Magnetic Resonance Imaging (MRI) is a diagnostic medical imaging technique. It uses a magnetic field and computer-generated radio waves to create clear and detailed images of almost every internal structure in the human body, including organs, bones, muscles, and blood vessels. It does not use X-rays (radiation).
The MRI process creates cross-sectional pictures, with each image a “slice” showing only a few layers of body tissue at a time. These pictures can then be examined on a computer monitor as 3D images that can be viewed from different angles.
What You Need To Tell Your Doctor
MRI scans use a powerful magnetic field that can be hazardous to patients with certain metallic implants. To ensure your safety, you’ll be asked some very specific questions before the test to prevent any harm to you.
How Does It Work?
MRI machines are large, cylindrical (tube-shaped) machines that create a strong magnetic field around a patient. Along with a radio-frequency, this magnetic field knocks the nuclei of hydrogen atoms in the body out of their normal position. As the nuclei realign back into proper position, they send out weak radio signals that a computer analyzes and converts into body images.
What To Expect
While older machines were narrow with tight head-to-ceiling space, newer machines offer improved patient comfort. They now are open on both ends with better interior lighting, improved head-to-ceiling room, more arm/body room, and are ventilated.
If you are anxious about the MRI process, talk to your doctor or technologist before the start of the examination. There many options that they have to help put you at ease and lower your stress if they know about your concerns ahead of time.
The MRI scanner makes very loud noises during certain parts of the exam. You will receive earplugs or headphones to make you more comfortable during the scan.
The scan usually takes between 15 to 90 minutes. Including the scan, the total examination time usually takes between 1.5 to 3 hours.