MRI or Magnetic Resonance Imaging is a medical imaging technique. The technique relies on the use of a magnet that will generate a magnetic field having an effect on the hydrogen ions contained in the body
's water. It requires the patient be placed in a kind of large tube and analysis of results by computer provides quality images in 2D or, after computer reconstruction, in 3D. The patient must remain immobile in this device which, once started, is noisy. MRI allows the visualization of some tissues not normally seen on X-rays
such as ligaments. It is mainly used to view the central nervous system, the muscles
, the heart, or some tumors
. It can be coupled with a blood
vessel opacification by contrast: this is called MRA.