title: Dynamic positron tomographic imaging with nitrogen-13 glutamate in patients with coronary artery disease: comparison with nitrogen-13 ammonia and fluorine-18 fluorodeoxyglucose imaging.
abstract: This study was designed to test the usefulness of nitrogen-13 (N-13) glutamate imaging with positron emission tomography in defining myocardial ischemia in humans. Seventeen patients who had undergone coronary arteriography were studied with N-13 glutamate at peak supine exercise using a bicycle ergometer, as well as with the flow tracer N-13 ammonia at peak exercise during a second similar exercise test. Six of the patients also underwent imaging with N-13 glutamate at rest before exercise testing; in the remaining 11 patients imaging with fluorine-18 (F-18) fluorodeoxyglucose was performed to assess glucose metabolism after the second exercise test. Seven patients had classic metabolism-flow mismatches consistent with ischemia (that is, decreased N-13 ammonia uptake in a region with relatively increased F-18 fluorodeoxyglucose uptake). There was no evidence of increased N-13 glutamate uptake in the ischemic mismatched regions in any of these patients. In all 17 patients, the uptake of N-13 glutamate during exercise paralleled the uptake of N-13 ammonia during exercise, suggesting that N-13 glutamate behaves as a flow tracer rather than as a metabolic marker of ischemia in humans.
authors.affiliation: Department of Medicine, University of California, Los Angeles School of Medicine 90024-1679.
authors.forename: J
authors.initials: J
authors.lastname: Krivokapich
authors.forename: J R
authors.initials: JR
authors.lastname: Barrio
authors.forename: S C
authors.initials: SC
authors.lastname: Huang
authors.forename: H R
authors.initials: HR
authors.lastname: Schelbert
mesh_terms: D000368:Aged; D000641:Ammonia; D003326:Coronary Circulation / Q000502:physiology; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D003847:Deoxyglucose / Q000031:analogs & derivatives*; D005080:Exercise Test; D005260:Female; D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D005971:Glutamates; D018698:Glutamic Acid; D006321:Heart / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D009590:Nitrogen Radioisotopes; D014055:Tomography, Emission-Computed
chemical_list: D005462:Fluorine Radioisotopes; D005971:Glutamates; D009590:Nitrogen Radioisotopes; D019788:Fluorodeoxyglucose F18; D018698:Glutamic Acid; D000641:Ammonia; D003847:Deoxyglucose