High-resolution Fourier-encoded sub-millisecond echo time musculoskeletal imaging at 3 Tesla and 7 Tesla

Abstract

Purpose The feasibility of imaging musculoskeletal fibrous tissue components, such as menisci, ligaments, and tendons, with a conventional spoiled gradient echo technique is explored in vivo at 3 T and 7 T. Methods To this end, the echo time (TE1) of a conventional Fourier-encoded multicontrast three-dimensional SGPR sequence is minimized by using nonselective excitation pulses, highly asymmetric readouts, and a variable TE1 along the phase and slice encoding direction. In addition, a fully sampled second echo image (with TE2 >> TE1) can be used to highlight components with short transverse relaxation times in a difference image with positive contrast. Results Fourier-encoded spoiled gradient echo sequences are able to provide sub-millisecond TE1 of about 800 μs for typical in-plane resolutions of about 0.5 x 0.5 mm2. As a result, high-resolution positive contrast images of fibrous tissues can be generated within clinically feasible scan-time of about 2-7 minutes. Conclusion After optimization, Fourier-encoded spoiled gradient echo provides a highly robust and flexible imaging technique for high-resolution positive contrast imaging of fibrous tissue that can readily be used in the clinical routine. Magn Reson Med 70:1434-1439, 2013. © 2012 Wiley Periodicals, Inc. Copyright © 2012 Wiley Periodicals, Inc.