Acoustic Analysis of MRI Noise and Induced Hearing Loss

Yun, Jun Ho; Chon, Kyong Myong; Koo, Soo Kweon; Song, Chang Yoon; Kim, Hyun Kyu; Lee, Sang Hwa

Abstract

BACKGROUND AND OBJECTIVES
Magnetic resonance (MR) imaging has resulted in a tremendous advance in the technology of medical diagnosis. However, even with all positive advances, there are usually some negative aspects, especially noise. It is well known that loud sounds can induce a hearing loss. This study was performed to determine the acoustic characteristics of MRI noise and whether or not the sound exposure resulting from routine MRI examinations is capable of altering the auditory thresholds of patients. MATERIALS AND METHOD: Digital Impulse Sound Level Meter was placed at patient's head level and at a 2m distance. Frequency of MRI noise was recorded by Digital audio tape and analyzed by Computerized Sound Lab (CSL). A total of 53 adults (106 ears) who were scheduled for MR imaging studies were included in the study. Pure-tone air-conductive auditory threshold was determined bilaterally in each patient before and after MRI. RESULTS: The noise levels at head level ranged from 80.8 dB to 86.0 dB, and at a 2 m distance, from 71.9 dB to 75.9 dB. The frequency ranged from 60 Hz to 2500 Hz. Nine of the 106 ears had a hearing loss of at least 10 dB at one frequency. CONCLUSION: The noise generated by the MRI is sufficiently intense to cause some temporary threshold shifts (TTS). TTS may transform to permanent threshold shifts. Therefore, it is important to devise a method to minimize the risk of these shifts, for example, by using earplug.