Spectrally selective imaging with wideband balanced steady‐state free precession MRI

Purpose Unwanted, bright fat signals in balanced steady‐state free precession sequences are commonly suppressed using spectral shaping. Here, a new spectral‐shaping method is proposed to significantly improve the uniformity of stopband suppression without compromising the level of passband signals. Methods The proposed method combines binomial‐pattern excitation pulses with a wideband balanced steady‐state free precession sequence kernel. It thereby increases the frequency separation between the centers of pass and stopbands by π radians, enabling improved water‐fat contrast. Simulations were performed to find the optimal flip angles and subpulse spacing for the binomial pulses that maximize contrast and signal efficiency. Results Comparisons with a conventional binomial balanced steady‐state free precession sequence were performed in simulations as well as phantom and in vivo experiments at 1.5 T and 3 T. Enhanced fat suppression is demonstrated in vivo with an average improvement of 58% in blood‐fat and 68% in muscle‐fat contrast ( P  < 0.001, Wilcoxon signed‐rank test). Conclusion The proposed binomial wideband balanced steady‐state free precession method is a promising candidate for spectrally selective imaging with enhanced reliability against field inhomogeneities. Magn Reson Med 75:1132–1141, 2016. © 2015 Wiley Periodicals, Inc.