Fei Du1, Wei Chen1
1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
Magnetization inversion transfer (IT) NMR approach has been used for the studies of creatine kinase (CK) in human and animals. To date, IT approach was based on the two-site chemical exchange model and ATPase reaction was ignored. However, in principle, the chemical reactions of CK and ATPase constitute a three-site chemically coupled spin system i.e. PCr&[larr]&[rarr]ATP&[larr]&[rarr]Pi. In this work, we investigated the kinetics involving PCr&[larr]&[rarr]ATP&[larr]&[rarr]Pi in the human brain at 7T using the three-site chemical exchange model with full matrix Bloch equation analysis developed by our lab, and compared the results derived from the three-site and two-site chemical exchange model, respectively. This study reveals that CK reaction can be approximately treated as a two-site chemical exchange system when the ATPase reaction pool is relatively small. However, ATPase reaction must be treated as a three-site chemical reaction system in order to accurately measure its chemical reaction fluxes in the brain.