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Implementation and validation of localized constant‐time correlated spectroscopy (LCT‐COSY) on a clinical 3T MRI scanner for investigation of muscle metabolism
Author(s) -
Velan S. Sendhil,
Ramamurthy Senthil,
Ainala Srilatha,
Durst Christopher,
Lemieux Susan K.,
Raylman Raymond R.,
Spencer Richard G.,
Thomas M. Albert
Publication year - 2007
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.20990
Subject(s) - homonuclear molecule , nuclear magnetic resonance , in vivo , scanner , nuclear magnetic resonance spectroscopy , pulse sequence , spectroscopy , chemistry , imaging phantom , spectral line , materials science , physics , analytical chemistry (journal) , optics , chromatography , biology , microbiology and biotechnology , organic chemistry , quantum mechanics , astronomy , molecule
Purpose To implement and evaluate a novel single‐volume two‐dimensional localized constant‐time‐based correlated spectroscopy (2D LCT‐COSY) sequence on a clinical 3T MR scanner. This sequence exhibits homonuclear decoupling along the F1 dimension, leading to improved spectral resolution compared to that of non‐constant‐time localized correlated spectroscopy (L–COSY). Materials and Methods A GE 3T MR scanner equipped with a quadrature transmit and receive extremity coil was used in this study. The 2D LCT‐COSY sequence was programmed using General Electric's EPIC compiler. Simulations for a two‐spin 1/2 system were performed using GAMMA libraries to evaluate the theoretical performance of the sequences, and were also compared with corresponding phantom experiments using trans‐cinnamic acid. Finally, spectra were acquired from the soleus muscle of healthy volunteers in order to evaluate performance in vivo. Results Simulations and experimental results confirmed the improved spectral resolution of LCT‐COSY over L–COSY, as well as its homonuclear decoupling performance. The behavior of resonance amplitudes as a function of evolution time in the experiment also was appropriately reflected by the simulation. Corresponding results were obtained for the in vivo muscle spectra, in which separation of overlapping olefinic and allylic methylene protons from the intra‐ and extramyocellular lipids (IMCL and EMCL, respectively) was achieved. Conclusion Simulations and experimental results in vitro and in vivo demonstrate the strengths of LCT‐COSY. This technique can be implemented on systems of any field strength, and has the potential to separate overlapping metabolites in tissue when employed on high‐field clinical MRI scanners equipped for proton spectroscopy. J. Magn. Reson. Imaging 2007;26:410–417. © 2007 Wiley‐Liss, Inc.