magnetic resonance imaging

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Related to Magnetic resonance spectroscopy: Nuclear magnetic resonance spectroscopy

magnetic resonance imaging

(MRI), noninvasive diagnostic technique that uses nuclear magnetic resonancemagnetic resonance,
in physics and chemistry, phenomenon produced by simultaneously applying a steady magnetic field and electromagnetic radiation (usually radio waves) to a sample of atoms and then adjusting the frequency of the radiation and the strength of the magnetic field
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 to produce cross-sectional images of organs and other internal body structures. The patient lies inside a large, hollow cylinder containing a strong electromagnet, which causes the nuclei of certain atoms in the body (especially those of hydrogen) to align magnetically. The patient is then subjected to radio waves, which cause the aligned nuclei to "flip"; when the radio waves are withdrawn the nuclei return to their original positions, emitting radio waves that are then detected by a receiver and translated into a two-dimensional picture by computer. Unhampered by bone and capable of producing images in a variety of planes, MRI is used in the diagnosis of brain tumors and disorders, spinal disorders, multiple sclerosis, and cardiovascular disease. The procedure is considered to be without risk, but the scanner may interfere with pacemakers, hearing aids, or other mechanical devices. Although the images are similar in many ways to those of CAT scansCAT scan
[computerized axial tomography], X-ray technique that allows relatively safe, painless, and rapid diagnosis in previously inaccessible areas of the body; also called CT scan.
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, they are obtained without X rays or other radiation, and generally provide more contrast between normal and abnormal tissue.

magnetic resonance imaging

[mag′ned·ik ′rez·ən·əns ′im·ij·iŋ]
(engineering)
A technique in which an object placed in a spatially varying magnetic field is subjected to a pulse of radio-frequency radiation, and the resulting nuclear magnetic resonance spectra are combined to give cross-sectional images. Abbreviated MRI.
References in periodicals archive ?
Application of pattern recognition methods to the analysis and classification of toxicological data derived from proton nuclear magnetic resonance spectroscopy of urine.
On magnetic resonance spectroscopy, increased levels of glutamine, glutamate, and choline were seen in white matter and to a lesser extent in the basal ganglia of patients with abnormal neuropsychological test findings.
The scientists extracted material at each step of the transformation and used nuclear magnetic resonance spectroscopy to determine the ratio of carbon to fluorine atoms.
Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy, is a research technique that exploits the magnetic properties of certain atomic nuclei to determine the physical and chemical properties of atoms, or the molecules in which they are contained.
Among their topics are miscible blends based on biodegradable polymers, characterizing polymer blends and block copolymers by neutron scattering: miscibility and nanoscale morphology, the dynamic mechanical thermal analysis of polymer blends, the electron microscopic analysis of multi-component polymers and blends, characterizing polymer blends with solid-state nuclear magnetic resonance spectroscopy, and positron annihilation spectroscopy.
To noninvasively study metabolism in the brains of the children, the researchers used proton (hydrogen) magnetic resonance spectroscopy (HMRS), a common adjunct to structural MRI studies.
Over the course of the two volumes, 17 chapters discuss the thermochemistry of peroxides, nuclear magnetic resonance spectroscopy, synthesis of cyclic peroxides, uses of peroxides in synthesis, and peroxides in biological systems.
Magnetic resonance spectroscopy combined with special computer software analyzes thousands of chemicals in cells obtained by fine needle biopsy and matches the results with pathology information stored in the computer database.
In their study, 35 coronary artery bypass graft patients underwent neurologic examination, neuropsychologic examination, diffusion-weighted MRI, and magnetic resonance spectroscopy before and after the cardiac procedure (Arch.
Pettegrew, a neuroscientist at the University of Pittsburgh, uses nuclear magnetic resonance spectroscopy to examine debris from cell-membrane breakdown in the brains of living Alzheimer's patients.
NYSE:A) and the Agilent Technologies Foundation today announced that professor Gerhard Wagner at Harvard Medical School has received an Agilent Thought Leader Award in support of his work using high-magnetic-field nuclear magnetic resonance spectroscopy to analyze large proteins.
The researchers found similar patterns using two independent assays - nuclear magnetic resonance spectroscopy on blood serum and cavity ring-down spectroscopy on exhaled breath.

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