What is MRI?

MRI stands for Magnetic Resonance (a fancy word for echo) Imaging. MRI is a safe and painless test that uses large magnets and radio waves to produce detailed pictures of almost any part of the body. Unlike other tests, such as CT and X-ray, it doesn’t use radiation to see inside your body.

Doctors use MRI to look inside a patient’s body to check for any illnesses. The quicker they are able to make the diagnosis, the sooner they can start treating the patient, especially if the illness is life threatening.

Athletes also benefit from MRI to take a closer look at their injuries. By diagnosing what is wrong, the quicker they can rehabilitate their injury and get back to training.

How does the MRI machine work?For an MRI scan, the patient is placed on a table that slides into a tunnel. When inside the tunnel, all the patient needs to do is stay perfectly still and let the MRI machine do all the work.

MRI technology relies on hydrogen atoms that are found in water. As the human body is made up of around 75% water, MRI is perfect for looking inside the human body as it contains millions of tiny hydrogen atoms (so small, they are invisible to the human eye).

During the examination, the large doughnut-shaped magnets that surround the tunnel are turned on, making all the tiny hydrogen atoms point in the same direction. Pulses of radio waves are then sent through the body, rocking the atoms back and forth. As the atoms relax, they release energy signals that are picked up by a powerful antenna connected to the computer. Different tissues (such as muscles, organs, nerves and bones) release different energy signals, so the computer is then able to form a detailedpicture of the inside of the body by showing dense tissues as white and less dense tissues as black.

To find out more about MRI have a look at the GE healthcare website which includes a great video to help you understand the basics of MRI.

If you still want to find out more, have a look at the NHS choices website for further information.

The images within this article were kindly provided by GE Healthcare.


If you would like to work in this area, you could be:

  • doctor – diagnosing and treating illness, disease or infection in patients admitted into hospital or outpatient clinics
  • radiation and protection officer – checking the intensity of X rays and of X ray equipment throughout the hospital to ensure safety
  • nurse – concerned with nursing sick and injured patients back to health in both community or hospital settings
  • clinical photographer – providing a wide range of photography services to all staff working in medical and paramedical areas
  • radiographer – producing high quality images used in the diagnosis of injury and disease
  • An MRI specialist – researching and providing clinical support and advice for patients having scans