A Method for Characterizing the Magnetic Field Response of a Gradient System

Signe Johanna Vannesj¹, Maximilian Hberlin¹, Lars Kasper¹, Christoph Barmet¹, Klaas Paul Pruessmann¹

MRI relies on dynamic linear gradients for signal encoding, but the realization of given gradient time-courses is usually imperfect due to physical limitations. To characterize the magnetic field response to gradient-channel inputs the system is here treated as a linear time-invariant system that can be fully described by its impulse response functions. The field response was measured up to 3rd order in space with a dynamic field camera, consisting of 16 NMR probes. The measured impulse response functions allowed for accurate prediction of actual k-space trajectories and also showed predictable higher-order effects.