Trajectory calculation for spiral imaging based on concurrent reading of the gradient amplifiers’ internal current sensors

Spiral sequences sample data during gradient variation and are therefore susceptible to dynamic field deviations caused by eddy currents, timing inaccuracies, or gradient amplifier non-linearities. Linear effects can be corrected using a gradient impulse response function for trajectory calculation. Non-linear effects require a measurement-based approach, e.g. measurement of the gradient fields during imaging using a field camera or an induction-based field measurement. To avoid the need for additional hardware, we propose a hybrid method that combines current measurements using the amplifier-internal current sensors with correction based on the current-to-gradient impulse response function. The approach improves trajectory accuracy in spiral imaging.