Rare Earth Magnet Basics / Glossary of Magnet Terms / MRI (Magnetic Resonance Imaging)
- MRI (Magnetic Resonance Imaging)
- MRI is the abbreviation for magnetic resonance imaging. It is a medical diagnostic device that captures cross-sectional images of the human body using nuclear magnetic resonance (NMR) of hydrogen atoms present within the body. For hydrogen atoms, the form of the electromagnetic signals generated by the nuclear magnetic resonance phenomenon differs according to the chemical and physical state of the body they are placed in. These signals are used to construct a k-space through 2-dimensional Fourier transformation and this information is presented as an image to obtain information about body tissue and lesions. Because MRIs can provide precise, detailed medical information, they have become an indispensable diagnostic technology for today's medicine. MRI devices require powerful spatial magnetic fields of 0.1T or more that are uniform to within 1/10th of geomagnetism. In order to generate such uniform magnetic fields, large magnetic circuits with super-conducting magnets and rare earth magnets are used.
The term "nuclear magnetic resonance" includes the term "nuclear", but this has no connection whatsoever to nuclear fission or nuclear radiation. Unlike X-ray medical diagnostics, it is thought that the powerful external magnetic field used in NMR diagnostics has almost no affect on the human body and MRIs are safe and useful medical diagnostics devices.
