Optimized gradient pulse for use with EPI employing active acoustic control

The concept of active acoustic control was recently introduced by Mansfield and Haywood (MAGMA 2000:10:147–151) to ameliorate the problem of acoustic noise from MRI, particularly that from high‐speed EPI. A 30 dB reduction in noise was previously achieved with the use of acoustic control operating at spot frequencies within a narrow band. In this work, a new acoustic gradient pulse is introduced that comprises an oscillating gradient of finite duration, incorporating a combination of frequencies within this band designed for use as the switched read gradient in echo‐planar imaging (EPI). Employing this pulse with active acoustic control results in a reduction of acoustic noise by 50 dB. Magn Reson Med 50:931–935, 2003. © 2003 Wiley‐Liss, Inc.