Longman Dictionary of Contemporary English
The Collaborative International Dictionary
magnetic resonance imaging \mag*net"ic res"on*ance im"ag*ing\ n. (Medicine) a medical diagnostic procedure utilizing the phenomenon of nuclear magnetic resonance to generate images of internal parts of the body. It depends on the differential absorption of electromagnetic radiation by different types of living tissue in a magnetic field. It is complementary to X-ray imaging in that the softer tissue show more prominently in magnetic resonance images, rather than bone, as with X-rays. It is a non-invasive procedure, allowing such images to be obtained without penetration of the tissue by objects. It is abbreviated MRI. As with computerized tomography, the results are usually presented as images of sequential planar sections of that part of the body of concern to the physician.
Wiktionary
n. (context medicine English) A technique that uses nuclear magnetic resonance to form cross sectional images of the human body for diagnostic purposes.
WordNet
n. the use of nuclear magnetic resonance of protons to produce proton density images [syn: MRI]
Wikipedia
Magnetic resonance imaging (MRI), nuclear magnetic resonance imaging (NMRI), or magnetic resonance tomography (MRT) is a medical imaging technique used in radiology to image the anatomy and the physiological processes of the body in both health and disease. MRI scanners use strong magnetic fields, radio waves, and field gradients to form images of the body.
MRI is based upon the science of Nuclear Magnetic Resonance (NMR). Certain atomic nuclei can absorb and emit radio frequency energy when placed in an external magnetic field. In clinical and research MRI, hydrogen atoms are most-often used to generate a detectable radio-frequency signal that is received by antennas in close proximity to the anatomy being examined. Hydrogen atoms exist naturally in people and other biological organisms in abundance, particularly in water and fat. For this reason, most MRI scans essentially map the location of water and fat in the body. Pulses of radio waves excite the nuclear spin energy transition, and magnetic field gradients localize the signal in space. By varying the parameters of the pulse sequence, different contrasts can be generated between tissues based on the relaxation properties of the hydrogen atoms therein. Since its early development in the 1970s and 1980s, MRI has proven to be a highly versatile imaging technique. While MRI is most prominently used in diagnostic medicine and biomedical research, it can also be used to form images of non-living objects. MRI scans are capable of producing a variety of chemical and physical data, in addition to detailed spatial images.
MRI is widely used in hospitals and clinics for medical diagnosis, staging of disease and follow-up without exposing the body to ionizing radiation.
Magnetic Resonance Imaging is a peer-reviewed scientific journal published by Elsevier, encompassing biology, physics, and clinical science as they relate to the development and use of magnetic resonance imaging technology. Magnetic Resonance Imaging was established in 1982 and the current editor-in-chief is John C. Gore. The journal produces 10 issues per year.
Usage examples of "magnetic resonance imaging".
The doctors knew this but wanted to see what the physicists could tell them from the nuclear magnetic resonance imaging.
He started a second company, Advanced Magnetics, which owned several patents essential for the new Magnetic Resonance Imaging machines that were starting to revolutionize medicine.
Squire presented a magnetic resonance imaging (MRI) brain scan showing details of the hippocampus.
Functional Magnetic Resonance Imaging, a primitive system dependent upon alternations in magnetic susceptibility and designed to measure, in the brain at least and very crudely, areas of neural activation.
Twice we miniaturized chimpanzees and twice we brought them back and could detect no changes in them -- either as a result of minute studies of their behavior or by magnetic resonance imaging of the brain.
I was examined, x-rayed, scanned, subjected to positron emission tomography and magnetic resonance imaging, covered by four hundred electrodes, strapped to a special chair, and asked to look through a slit at pictures of apples, dogs, forks, combs, old people, tables, mice, mushrooms, cigars, glasses, nude women, and babies, after which they told me what I already knew: that when they showed me a billiard ball so that only my left hemisphere could see it and at the same time put my right hand into a bag with many objects, I wasn't able to choose the ball, and vice versa.
Recently neurologists at Germany's Heinrich Heine University used magnetic resonance imaging to discover that musicians with perfect pitch apparently process sounds in the planum temporale of the left cortex Since it's been shown that music is ordinarily processed in the right cortex, perfect pitch may be closely related to the language ability that occurs more in the left cortex.
With that power, and continuing improvements in brain scanning techniques such as magnetic resonance imaging, Kurzweil says a machine with the full mental capacities of human beings -- the first full AI --will appear by 9.