Spherical harmonic inductive detection coils for dynamic pre-emphasis.
The issue of eddy currents induced by the rapid switching of magnetic field gradients is a long-standing problem. A new method for dealing with this problem is presented whereby spatial harmonic components of the magnetic field are continuously sensed, through their temporal rates of change, and corrected. In this way, the effects of the eddy currents on the magnetic field can be detected and correction currents applied to the appropriate gradient or shim coils in a time much less than the rise time of the gradients. This new methodology has the potential to dynamically shape eddy current corrections for multiple spatial harmonic components of the field.
Edler
Karl
K
Institute for Biodiagnostics, National Research Council Canada, 435 Ellice Avenue Winnipeg, MB, Canada R3B 1Y6. karl.edler@nrc-cnrc.gc.ca
Hoult
David
D
D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007089:Image Enhancement / Q000295:instrumentation*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D008280:Magnetics / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014159:Transducers