Primarily a noninvasive medical imaging technique used in radiology to visualize detailed internal structure and limited function of the body. MRI provides much greater contrast between the different soft tissues of the body than computed tomography (CT) does, making it especially useful in neurological (brain), muscoskeletal, cardiovascular, and oncological cancer) imaging. Unlike CT, MRI uses no ionizing radiation. Rather, it uses a powerful magnetic field to align the nuclear magnetization of (usually) hydrogen atoms in water in the body. Radio frequency fields are used to systematically alter the alignment of this magnetization. This causes the hydrogen nuclei to produce a rotating magnetic field detectable by the scanner. This signal can be manipulated by additional magnetic fields to build up enough information to construct an image of the body.
You will lay down on a platform that will slide into the interior of the giant magnet, which is like a tunnel open at both ends. The scan usually takes from 30 to 90 minutes to perform. During the scan you will be asked to stay still so the images do not blur. You will hear some knocking or thumping noises inside the machine which is normal and to be expected.
No, an MRI scan does not hurt at all.
Just follow your doctor's instructions about eating or taking your usual medications. At the scanning site, remove all metallic objects.
When the scan in completed you may return to your normal lifestyle while you wait for the results.