Acoustic noise reduction for spiral MRI by gradient derating.

Purpose: To show that the acoustic noise of spiral MRI can be reduced by derating the gradients with minimal penalty to image quality and scan time, and to illustrate an algorithm for optimal choice of derating parameters.

Theory And Methods: Acoustic noise level was measured and compared for various values of maximum gradient amplitude and slew rate for T -weighted spin-echo spiral scans while maintaining image contrast, FOV and resolution, and readout time. A full gradient trajectory and a derated gradient (undersampled) trajectory were chosen for a volunteer scan followed by parallel imaging-aided reconstruction to illustrate comparable image SNR.