Rapid Acquisition of the Gradient Impulse Response Function using a Cryo-coil at 9.4 T

Motivation: Phantom-based gradient impulse response function (GIRF) measurements can characterize pre-clinical MRI gradient system changes, however duration may prohibit frequent GIRF measurement. Goal(s): Development of a fast phantom-based GIRF acquisition protocol for pre-clinical 9.4 T MRI systems using a cryo-probe and optimized phantom. Approach: A spherical phantom with shortened T1 was developed with cryo-probe and GIRF compatible geometry. A modified gradient blip scheme was developed and compared against a reference GIRF acquisition strategy. Results: Using a cryo-probe, short T1 (37 ms) and a minimal blip pattern, a GIRF acquisition time of 2.36 seconds per gradient channel was achieved at 9.4 T. Impact: Pre-clinical MR imaging systems often use application-specific hardware configurations which may influence mechanical resonances and system performance. A rapid GIRF acquisition protocol will streamline frequent system characterization. Rapid GIRF acquisition may enable new strategies for probing gradient system linearity.