Quiet transverse gradient coils: Lorentz force balanced designs using geometrical similitude

The principle of active acoustic screening, recently introduced by Mansfield et al. (1) to reduce acoustic noise in gradient coils for MRI, is applied to the design of transverse distributed gradient coils of the fingerprint design. The results indicate that for complete Lorentz force balancing and for exact satisfaction of Kirchoff's law, it is necessary to have a coil system wound on four cylinders if full active magnetic screening of the assembly is required.