Reducing the Effects of Mri Acoustic Noise Using Micro-perforated Panels

........................................................................................................................................... ii Acknowledgements ......................................................................................................................... iii Chapter 1 Introduction ................................................................................................................... 1 1.1 Purpose of Research ............................................................................................................... 1 1.2 Organization of Thesis ........................................................................................................... 2 1.3 Introduction ............................................................................................................................ 2 1.4 Overview of Magnetic Resonance Imaging (MRI) ................................................................ 3 1.4.1 Functional MRI (fMRI) .................................................................................................. 5 1.5 Noise Produced by MRI......................................................................................................... 6 1.6 Noise Reduction Methods Summary ..................................................................................... 8 1.6.1 Imaging Methods ............................................................................................................ 8 1.6.2 Active Noise Cancellation (ANC) ................................................................................ 10 1.6.3 Gradient Coil and Supports ........................................................................................... 11 1.6.4 Passive Attenuation ....................................................................................................... 12 1.7 Micro-Perforated Acoustic Absorber Panels ....................................................................... 13 1.7.1 Theory and Design ........................................................................................................ 13 1.7.2 Previous Work .............................................................................................................. 15 1.8 Summary .............................................................................................................................. 16 1.9 References ............................................................................................................................ 18 Chapter 2 Acoustic Measurements .............................................................................................. 23 2.1 Abstract ................................................................................................................................ 23 2.2 Introduction .......................................................................................................................... 23 2.3 Materials and Methods ......................................................................................................... 26 2.3.1 Acoustic Data Acquisition ............................................................................................ 28 2.3.2 Data Processing ............................................................................................................. 29 2.4 Results .................................................................................................................................. 30 2.5 Discussion ............................................................................................................................ 34 2.6 Conclusion ........................................................................................................................... 36 2.7 References ............................................................................................................................ 37 Chapter 3 fMRI Study and Perceptions ....................................................................................... 41