Direct B 0 field monitoring and real‐time B 0 field updating in the human breast at 7 tesla
Abstract Large dynamic fluctuations of the static magnetic field ( B 0 ) are observed in the human body during MR scanning, compromising image quality and detection sensitivity in several MR imaging and spectroscopy sequences. Partially, these dynamic B 0 fluctuations are due to physiological motion...
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Published in | Magnetic resonance in medicine Vol. 67; no. 2; pp. 586 - 591 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
01.02.2012
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Online Access | Get full text |
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Summary: | Abstract
Large dynamic fluctuations of the static magnetic field (
B
0
) are observed in the human body during MR scanning, compromising image quality and detection sensitivity in several MR imaging and spectroscopy sequences. Partially, these dynamic
B
0
fluctuations are due to physiological motion such as breathing, but other sources of temporal
B
0
field fluctuations are also present in the MR system (e.g., eddy currents). Especially at ultrahigh field (≥7 T), the increased susceptibility effects lead to large
B
0
field variations over time. Direct measurement and correction of these temporal field variations of up to 70 Hz will lead to a significant reduction of artifacts and improved measurement stability/reproducibility. For direct measurement of the temporally changing
B
0
field, a simple field probe was developed, that was placed in proximity to the tissue of interest. In this work, it is shown how such a field probe system can be used to monitor temporal
B
0
field variations in the human body during MRI and magnetic resonance spectroscopy. Furthermore, it is shown how the acquired temporal
B
0
field information can drive a dynamic shim module to directly correct the
B
0
magnetic field in real time. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc. |
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ISSN: | 0740-3194 1522-2594 |
DOI: | 10.1002/mrm.23272 |