O-17-decoupled proton MR spectroscopy and imaging with a double-tuned
radiofrequency (RF) coil at 2 T was used to detect and quantify H-2 O-
17 in tissue phantoms containing various concentrations of O-17-enrich
ed water in 5% gelatin. The pulse sequence used in these experiments c
onsisted of a conventional proton spin-echo sequence with RF irradiati
on at the O-17 resonance frequency applied between the proton 90 degre
es pulse and the signal acquisition window. The double-tuned coil prov
ided several advantages over systems using separate RF coils for O-17
decoupling and proton excitation/detection, including ensuring that th
e same (or similar) sample volumes are excited and decoupled and permi
tting accurate calibration of the O-17 decoupling pulse amplitude, The
efficiency of O-17 decoupling as a function of decoupling RF amplitud
e, decoupling duration, and decoupling resonance offset was investigat
ed, Finally, the specific absorption rate of the O-17 decoupled pulse
sequence was investigated and found to lie within federal guidelines a
t 1.5 T. Copyright (C) 1996 Elsevier Science inc.