Design, Realization and Experiments with a new RF Head Probe Coil for Human Vocal Tract Imaging in an NMR device

Přibilová²,

2016

ACTA IMEKO

The paper analyses changes in spectral properties of the acoustic noise when the examined person lies in the scanning area of the open-air magnetic resonance imager (MRI) and consequently the holder of the lower gradient coils is loaded with the mechanical mass represented by the person’s weight. The acoustic noise pressure level is mapped in the MRI neighborhood, too. Obtained results of spectral analysis will be used for design of a correction filter to suppress the noise in the simultaneously recorded speech signal for 3D modelling of the human vocal tract.

Section: Subject Experiments and Resultsmentioning

confidence: 99%

Influence of the Human Body Mass in the Open-air MRI on Acoustic Noise Spectrum

Přibilová²,

2016

ACTA IMEKO

“…We are aware of the limits of this study—at present, there exist a lot of modern MRI devices enabling parallel processing of MR images, thus rapidly shortening the necessary scanning time duration and subsequently minimizing the negative noise and vibration effect on patients. As the gradient coils are the integral part of the whole MRI equipment [6], we as users cannot make any changes to them; only external RF coils can be developed and connected to the system [24]. For the same reason, any system interference (e.g., adding new materials for damping of mechanical vibrations) cannot be recommended or advised as the output of this study.…”

Section: Discussionmentioning

confidence: 99%

Analysis of the Influence of Different Settings of Scan Sequence Parameters on Vibration and Noise Generated in the Open-Air MRI Scanning Area

Přibilová

2019

Sensors

A system of gradient coils of the magnetic resonance imaging (MRI) device produces significant vibration and noise. Energetic relations of these phenomena are analyzed depending on MRI scan parameters (sequence type, repetition time (TR), echo time (TE), slice orientation, body weight). This issue should be investigated because of negative physiological and psychological effects on a person exposed to vibration and acoustic noise. We also measured the sound pressure level in the MRI scanning area and its vicinity in order to minimize these negative impacts, depending on intensity and time duration of exposition. From the recorded vibration and noise signals, the energy parameters were determined and statistically analyzed, and the obtained results were visually and numerically compared. Finally, subjective evaluation by a listening test method was used to analyze the influence of the generated MRI noise on the human psyche.

“…The first one corresponds to the "clean" speech signal of phonation without any MRI noise, only with the superimposed background noise of the temperature stabilizer [12]. The second one is composed of phonation during execution of the MR sequence SSF-3D which is usually applied for MR scanning of the human vocal tract [33].…”

Section: A Speech Signal Recording and Processingmentioning

confidence: 99%

Two Methods of Automatic Evaluation of Speech Signal Enhancement Recorded in the Open-Air MRI Environment

Přibilová²,

Measurement Science Review

2017

The paper focuses on two methods of evaluation of successfulness of speech signal enhancement recorded in the open-air magnetic resonance imager during phonation for the 3D human vocal tract modeling. The first approach enables to obtain a comparison based on statistical analysis by ANOVA and hypothesis tests. The second method is based on classification by Gaussian mixture models (GMM). The performed experiments have confirmed that the proposed ANOVA and GMM classifiers for automatic evaluation of the speech quality are functional and produce fully comparable results with the standard evaluation based on the listening test method.