Abstract #4780

Acoustic Noise Reduction Through Pulse Sequence Design: Timings, Eddy-Currents, FMRI

Xingxian Shou¹, Xin Chen¹, Jamal J. Derakhshan², Jeffrey L. Duerk^2,3, Robert W. Brown¹

¹Department of Physics, Case Western Reserve University, Cleveland, OH, USA; ²Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA; ³Department of Radiology, University Hospitals, Cleveland, OH, USA

We have carried out further investigations of the mechanism of suppression of dominant frequencies in the acoustic noise spectra through impulsive - anti-impulsive Lorentz force cancellations. Pulse sequence timing recipes are given for killing multiple frequencies. The distinction between the Fourier transform envelope and its zeros for frequency suppression is emphasized. We establish that frequency clusters due to vibrations generated by eddy-currents are suppressed in exactly the same way as those due to gradient vibrations. Finally, it is pointed out that dominant noise peaks, which have a major influence on auditory fMRI studies, may be suppressed with this mechanism.