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.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1002/mrm.1910370103 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
A method of enhanced shear wave elastography based on Chirp coded excitation.
Ultrasonics
January 2025
Medical Ultrasound Department for the Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, Jiangsu 215163, China. Electronic address:
Shear Wave Elastography (SWE) is an imaging technique that detects shear waves generated by tissue excited by Acoustic Radiation Force (ARF), and characterizes the mechanical properties of soft tissue by analyzing the propagation velocity of shear wave. ARF induces a change in energy density through the nonlinear propagation of ultrasound waves, which drives the tissue to generate shear waves. However, the amplitude of shear waves generated by ARF is weak, and the shear waves are strongly attenuated in vivo.
View Article and Find Full Text PDFComparing approaches for predicting behavioural speech-in-noise performance using cortical responses to unattended stimuli.
Hear Res
January 2025
Institute of Sound and Vibration Research, University of Southampton, Southampton, United Kingdom.
The cortical tracking of the acoustic envelope is a phenomenon where the brain's electrical activity, as recorded by electroencephalography (EEG) signals, fluctuates in accordance with changes in stimulus intensity (the acoustic envelope of the stimulus). Understanding speech in a noisy background is a key challenge for people with hearing impairments. Speech stimuli are therefore more ecologically valid than clicks, tone pips, or speech tokens (e.
View Article and Find Full Text PDFExploring freshwater soundscapes of tropical marshland habitats in Southeast Asia: insights into auditory sensory adaptation of wild Siamese fighting fish .
PeerJ
January 2025
Institute of Science and Environment, University of Saint Joseph, Macao, Macao S.A.R., China.
While soundscapes shape the structure and function of auditory systems over evolutionary timescales, there is limited information regarding the adaptation of wild fish populations to their natural acoustic environments. This is particularly relevant for freshwater ecosystems, which are extremely diverse and face escalating pressures from human activities and associated noise pollution. The Siamese fighting fish is one of the most important cultured species in the global ornamental fish market and is increasingly recognized as a model organism for genetics and behavioural studies.
View Article and Find Full Text PDFErratum: Short-term noise annoyance towards drones and other transportation noise sources: A laboratory study [J. Acoust. Soc. Am. 156(4), 2578-2595 (2024)].
J Acoust Soc Am
January 2025
Laboratory for Acoustics/Noise Control, Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland.
A platform noise dataset of various types of subway stations during all operating hours.
Sci Data
January 2025
ZheJiang Communications Investment Group Co., Ltd., ITS Branch, Hangzhou, 310000, China.
The subjective perceptions of passengers are intricately linked to the noise levels in subway stations of urban rail transit systems. In this study, comprehensive measurement was conducted on the noise environment on the platforms during operational hours at four distinct types of subway stations within an urban metro network. To ensure precise data collection, four different noise and sound pressure measurement points were strategically positioned in the middle and at both ends of each station platform.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!