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One‐dimensional image‐selected in vivo spectroscopy localized phosphorus saturation transfer at 7T
Author(s) -
Valkovič Ladislav,
Bogner Wolfgang,
Gajdošík Martin,
Považan Michal,
Kukurová Ivica Just,
Krššák Martin,
Gruber Stephan,
Frollo Ivan,
Trattnig Siegfried,
Chmelík Marek
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.25058
Subject(s) - phosphocreatine , in vivo , chemistry , pi , adenosine triphosphate , nuclear magnetic resonance , nuclear magnetic resonance spectroscopy , analytical chemistry (journal) , energy metabolism , biochemistry , biology , endocrinology , stereochemistry , chromatography , physics , microbiology and biotechnology
Purpose To evaluate the feasibility of a one‐dimensional image‐selected in vivo spectroscopy (1D‐ISIS) saturation transfer (ST) sequence at 7T for localized in vivo measurements of energy metabolism in different tissues in clinically reasonable examination times. Methods The performance of a gradient offset independent adiabacity‐based 1D‐ISIS localization was tested on phantom and the localized ST sequence was compared with the nonlocalized version in vivo. We performed localized measurements of basal metabolism of human liver and different muscle groups of the calf. Localized ST experiments took 15–25 minutes. Results The selectivity of the 1D‐ISIS sequence was 81.63% and the outer volume suppression was 97.57%. The ST parameters acquired with the 1D‐ISIS sequence and with the nonlocalized acquisition in the muscle were not statistically different. The forward rate constants for phosphocreatine (PCr)–adenosine triphosphate (ATP) and inorganic phosphate (Pi)–ATP exchange reactions were measured in the soleus (k CK = 0.30 ± 0.06 s −1 and k ATP = 0.11 ± 0.02 s −1 , respectively) and in the medial gastrocnemius (k CK = 0.27 ± 0.06 s −1 and k ATP = 0.09 ± 0.03s −1 , respectively) in 15 minutes per muscle group. The corresponding fluxes were F CK = 6.26 ± 1.28 μmol/g/s, F ATP = 0.22 ± 0.05 μmol/g/s and F CK = 6.29 ± 1.66 μmol/g/s, F ATP = 0.21 ± 0.07 μmol/g/s, for soleus and gastrocnemius, respectively. The hepatic ATP synthesis measurement was feasible in 24 minutes. Conclusion The fast assessment of PCr–ATP and Pi–ATP exchange rates at 7T makes the 1D‐ISIS ST sequence a promising tool for examining local resting‐state metabolism in clinically acceptable measurement times. Magn Reson Med 72:1509–1515, 2014. © 2014 Wiley Periodicals, Inc.