MRI Audio Equalization for Patient Audibility Under Scanner Noise

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Solution Overview

Problem

MRI and fMRI environments generate significant noise that conventional headphones and earplugs fail to adequately attenuate, causing discomfort and reducing audibility of musical stimuli, which is critical for fMRI studies.

Innovation Solution

A system that measures sound power levels in MRI environments, identifies principal frequency components, and applies audio equalization, dynamic range compression, and gain to musical signals to enhance audibility by spectrally masking noise with the music.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If headphones or earplugs are used to protect patient ears from MRI noise, then ear protection is improved, but noise attenuation is insufficient because noise transmits through tissue and bone conduction

Engineering Contradiction:

Improvenoise transmission to patient earsVSAvoidprotection effectiveness

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent uses the MRI system's own gradient coils to generate masking noise that covers the harmful gradient switching sounds. By converting the harmful noise into a beneficial masking signal, the system reduces patient discomfort without compromising protection effectiveness

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent introduces headphones as an intermediary device that delivers masking noise to the patient. This intermediary system allows controlled delivery of masking signals that can mask harmful noises while being delivered through a channel that doesn't interfere with the MRI process

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-generated harmful factors

If gradient load is reduced to lower sound pressure levels, then noise reduction is improved, but imaging quality deteriorates

Engineering Contradiction:

Improvesound pressure level from gradient coilsVSAvoidimaging quality

Core Design Contradiction:

Object-generated harmful factorsVSManufacturing precision

Solution Approach 1:

The patent converts the harmful gradient coil noise into a beneficial masking signal by processing and replaying it through headphones. This allows the gradient coils to operate at full load for high-quality imaging while the processed noise signal masks the harmful sounds for the patient

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The system performs preliminary processing of the gradient coil noise signal before it reaches the patient. By capturing, processing, and replaying the noise signal in advance, the system creates an optimized masking signal that reduces patient discomfort without affecting gradient coil performance

Inventive Principle:

Principle #10Preliminary action

3Object-generated harmful factors

If conventional noise reduction methods are applied, then maximum sound pressure level is reduced, but patient comfort and musical stimulus audibility are not sufficiently improved

Engineering Contradiction:

Improvemaximum sound pressure levelVSAvoidpatient discomfort and noise audibility

Core Design Contradiction:

Object-generated harmful factorsVSObject-affected harmful factors

Solution Approach 1:

The patent uses headphones as an intermediary to deliver processed masking noise directly to the patient's ears. This intermediary approach allows precise control of the masking signal delivery, ensuring that the processed noise effectively masks harmful sounds while maintaining patient comfort

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the parameters of the noise signal by processing it through spectral analysis and selective amplification. By modifying the frequency spectrum and temporal characteristics of the noise signal, the system creates an optimized masking signal that is more effective at reducing patient discomfort

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system effectively enhances patient audibility in MRI environments by reducing noise interference, improving comfort, and maintaining the integrity of musical signals, thereby supporting higher quality fMRI studies.

Implementation Method 1

an acoustic measuring device for measuring sound power levels generated by the MRI

Methodology Applied

Scientific EffectSound power level measurement: Sound

Implementation Method 2

preprocessing musical signals through the exploitation of spectral masking in the human auditory system to enhance audibility

Methodology Applied

Scientific EffectSpectral masking:

Data Source

PatentUS8908884B2System and method for processing signals to enhance audibility in an MRI Environment

Publication Date: 2014.12.09 UNIVERSITY OF VERMONT

AI summary

A system for processing signals to enhance patient audibility of a plurality of signals in an MRI environment is provided. The system includes an acoustic measuring device for measuring sound power levels generated by the MRI and a principal frequency component identifier for identifying principal frequencies measured by the acoustic measuring device. The system also includes an audio equalizer for controlling the amplitude and frequency of each of the plurality of signals in accordance with the principal frequencies. Further provided by the system is an attenuator for attenuating an overall sound level of the signals being processed and a dynamic range compression processor.