Premium
Direct B 0 field monitoring and real‐time B 0 field updating in the human breast at 7 tesla
Author(s) -
Boer Vincent O.,
vd Bank Bart L.,
van Vliet Gerard,
Luijten Peter R.,
Klomp Dennis W. J.
Publication year - 2012
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.23272
Subject(s) - shim (computing) , magnetic field , field (mathematics) , nuclear magnetic resonance , sensitivity (control systems) , magnetostatics , reproducibility , spectroscopy , physics , optics , materials science , chemistry , electronic engineering , mathematics , medicine , chromatography , quantum mechanics , pure mathematics , erectile dysfunction , engineering
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.