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Determination of gradient magnetic field‐induced acoustic noise associated with the use of echo planar and three‐dimensional, fast spin echo techniques
Author(s) -
Shellock Frank G.,
Ziarati Mokhtar,
Atkinson Dennis,
Chen DarYeong
Publication year - 1998
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.1880080522
Subject(s) - microphone , noise (video) , acoustics , spin echo , physics , echo (communications protocol) , nuclear magnetic resonance , magnetic field , planar , magnetic resonance imaging , sound pressure , computer science , medicine , computer network , computer graphics (images) , quantum mechanics , artificial intelligence , image (mathematics) , radiology
The purpose of this study was to assess gradient magnetic‐field‐induced acoustic noise levels associated with the use of echo planar imaging (EPI) and three‐dimensional fast spin echo (3D‐FSE) pulse sequences. Acoustic noise measurements were obtained from two different high field‐strength MR systems (1.5 T, Siemens and General Electric Co.) under ambient noise conditions and the use of EPI and 3D‐FSE pulse sequences. Parameters were selected to produce “worst case” acoustic noise levels. Acoustic noise recordings were made at the entrance, the center, and at the exit of the magnet bores with a specially designed microphone that was unperturbed by electromagnetic fields. The highest ambient noise levels (A‐weighted scale) were 67 dB (Siemens: the same values were recorded at the center and at the exit) and 78 dB (General Electric Co.; recorded at the exit). The highest acoustic noise levels recorded during activation of the gradient magnetic fields were 114 dB (Siemens) and 115 dB (General Electric Co.) and those occurred at the centers of the MR systems with the use of the EPI technique. Gradient magnetic fields associated with the use of EPI and 3D‐FSE techniques produced acoustic noise levels that were within permissible levels recommended by federal guidelines.