Analysis with NMR localized spectroscopy of rat brainin vivo andex vivo

The volume-selected MRS of rat brain was performed on a 200 MHz broad horizontal-bore nuclear magnetic resonance imaging spectromete;. The localized proton spectroscopy of rat brain was acquired using the double spin-echo pulse sequence (PRESS) to select the position and size of the volume. Water signal was suppressed by CHESS sequence which was composed of chemical shift selective rf pulses and dephasing gradients. The parameterTE was taken as 40 ms and 135 ms in the experiment. The localized MRS of the rat brain with the status of live and death was obtained in variousTE values. Results showed that volume-selected proton MRS of the rat brainin vivo with longerTE consisted mainly of signals produced by N-acetylaspartate (NAA), creatine (Cre), choline (Cho) and the lactate spectral peak occurred in the MRS of the rat brainex vivo. On the other hand, the MRS of the rat brain with shorterTE contained glutamine/glutamate and lipid signals besides those signals mentioned previously. Although the information abstracted from the MRS of the rat brain with shorterTE may be more than that with longerTE, the spectral resolution of the MRS with shorterTE was slightly worse. In addition, it might indicate that the absolute concentration of NAA was decreased in dead rat brain because the SNR of NAA peak in the MRSex vivo got lower.