Open AccessCreatine kinase rate constant in the human heart at 7T with 1D-ISIS/2D CSI localization
Author(s) -
Adil Bashir,
Jianyi Zhang,
Thomas S. Denney
Publication year - 2020
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0229933
Subject(s) - creatine kinase , constant (computer programming) , nuclear magnetic resonance , physics , medicine , cardiology , computer science , programming language
Purpose Creatine Kinase (CK) reaction plays an important role in energy metabolism and estimate of its reaction rate constant in heart provides important insight into cardiac energetics. Fast saturation transfer method (T 1 n o m – T 1nominal) to measure CK reaction rate constant ( k f ) was previously demonstrated in open chest swine hearts. The goal of this work is to further develop this method for measuring the k f in human myocardium at 7T.T 1 n o mapproach is combined with 1D-ISIS/2D-CSI for in vivo spatial localization and myocardial CK forward rate constant was then measured in 7 volunteers at 7T. MethodsT 1 n o mmethod uses two partially relaxed saturation transfer (ST) spectra and correction factor to determine CK rate constant. Correction factor is determined by numerical simulation of Bloch McConnell equations using known spin and experimental parameters. Optimal parameters and error estimate in calculation of CK reaction rate constant were determined by simulations. The technique was validated in calf muscles by direct comparison with saturation transfer measurements.T 1 n o mpulse sequence was incorporated with 1D-image selected in vivo spectroscopy, combined with 2D-chemical shift spectroscopic imaging (1D-ISIS/2D-CSI) for studies in heart. The myocardial CK reaction rate constant was then measured in 7 volunteers. Results Skeletal muscle k f determined by conventional approach andT 1 n o mapproach were the same 0.31 ± 0.02 s -1 and 0.30 ± 0.04 s -1 demonstrating the validity of the technique. Results are reported as mean ± SD. Myocardial CK reaction rate constant was 0.29 ± 0.05 s -1 , consistent with previously reported studies. ConclusionT 1 n o mmethod enables acquisition of 31 P saturation transfer MRS under partially relaxed conditions and enables 2D-CSI of k f in myocardium. This work enables applications for in vivo CSI imaging of energetics in heart and other organs in clinically relevant acquisition time.