Related Experiment Video
Updated: Aug 26, 2026

Quantitative Magnetic Resonance Imaging of Skeletal Muscle Disease
Published on: December 18, 2016
Relationship between magnetic field strength and magnetic-resonance-related acoustic noise levels
Adriaan Moelker1, Piotr A Wielopolski, Peter M T Pattynama
1Department of Radiology, Erasmus Medical Center Rotterdam, 50 Dr Molewaterplein, 3000 DR Rotterdam, The Netherlands. moelker@erasmusmc.nl
Abstract:
The need for better signal-to-noise ratios and resolution has pushed magnetic resonance imaging (MRI) towards high-field MR-scanners for which only little data on MR-related acoustic noise production have been published. The purpose of this study was to validate the theoretical relationship of sound pressure level (SPL) and static magnetic field strength. This is relevant for allowing adequate comparisons of acoustic data of MR systems at various magnetic field strengths. Acoustic data were acquired during various pulse sequences at field strengths of 0.5, 1.0, 1.5 and 2.0 Tesla using the same MRI unit by means of a Helicon rampable magnet. Continuous-equivalent, i.e. time-averaged, linear SPLs and 1/3-octave band frequencies were recorded. Ramping from 0.5 to 1.0 Tesla and from 1.0 to 2.0 Tesla resulted in an SPL increase of 5.7 and 5.2 dB(L), respectively, when averaged over the various pulse sequences. Most of the acoustic energy was in the 1-kHz frequency band, irrespective of magnetic field strength. The relation between field strength and SPL was slightly non-linear, i.e. a slightly less increase at higher field strengths, presumably caused by the elastic properties of the gradient coil encasings.
Related Concept Videos
Atomic Nuclei: Magnetic Resonance
Atomic Nuclei: Nuclear Relaxation Processes
NMR Spectrometers: Resolution and Error Correction
Magnetic Fields
A magnetic field is defined by the force that a charged particle experiences...
Magnetic Resonance Imaging
Magnetic Susceptibility and Permeability
When diamagnetic materials are placed under an external magnetic field, the moments opposite to the field are induced. Hence, the susceptibility for diamagnets has a minimal negative value of 10-5–10-6. Since...

