Numerical Calculations of Switched Magnetic Field Gradients During Magnetic Resonance Imaging

Abstract

During magnetic resonance imaging (MRI) pulse-sequences the human body is exposed to switched magnetic gradient fields. These gradients become stronger and are switched faster for fast imaging. Effects resulting from these fields with trapezoidal waveforms are on the one hand sensory perception of induced currents and on the other hand muscular and cardiac stimulation. All three components of the current density induced by gradient pulse sequence were analysed in a high-resolution model of the human torso. The evaluation of the calculated data was performed thoroughly in the region of the heart muscle of the torso model to find out how different waveforms of the switched gradient field influence strength and direction of induced currents.

Using magnetic field gradients to control the directional solidification of alloys and the growth of single crystals

“…This has immediate consequences while attempting the control of melt flow during the growth of the crystal. Given the recent rapid developments in the field of super conducting magnets and magnetic resonance imaging (MRI), the commercial production of these magnetic gradients is very feasible [18][19][20][21][22]. Further, there are many commercially available gradient field production coils that could be incorporated into existent crystal growth furnaces.…”