An MRI scanner is a medical imaging machine that creates detailed pictures of the organs and tissues inside your body. It uses strong magnets, radio waves, and a computer. Unlike X-rays and CT scans, it does not use ionizing radiation.
How Does an MRI Scanner Work?
- Magnetic field: A powerful magnet lines up the protons in the water molecules of your body.
- Radio waves: The scanner sends short pulses of radio waves that knock the protons out of line. When the protons return to their place, they give off signals.
- Computer processing: The scanner picks up these signals, and a computer turns them into detailed cross-section images.
What Is an MRI Scanner Used For?
- Neurology: It shows the brain and spinal cord, which helps doctors diagnose tumors, stroke, and multiple sclerosis.
- Orthopedics: It shows joint injuries and soft tissue damage, such as torn ligaments.
- Cardiology: It helps doctors assess the heart and blood vessels.
- Abdomen and pelvis: It shows organs such as the liver, kidneys, and uterus.
What to Expect During an MRI
You lie on a table that slides into a tunnel-shaped machine. The scan usually takes 20 to 60 minutes. The machine makes loud knocking sounds, so staff give you earplugs or headphones. You need to lie very still.
MRI Safety Tips
- Tell your doctor if you have a pacemaker, metal implants, a cochlear implant, or metal fragments in your body, because the magnet can affect them.
- Remove jewelry, watches, and anything metal before the scan.
- Tell the staff if you feel nervous in small spaces. They can help you stay calm.
- Tell your doctor if you are pregnant.