnetic field and radio waves used to form images cannot be felt, the procedure is painless. However, some people may become uncomfortable lying still for the length of the scan. The patient lies on a table which slides into the scanner. Occasional noises will be heard by the patient once the scan starts. The noise is the pulsing of the radio waves being created by the machine. The technician will be running the scan from a control room, but is able to communicate with the patient during the test through a speaker in the machine. Some patients may be instructed to hold their breath occasionally during the test.

Precautions

• Because there is a strong magnetic field used during an MRI, certain precautions are needed. People who have a pacemaker or defibrillator implanted into their chest should not undergo an MRI, because it can interfere with the devices. Patients should take off any jewelry which contains metal. The strong magnetic field can pull objects forcefully toward the machine, which can cause injury if a person is wearing metal. According to ISMRM, pregnant or nursing patients should consult with their doctor prior to going for an MRI scan.

Considerations

• The length of time it takes to complete an MRI may vary depending on what part or parts of the body are being scanned. However, according to Cedar Sinai Hospital. most scans take 30 to 90 minutes. Some patients who are claustrophobic or young children may need sedation during the test, in order to be still for the entire exam.