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Quick water‐selective excitation of fast relaxing tissues with 3D UTE sequences
Author(s) -
Springer Fabian,
Steidle Günter,
Martirosian Petros,
Grosse Ulrich,
Syha Roland,
Schabel Christoph,
Claussen Claus D.,
Schick Fritz
Publication year - 2014
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.24684
Subject(s) - yield (engineering) , excitation , contrast (vision) , pulse (music) , nuclear magnetic resonance , signal (programming language) , relaxation (psychology) , in vivo , magnetic resonance imaging , magnetization , physics , materials science , computer science , magnetic field , optics , biology , thermodynamics , medicine , microbiology and biotechnology , radiology , quantum mechanics , neuroscience , detector , programming language
Purpose The aim of this study was to implement a time effective 1‐1 double pulse water‐selective excitation (WE) into a three‐dimensional ultrashort echo time (UTE) sequence (WE‐UTE) for visualization of short‐ T 2 tissues with positive contrast and sufficient suppression of surrounding fat. Methods First, an analytical description of magnetization components in the steady state applying WE‐UTE was derived and results were compared with numerical simulations based on Bloch's equations. Parameters were optimized for best positive contrast between short‐ T 2 tissues and fat under consideration of variable relaxation properties over a broad range. Maximal signal yield and signal efficiency of on‐resonant protons were compared with UTE sequences with and without off‐resonance fat saturation (FatSat). WE‐UTE was exemplarily applied for in‐vivo musculoskeletal imaging on a 3T whole‐body MR unit. Results Steady state magnetization of WE‐UTE could be described analytically and showed excellent accordance with numerical simulations. Even for tissues with T 2 = 1 ms WE‐UTE resulted in 79% of maximal signal yield of UTE without FatSat and was more efficient regarding signal yield if compared with UTE with FatSat. Using WE‐UTE in‐vivo tendons and ligaments could be well delineated with positive contrast to surrounding fat. Conclusion WE‐UTE provides a quick method for visualizing short‐ T 2 tissues with positive contrast. Magn Reson Med 71:534–543, 2014. © 2013 Wiley Periodicals, Inc.