High‐resolution one‐and two‐dimensional ¹H MRS of human brain tumor and normal glial cells

Abstract

Astrocytoma (WHO grade II, III), glioblastoma, malignant melanoma, and normal glial cell cultures, established from biopsies, were investigated by 1H MRS. At a 1H resonance frequency of 500 MHz (11.75 T) a high spectral resolution was achieved in 1D 1H spectra; in conjunction with 2D shift-correlated (COSY) MRS, resonances of alanine, aspartate, choline, creatine, glutamate, glutamine, hypotaurine, myo-inositol, phosphocreatine, phosphoryl-ethanolamine, phosphoryl-choline, lactate, lysine, N-acetylaspartate, taurine, threonine and valine could be identified. T1 relaxation times for the most prominent compounds are presented. T1 values of lactate ranged between 450 ms and 850 ms. The intensity of the lactate signal revealed differences between individual spectra, but exhibited no correlation between different tumor specimens or degree of malignancy. It was shown that the lactate signal at 1.3 ppm is covered by peaks arising from threonine and fatty acids. The choline signal level varied among spectra of different tumors, among tumors with similar degree of malignancy, and within the same tumor. Further preliminary differences due to aspartate, inositol and glutamine/glutamate were found in 1D and 2D COSY spectra between normal glial cells as well as different tumors. These results indicate that some differences observed in in vivo spectra may be attributable to secondary macroscopic structural changes (hypoxia, necrosis) and not to tumor inherent characteristics. Further correlation between in vivo and in vitro spectroscopy is therefore required.

Untreated Glioblastoma Multiforme: IncreasedMyo-inositol and Glutamine Levels in the Contralateral Cerebral Hemisphere at Proton MR Spectroscopy

“…Furthermore, it has been hypothesized that glutamine serves as an energy fuel through glutaminolysis (25), which seems to be a prerequisite for tumor cell growth (26). Accordingly, an increased glutamine level in gliomas has also been demonstrated by using highresolution proton MR spectroscopy of tumor cells in vitro (9,27) and has even led to the description of gliomas as "glutamine traps" (28).…”

Proton spectral editing for discrimination of lactate and threonine 1.31 ppm resonances in human brain in vivo

“…Threonine (Thr) is present in autopsied human brain tissue (7) and has been detected in rat brain (8,9) and human brain (10) by 1 H MRS. Thr has five water nonexchangeable protons from a methyl group and two methine groups, forming an A 3 MX spin system, where A, M, and X spins resonate at 1.31, 4.25, and 3.58 ppm, respectively, with coupling strengths J AM ϭ 6.35 Hz and J MX ϭ 4.92 Hz (1). Because of the close proximity of the A-spin resonances of Lac and Thr, detection of the signal at 1.31 ppm by conventional MRS always records an overlap of Lac and Thr, as illustrated in Fig.…”

Effect of Paraquat and Amyloid-β-Peptide on the Metabolism in Primary Astrocytes Studied by 1H-NMR

“…Lactate is normally characterized by a resonance at =1.33 ppm. However, this signal coincides with those of threonine and fatty acids [53,54]. Therefore, the estimations of lactate here is based only on its methine proton at =4.11 ppm.…”