WHAT IS A MRI?

MRIs use powerful magnets which produce a strong magnetic field that forces protons in the body to align with that field. When a radiofrequency current is then pulsed through the patient, the protons are stimulated, and spin out of equilibrium, straining against the pull of the magnetic field from MRI scanner machine. 

When the radiofrequency field is turned off, the MRI coils 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. 

Physicians are able to tell the difference between various types of tissues based on these magnetic properties. Multiple sequences are utilized in order to generate data needed for sequences needed as by the guidelines put out by the American College of Radiology.