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Characterization and prediction of gradient acoustic noise in MR imagers
Author(s) -
Hedeen Robert A.,
Edelstein William A
Publication year - 1997
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.1910370103
Subject(s) - noise (video) , acoustics , physics , gradient noise , scanner , pulse sequence , sensitivity (control systems) , white noise , signal (programming language) , pulse (music) , nuclear magnetic resonance , noise floor , optics , noise measurement , computer science , noise reduction , telecommunications , electronic engineering , artificial intelligence , detector , image (mathematics) , programming language , engineering
Gradient acoustic noise has been measured and characterized for an epoxy‐potted, shielded gradient assembly in a 1.5 T MRI system. Noise levels vary by 10 dB or more as a function of longitudinal position in the scanner and reflect the pattern of forces applied to the gradient assembly. The noise level increases slightly (1–3 dB) with a patient in the scanner. The spectrum of the noise is similar (but not identical) to the spectrum of the input signal. A gradient‐pulse‐to‐acoustic‐noise transfer function was obtained by using a white noise voltage input to the gradient system. The transfer function enabled us to accurately predict acoustic noise output for a pulse sequence consisting of a series of trapezoidal pulses on a single axis and for a clinical fast spin echo sequence with gradients present on all three axes.