31 P NMR spectroscopy of the stomach by zig–zag coil

Phosphorus‐31 ( 31 P) nuclear magnetic resonance (NMR) spectroscopic investigations of the rat stomach were performed utilizing a 1‐cm 2 , three‐turn, zig‐zag coil. A zig‐zag coil of this dimension produced an effective B l field that extends only within a 4‐mm distance from the plane of the surface coil, rendering it possible to obtain high‐resolution 31 P spectra localized to the stomach without contamination from surrounding tissues. Normal stomach showed a characteristic spectral pattern with resonances reflecting inorganic phosphate ( P i ), phosphocreatine (PCr), and the α‐, β‐, and γ‐phosphates of adenosine triphosphate (ATP). Ischemia‐induced changes in P i , PCr, and ATP resonances were readily followed in vivo with a time resolution of 2.13 min. Indomethacin‐induced ulcer revealed a low intracellular pH and a decrease in the PCr to P i ratio indicating the partially ischemic conditions of ulcerative lesions of the stomach as has been previously suggested. The present studies indicate that 31 P NMR spectroscopy utilizing a zig‐zag coil is a powerful tool to study local pathology of the gastrointestinal (GI) tract. Since zig‐zag coils suitable for fiberscopic devices are easily constructed, clinical applications of the present technique are apparent. © Academic Press, Inc.