Titre :

Acoustic noise levels and field distribution in 7 T MRI scanners

Auteur(s) :

Shtrepi, Louena [Auteur]
Politecnico di Torino = Polytechnic of Turin [Polito]
Poggetto, Vinicius [Auteur]
Università degli Studi di Trento = University of Trento [UNITN]
Durochat, Clement [Auteur]
Dubois, Marc [Auteur]
Bendahan, David [Auteur]
Centre de résonance magnétique biologique et médicale [CRMBM]
Nistri, Fabio [Auteur]
Politecnico di Torino = Polytechnic of Turin [Polito]
Miniaci, Marco [Auteur]
Acoustique - IEMN [ACOUSTIQUE - IEMN]
Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 [IEMN]
Pugno, Nicola Maria [Auteur]
Università degli Studi di Trento = University of Trento [UNITN]
Bosia, Federico [Auteur]
Department of Applied Science and Technology [Politecnico di Torino] [DISAT]
Politecnico di Torino = Polytechnic of Turin [Polito]

Titre de la revue :

Frontiers in Physics

Éditeur :

Frontiers

Date de publication :

2023-11-14

ISSN :

2296-424X

Mot(s)-clé(s) en anglais :

magnetic resonance imaging
acoustics
noise measurement
modal analysis
finite element simulation

Discipline(s) HAL :

Sciences de l'ingénieur [physics]
Physique [physics]

Résumé en anglais : [en]

Acoustic noise production during Magnetic Resonance Imaging is an important source of patient discomfort and leads to verbal communication problems, difficulties in sedation, and hearing impairment. To address these issues, ...
Lire la suite >Acoustic noise production during Magnetic Resonance Imaging is an important source of patient discomfort and leads to verbal communication problems, difficulties in sedation, and hearing impairment. To address these issues, in this paper we present a systematic characterization of the acoustic field distribution in a MRI cavity in a last generation 7 T scanner, in different spatial locations, with and without a phantom head. Analysis and comparison of various MRI sequences like Echo-planar imaging”, “Gradient echo”, “Spin echo” are carried out. Sound pressure levels are measured using standard statistical descriptors ( L e q , L m e a n , L 90 , and L m o d e ) using two prepolarized free-field microphones measuring pressure levels generated inside scanner cavities in a 50 Hz to 10 kHz range. Acoustic eigenmodes of the cavity are derived numerically in finite element simulations and compared to measurements. Equivalent sound pressure levels exceed 85 dB in the range between 500 and 3,000 Hz, and peak levels are consistently above 100 dB, i.e., the noise levels of 7 T scanners are higher than 3T and 1.5 T counterparts. The presence of the phantom head in the MRI scanner leads to increased noise levels (by 5–10 dB) in its vicinity, as a result of reflections occurring between the head and the bore reflective walls. Numerical finite element simulations allow to extrapolate the noise distribution in the entire cavity and to interpret experimental results and indicate that the frequencies at which the highest noise levels occur correspond to azimuthal or radial resonant modes of the MRI cavity, i.e., with a radially and azimuthally varying pressure field. These results can be useful for the design of future acoustic noise mitigation solutions.Lire moins >

Langue :

Anglais

Comité de lecture :

Oui

Audience :

Internationale

Vulgarisation :

Non

Projet ANR :

INITIATIVE D'EXCELLENCE AIX MARSEILLE UNIVERSITE

Collections :

• Institut d'Électronique, de Microélectronique et de Nanotechnologie (IEMN) - UMR 8520

Source :

Harvested from HAL