IN-VIVO PROTON MAGNETIC-RESONANCE SPECTROSCOPY OF ALCOHOL IN RHESUS-MONKEY BRAIN

Brain alcohol was measured in rhesus monkeys (Macaca mulatta) by proto n magnetic resonance spectroscopy (MRS) following acute nasogastric al cohol administration (0.8 g/kg). Monkeys were anesthetized with ketami ne and xylazine. A 1.5 T whole body imager and a 3-inch surface coil w ere used to acquire TE 30 and 270 ms spectra from a 7.5 cc voxel local ized with a stimulated echo (STEAM) sequence. Venous blood samples wer e collected during spectral acquisitions for gas chromatographic deter mination of temporally concordant blood alcohol levels (BALs). Acute a lcohol administration did not alter the resonance areas of N-acetylasp artate/N-acetyl containing compounds (NAA), choline containing compoun ds, or total creatine. The NAA resonance was used as an internal stand ard to calculate approximate brain alcohol concentrations, which avera ged 27 +/- 3% and 27 +/- 8% of temporally concordant BALs (T-2-correct ed TE 30 and TE 270 ms spectra, respectively). In addition to reconfir ming results from prior studies finding incomplete detection of brain alcohol with MRS, these results demonstrate the feasibility of measuri ng brain alcohol in anesthetized nonhuman primates to examine relation ships between alcohol exposure history and MRS-visibility of brain alc ohol.