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Characterization and prediction of gradient acoustic noise in MR imagers

✍ Scribed by Robert A. Hedeen; William A Edelstein

Publisher
John Wiley and Sons
Year
1997
Tongue
English
Weight
508 KB
Volume
37
Category
Article
ISSN
0740-3194

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✦ Synopsis

Abstract

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.

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