Proton magnetic resonance spectroscopy of brain tumors: an in vitro study

The ability of proton magnetic resonance spectroscopy (1H MRS) to diagnose brain tumors was investigated using in vitro high-resolution spectra. Fifty-eight surgically excised samples of brain tumors (12 glioblastomas, 4 anaplastic astrocytomas, 6 astrocytomas, 12 meningiomas, 6 neurinomas, 4 chordomas, 3 craniopharyngiomas, 2 pituitary adenomas, 2 malignant lymphomas, 1 ependymoma, 1 medulloblastoma, and metastatic brain tumors including 3 pulmonary adenocarcinomas, a hepatocellular carcinoma, and a renal cell carcinoma) and 4 nontumorous lobectomized brains were examined by in vitro 1H MRS. N-Acetyl-aspartate was demonstrated in normal tissues but could not be detected in nonneuroectodermal tumors. Total creatine was decreased in all brain tumors in comparison with normal brain tissues, but was relatively higher in neuroectodermal tumors than in other brain tumors. Choline-containing compounds were present in all tumors except craniopharyngioma, and their concentrations were particularly high in a metastatic brain tumor from hepatocellular carcinoma. The concentration of glycine was high in neuroectodermal tumors, whereas that of taurine was high in medulloblastoma, pituitary adenoma, and renal cell carcinoma. Alanine was increased in meningioma, glioma, and pituitary adenoma. Neurinoma had the largest inositol content among the tumors examined. Thus each type of brain tumor exhibited a characteristic MR spectrum. These data suggested that in vivo 1H MRS might provide clinically useful information about tumor metabolism and aid in the differential diagnosis of tumors. Although excellent anatomical localization of tumors can be readily obtained by MR imaging, MRS may provide additional information in cases in which the differential diagnosis of tumors by MR imaging is difficult.