Gregory R. Lee1, Jean A. Tkach1,2,
Mark A. Griswold1,3
1Radiology, Case Western
Reserve University, Cleveland, OH, United States; 2Radiology,
Imaging Research Center, Cincinnati Children's Hospital Research Foundation,
Cincinnati, OH, United States; 3Biomedical Engineering, Case
Western Reserve University, Cleveland, OH, United States
At 3T and above, spectral-spatial (SPSP) subpulse durations of less than 1 ms are needed in order to selectively excite either water or fat spins. With such short subpulses, RF power limits prohibit the excitation of sharp spatial slabs when using traditional SPSP pulse designs. In the present work, a new algorithm for alternating between minimum-time VERSE gradient waveform reshaping and RF pulse redesign is presented. The algorithm can produce much sharper spatial slabs while preserving the spectral profile. In addition, there is flexibility in the specification of the SPSP excitation pattern and tip-down time within the pulse.