How Does Magnetic Resonance Imaging (MRI) Works? : Educational World

 MRIs employ powerful magnets which produce a strong magnetic field that forces proton in the body to align with that field. When a radio frequency current is then pulsed through patient, the protons are stimulated, and spins out of equilibrium, straining against the pull of magnetic field. When the radio frequency field is turned off, the MRI sensors are able to detect the energy released as the proton realign with the magnetic field. The time it takes for the proton to align with the magnetic field, as well as the amount of energy released, changes depending on the environment and he chemical natures of molecules. Physicians are able to tell the difference between various types of tissues based on these magnetic properties.

To obtain an MRIs image patient is placed in a large magnetic box-in which magnetic field is present, and must remain still during the imaging process in order to make the image clear. Contrast agent(often containing the element Gadolinium) may be given to patient intravenously before MRI to increase the speed of alignment of proton within magnetic field. the faster the proton align the clear the image will be obtained.