Premium
Measurement of creatine kinase reaction rate in human brain using magnetization transfer image‐selected in vivo spectroscopy (MT‐ISIS) and a volume 31 P/ 1 H radiofrequency coil in a clinical 3‐T MRI system
Author(s) -
Jeong EunKee,
Sung YoungHoon,
Kim SeongEun,
Zuo Chun,
Shi Xianfeng,
Mellon Eric A.,
Renshaw Perry F.
Publication year - 2011
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.1636
Subject(s) - magnetization transfer , creatine kinase , nuclear magnetic resonance , specific absorption rate , phosphocreatine , in vivo , in vivo magnetic resonance spectroscopy , chemistry , creatine , bioenergetics , adenosine triphosphate , human brain , ex vivo , nuclear medicine , magnetic resonance imaging , energy metabolism , biochemistry , medicine , in vitro , biology , physics , mitochondrion , neuroscience , telecommunications , microbiology and biotechnology , computer science , radiology , antenna (radio)
High‐energy phosphate metabolism, which allows the synthesis and regeneration of adenosine triphosphate (ATP), is a vital process for neuronal survival and activity. In particular, creatine kinase (CK) serves as an energy reservoir for the rapid buffering of ATP levels. Altered CK enzyme activity, reflecting compromised high‐energy phosphate metabolism or mitochondrial dysfunction in the brain, can be assessed using magnetization transfer (MT) MRS. MT 31 P MRS has been used to measure the forward CK reaction rate in animal and human brain, employing a surface radiofrequency coil. However, long acquisition times and excessive radiofrequency irradiation prevent these methods from being used routinely for clinical evaluations. In this article, a new MT 31 P MRS method is presented, which can be practically used to measure the CK forward reaction rate constant in a clinical MRI system employing a volume head 31 P coil for spatial localization, without contamination from the scalp muscle, and an acquisition time of 30 min. Other advantages associated with the method include radiofrequency homogeneity within the regions of interest of the brain using a volume coil with image‐selected in vivo spectroscopy localization, and reduction of the specific absorption rate using nonadiabatic radiofrequency pulses for MT saturation. The mean value of k f was measured as 0.320 ± 0.075 s −1 from 10 healthy volunteers with an age range of 18–40 years. These values are consistent with those obtained using earlier methods, and the technique may be used routinely to evaluate energetic processes in the brain on a clinical MRI system. Copyright © 2010 John Wiley & Sons, Ltd.