Application of self-refocusing band selective RF pulses for spectroscopic localization

A new self-refocusing slice selection 90 degrees pulse is presented and its incorporation in the SPACE localization sequence described. Experimental comparisons are made with the self-refocusing pulse reported by Geen (H. Geen, S. Wimperis and R. Freeman, J. Magn. Reson. 85, 620 (1990)). The main source of localization error in the SPACE sequence is traced to the hard pi/2 pulse and the development of a shaped-pulse version of the sequence is described. This required the calculation of a slice-selective pulse capable of rotating coherent transverse magnetization to the z-axis. The RF power requirements for these experiments are also discussed.