What is MRI?
MRI [Magnetic Resonance Imaging] uses a powerful magnet, which produces a strong magnetic field to generate diagnostic images.
The magnetic field forces hydrogen protons in the body to align with that field. When an external radiofrequency pulse is then applied, the protons are stimulated, and spin out of equilibrium, no longer aligned with the the magnetic field.
When the radiofrequency field is turned off, the MRI sensors are able to detect the energy released as the protons realign with the magnetic field. The time it takes for the protons to realign with the magnetic field, as well as the amount of energy released, changes depending on the environment and the chemical nature of the molecules.
Radiologists are able to tell the difference between various types of normal or tissues based on these magnetic properties.