Proton decoupled fluorine nuclear magnetic resonance spectroscopy in situ

The efficacy of proton decoupling for enhancing the 19F nuclear magnetic resonance (NMR) signal-to-noise ratio and spectral resolution in the intact subject is demonstrated. A geometrically orthogonal cross-coil antenna configuration (Helmholtz pair, surface coil) is employed to provide 40 dB of isolation between the 19F observe and 1H decouple frequencies of 188 and 200 MHz, respectively. Further isolation is achieved through the use of high-quality notch filters on both observation and decoupling channels. Application of 19F-(1H) NMR spectroscopy to the study of 2-fluoro-2-deoxy-D-glucose metabolism in cerebral tissue in situ is presented. Significant improvements in sensitivity and resolution are obtained and result from both a collapse of the JFH multiple structure and a substantial positive nuclear Overhauser effect (NOE). To our knowledge, this is the first such demonstration of 1H decoupling in conjunction with 19F observation for study of the metabolism of a fluorinated compound in the living subject.