In vivo carbon-edited detection with proton echo-planar spectroscopic imaging (ICED PEPSI): [3,4-(13)CH(2)]glutamate/glutamine tomography in rat brain.
A method for in vivo carbon-edited detection with proton echo-planar spectroscopic imaging (ICED PEPSI) is described. This method is composed of an echo-planar based acquisition implemented with (13)C-(1)H J editing spectroscopy and is intended for high temporal and spatial resolution in vivo spectroscopic imaging of (13)C turnover, from D-[1,6-(13)C]glucose to glutamate and glutamine, in the brain. At a static magnetic field strength of 7 T, both in vitro and in vivo chemical shift imaging data are presented with a spatial resolution of 8 microL (i.e., 1.25 x 1.25 x 5.00 mm(3)) and a maximum spectral bandwidth of 5.2 ppm in (1)H. Chemical shift imaging data acquired every 11 minutes allowed detection of regional [4-(13)CH(2)]glutamate turnover in rat brain. The [4-(13)CH(2)]glutamate turnover curves, which can be converted to tricarboxylic acid cycle fluxes, showed that the tricarboxylic acid cycle flux (V(TCA)) in pure gray and white matter can range from 1.2 +/- 0.2 to 0.5 +/- 0.1 micromol/g/min, respectively, for morphine-anesthetized rats. The mean cortical V(TCA) from 32 voxels of 1.0 +/- 0.3 micromol/g/min (N = 3) is in excellent agreement with previous localized measurements that have demonstrated that V(TCA) can range from 0.9-1.1 micromol/g/min under identical anesthetized conditions. Magn Reson Med 42:997-1003, 1999.
Hyder
F
F
Department of Diagnostic Radiology, Yale University, New Haven, Connecticut 06510, USA. fahmeed.hyder@yale.edu
Renken
R
R
Rothman
D L
DL
D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism*; D002952:Citric Acid Cycle; D017352:Echo-Planar Imaging / Q000379:methods*; D018698:Glutamic Acid / Q000378:metabolism; D005973:Glutamine / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
D005973:Glutamine; D018698:Glutamic Acid