Chemical exchange magnetic resonance imaging (CHEMI).
Systems investigated with NMR spectroscopy are sometimes heterogeneous with respect to chemical composition, rates of chemical exchange, and other properties influencing magnetic resonance parameters. A method was developed to spatially encode reaction kinetic information and produce NMR images sensitive to chemical exchange. A modified spin-echo pulse sequence was used to allow chemical shift-selective imaging and chemical exchange encoding. 1H and 31P images with microscopic resolution were obtained which yielded chemical exchange as a function of position. Chemical exchange images of the base-catalyzed proton exchange of acetylacetone and of the enzyme-catalyzed 31P transfer between PCr and ATP were obtained at 8.4 T in phantoms at 360 and 146 MHz, respectively. These images demonstrate a means of investigating kinetic heterogeneity and compartmentalization of reactions that are important in the study of both living and non-living systems.
McFarland
E W
EW
Francis Bitter National Magnet Laboratory, Massachusetts Institute of Technology, Cambridge 02139.
Neuringer
L J
LJ
Kushmerick
M J
MJ
D000255:Adenosine Triphosphate; D000818:Animals; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003402:Creatine Kinase; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation / Q000379:methods*; D008853:Microscopy / Q000295:instrumentation / Q000379:methods; D008961:Models, Structural; D008967:Molecular Biology; D010725:Phosphocreatine; D011522:Protons; D011894:Rana pipiens / Q000196:embryology
D011522:Protons; D010725:Phosphocreatine; D000255:Adenosine Triphosphate; D003402:Creatine Kinase