Efficient implementation of hardware-optimized gradient sequences for real-time imaging.

This work improves the performance of interactive real-time imaging with balanced steady-state free precession. The method employs hardware-optimized gradient pulses, together with a novel phase-encoding strategy that simplifies the design and implementation of the optimized gradient waveforms. In particular, the waveforms for intermediate phase-encode steps are obtained by simple linear combination, rather than separate optimized waveform calculations. Gradient waveforms are redesigned in real time as the scan plane is manipulated, and the resulting sequence operates at the specified limits of the MRI gradient subsystem for each new scan-plane orientation. The implementation provides 14-25% improvement in the sequence pulse repetition time over the vendor-supplied interactive real-time imaging sequence for similar scan parameters on our MRI scanner.