McJury M, Stewart R W, Crawford D, Toma E
Department of Electrical and Electronic Engineering, University of Strathclyde, Glasgow, UK.
Magn Reson Imaging. 1997;15(3):319-22. doi: 10.1016/s0730-725x(96)00337-2.
MRI scanning generates high levels of acoustic noise that cannot only pose a safety hazard, but also impair communication between staff and patient. In this article we present active noise control (ANC) techniques that introduce antiphase noise to destructively interfere with the MRI noise and with the aim of producing a zone of quiet around the patient's ears. Using noise recorded from a 1.0 Tesla midfield MR scanner the acoustic noise generated by three standard MR imaging sequences was replayed to a real time two channel ANC system. The results obtained show a useful attenuation of low-frequency periodic acoustic noise components. Therefore, in combination with standard passive ear protection, this suggests that MR generated acoustic noise can be effectively attenuated at both low and high frequencies leading to improved patient comfort.
磁共振成像（MRI）扫描会产生高强度的噪音，这不仅会构成安全隐患，还会影响工作人员与患者之间的沟通。在本文中，我们介绍了主动噪声控制（ANC）技术，该技术引入反相噪声以对MRI噪声进行相消干涉，目的是在患者耳部周围产生一个安静区域。利用从一台1.0特斯拉中场磁共振扫描仪记录的噪声，将三个标准磁共振成像序列产生的声学噪声重放至一个实时双通道主动噪声控制系统。所获得的结果表明，低频周期性声学噪声成分得到了有效衰减。因此，结合标准的被动耳部防护措施，这表明磁共振产生的声学噪声在低频和高频都能得到有效衰减，从而提高患者的舒适度。
