| Induced magnetic field gradients and forces in the human head in MRI. | |
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MedLine Citation:
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PMID: 17969175 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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PURPOSE: To map the induced magnetic field gradients and estimate the magnetic force in the human head during magnetic resonance imaging at 4 Tesla (T). MATERIALS AND METHODS: The magnetic field distribution in the human head was measured using two gradient-echo experiments with different echo times. The phase of the complex image ratio removed the wrapping artifact, characteristic of phase images, and was used to map the magnetic field distribution and calculate the accurate maps of the magnetic field gradients in the human head. RESULTS: The time-independent gradient fields induced by air/tissue interfaces in the head can be 50 times larger than those resulting from the magnetic field inhomogeneity of the MRI magnet. However, the associated magnetic force in the brain is by far smaller than the gravitational force. CONCLUSION: The induced gradient fields increase the magnetic force on tissues. However, even for tissue components with large magnetic susceptibility such as iron-containing proteins, this force is negligible compared with the gravitational force. Therefore, this study suggests that static and uniform magnetic fields do not have a significant risk for the tissues in the head. |
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Authors:
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Dardo G Tomasi; Ruiliang Wang |
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Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, Non-P.H.S. |
Journal Detail:
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Title: Journal of magnetic resonance imaging : JMRI Volume: 26 ISSN: 1053-1807 ISO Abbreviation: J Magn Reson Imaging Publication Date: 2007 Nov |
Date Detail:
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Created Date: 2007-11-05 Completed Date: 2008-01-22 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9105850 Medline TA: J Magn Reson Imaging Country: United States |
Other Details:
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Languages: eng Pagination: 1340-5 Citation Subset: IM |
Affiliation:
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Medical Department, Brookhaven National Laboratory, Upton, New York 11973, USA. tomasi@bnl.gov |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Brain
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physiopathology*,
radiation effects* Computer Simulation Electromagnetic Fields Energy Transfer Head / physiology*, radiation effects* Humans Magnetic Resonance Imaging* Models, Biological Models, Neurological* Radiation Dosage Radiometry / methods* Stress, Mechanical |
| Grant Support | |
ID/Acronym/Agency:
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5-M01-RR-10710/RR/NCRR NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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