Design Considerations for Ultra High Field MRI Magnet Systems
Magnetic field strength has always been an important parameter to consider for Magnetic Resonance Imaging (MRI). It is generally agreed that the Signal to Noise Ratio (SNR) is approximately proportional to magnetic field strength [1,2], although other more subtle effects, such as chemical shift dispersion and susceptibility, also scale with field strength and can cause problems for good anatomical imaging. However, it is no surprise to learn that the engineering challenges presented by the commercial construction of higher field MRI systems are formidable. This chapter is an opportunity to introduce these to a wider audience.
KeywordsAcoustic Noise Magnetic Resonance Image System General Electric Medical System Gradient Coil Stray Field
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- 1.Hoult DI, Richards RE. 1976. The signal-to-noise ratio of the nuclear magnetic resonance experiment. J Magn Reson 24:71–83.Google Scholar
- 9.Wilson MN. 1998. Superconducting magnets. Oxford: Oxford UP.Google Scholar
- 11.Roopchansingh V, Jesmanowicz A, Hyde JS. 2004. Magnetic field homogeneity improvement in the lower frontal lobe by combined resistive and passive shims with a user-defined mask. Proc Int Soc Magn Reson Med 1650.Google Scholar
- 12.Wong EC, Mazaheri Y. 2004. Shimming of the inferior frontal cortex using an external local shim coil. Proc Int Soc Magn Reson Med 520.Google Scholar
- 17.Hidalgo-Tobon SS, Bencsik M, Bowtell RW. 2004. Reduction of peripheral nerve stimulation via the use of combined gradient and uniform field coils. Proc Int Soc Magn Reson Med 11:659.Google Scholar
- 18.Asner FM. 1999. High-field superconducting magnets. Oxford: Oxford UP.Google Scholar
- 19.Restrictions on exposure to static and time-varying electromagnetic fields. 1995. National Radiological Protection Board, Chilton, Didcot, Oxon.Google Scholar