How MRI works

MRI, or magnetic resonance imaging, is a tool we use to image the brain while it is performing a cognitive task. This allows us to detect the location and magnitude of brain activity involved in the various types of cognitive functions we study. MRI allows us to view and record the changes in your brain activity during the time you are in the scanner.

Images are acquired using a combination of very powerful magnets and radio waves that alter the position of atoms in the body so that they reflect back a signal that is interpreted to show the composition of tissue (brain anatomy) or the amount of blood flow (brain activity).

These links explain this procedure in greater detail:

• Howstuffworks.com’s MRI explanation

• Cooperative Magnetic Imaging’s site for patients

Risks & Benefits

MRIs are non-invasive and do not involve any X-rays, radiation, or injections. Currently there are no known risks from exposure to the magnetic fields and radio waves used in Magnetic Resonance Imaging; however it is not assured that harmful effects will not be recognized in the future.  One known risk is that strong magnetic fields attract iron or steel metal objects, posing a safety risk. Prior to entering the scanner you will be given a questionnaire to determine if you have any foreign metal objects in your body such as a pacemaker, shrapnel, metal plate, etc. (see eligibility above). 

There is also a small risk of discomfort from claustrophobia, periods of immobility, and exposure to the noise of the magnet. To avoid these risks we screen people who are (or think they might be) claustrophobic, or would have trouble lying still on their back for 2 hours. In addition, all participants are required to wear ear plugs while inside the scanner.

Finally, as the magnet could potentially have an adverse effect on an unborn child, this research should not be undertaken if pregnant. Women of child-bearing age are required by the Duke Institutional Review Board to have a pregnancy blood test conducted within 72 hours prior to their scan. That test will be conducted at the Duke Clinics, and you will be paid an additional $10 for your time in getting the blood test.

The research will benefit our knowledge about the function of the human brain. In addition, you will be compensated for your participation time (see FAQs).