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Abstract #2599

Gradient Waveform Pre-Equalization Using the Magnetic Field Gradient Waveform Monitor Method

Frederic G. Goora1, 2, Hui Han2, Bruce G. Colpitts1, Bruce J. Balcom2

1Department of Electrical and Computer Engineering, University of New Brunswick, Fredericton, New Brunswick, Canada; 2MRI Research Centre, Department of Physics, University of New Brunswick, Fredericton, New Brunswick, Canada

The accuracy of applied magnetic field gradients in magnetic resonance imaging directly impacts the corresponding image quality and measurements of molecular motion. These distortions result from the generation of eddy currents within the magnet structure and from distortion of the magnetic field gradient coil excitation current due to gradient current amplifier limitations (such bandwidth and stability) and the reactive gradient coil load which fundamentally limit the minimum excitation current rise and fall times which further distort the applied magnetic field gradient.

Keywords

accuracy added adjustments amplifier amplifiers amplitudes applications applied approximately approximation axis bandwidth basic challenges characterize clinical coil coils combination common commonly communications compensates completed concept conducted constant constants consuming converges coordinates correct corrected corresponds custom defined described desired despite determine determined developed differ directly discussed distort distortion distortions eddy efforts emphasis employed encountered entire environment equalization equalized excitation exercise exponential fall field fixed former frames functions fundamental fundamentally generation gradient gradients guided half ideal identify impacts improvements infidelity instruments iteration iterations knowledge latter lead limit limitations limits linear load located longitudinal magnet measure measured minutes molecular monitor motion observation optimal optimized oxford performance permanent phys pieces pole post probe procedure process processing pulse quality reactive reasons reconstruction reduced repeated required respectively response rise sample setting several shield solenoid sophisticated sources space stability stage still strategy structure synchronized system systems tedious tends tens transverse turn typically utilizes validated waveform waveforms