Water-selective excitation of short T sub(2) species with binomial pulses

• Published in: Magnetic resonance in medicine Vol. 72; no. 3; pp. 800 - 805
• Main Authors: Deligianni, Xeni, Baer, Peter, Scheffler, Klaus, Trattnig, Siegfried, Bieri, Oliver
• Format: Journal Article
• Language: English
• Published: 01.09.2014
• ISSN: 0740-3194; 1522-2594
• DOI: 10.1002/mrm.24978

Purpose For imaging of fibrous musculoskeletal components, ultra-short echo time methods are often combined with fat suppression. Due to the increased chemical shift, spectral excitation of water might become a favorable option at ultra-high fields. Thus, this study aims to compare and explore short binomial excitation schemes for spectrally selective imaging of fibrous tissue components with short transverse relaxation time (T sub(2)). Methods Water selective 1-1-binomial excitation is compared with nonselective imaging using a sub-millisecond spoiled gradient echo technique for in vivo imaging of fibrous tissue at 3T and 7T. Results Simulations indicate a maximum signal loss from binomial excitation of approximately 30% in the limit of very short T sub(2) (0.1 ms), as compared to nonselective imaging; decreasing rapidly with increasing field strength and increasing T sub(2), e.g., to 19% at 3T and 10% at 7T for T sub(2) of 1 ms. In agreement with simulations, a binomial phase close to 90 degree yielded minimum signal loss: approximately 6% at 3T and close to 0% at 7T for menisci, and for ligaments 9% and 13%, respectively. Conclusion Overall, for imaging of short-lived T sub(2) components, short 1-1 binomial excitation schemes prove to offer marginal signal loss especially at ultra-high fields with overall improved scanning efficiency. Magn Reson Med 72:800-805, 2014. copyright 2013 Wiley Periodicals, Inc.