Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0017638 (glioma)
 30,880 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Surface coil MRI combined with spatially localized spectroscopy was used to noninvasively detect 1H signals from metabolites within an intracerebral malignant glioma in rats. The MRS pulse sequence was based upon two-dimensional ISIS, which restricted 1H signals to a column-shaped volume, combined with one-dimensional spectroscopic imaging, which further resolved the signals into 8 or 16 slices along the major axis of the column. All experiments were executed with adiabatic pulses which induced uniform spin excitation despite the inhomogeneous radiofrequency field distribution produced by the surface coil transmitter. Surface coil MRI and MRS experiments were performed on phantom samples, normal rat brains, and rat brains harboring malignant gliomas. Spatially resolved in vivo 1H spectra of intracerebral gliomas revealed significantly decreased concentrations of N-acetyl-aspartate and creatine and increased lactic acid (or lipids) as compared to the contralateral hemisphere. These results demonstrate that metabolic abnormalities in intracerebral rat gliomas can be spatially resolved in a noninvasive manner using localized in vivo 1H MRS.
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PMID:Spatially localized in vivo 1H magnetic resonance spectroscopy of an intracerebral rat glioma. 173 86

Glioma are often histologically heterogenous. As many of these tumors are not removable in toto, due to their localisation, the most malignant part of the tumor may be missed and information for optimum therapeutic management is incomplete. Furthermore, low grade gliomas tend to become more malignant in their development; additional surgical intervention is often not possible. Non-invasive measurement of tumor glucose metabolism with (F-18)-2-fluoro-2-deoxyglucose (FDG) and positron-emission-tomography (PET) may be used to evaluate tumor malignancy. Malignant gliomas (astrocytoma III degree and glioblastoma) frequently showed increased peak metabolic rates (in comparison with normal white matter) and uncoupling of FDG transport and phosphorylation. Preliminary experiences with image-guided localized phosphorus-31 MR spectroscopy (P-31 MRS) demonstrated a decrease of phosphodiesters in malignant gliomas, whereas the phosphomonoesters showed an increase in several cases. The phosphocreatine peak was often reduced. A more active therapy of low grade gliomas might be indicated when signs of hypermetabolism in FDG-PET and alteration of energy-rich phosphates or membrane-phosphates in P-31 MRS are found.
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PMID:[Metabolic studies of gliomas with positron emission tomography and phosphorus 31 MR spectroscopy in diagnosis and treatment planning]. 268 95

High-resolution 1H surface coil NMR spectroscopy (MRS) was used to evaluate in vivo the cerebral metabolism changes in rat brain induced by a glial tumor growing in situ. Tumor cells (C6 glioma cells) were stereotaxically placed in the right hemisphere superficially. 1H MRS was performed using 5-mm surface coils implanted over the right hemisphere and the water was suppressed using a binomial sequence. As the intracerebral tumor size increased, there was a marked decrease in the N-acetyl aspartate level and an increase in the 1.3 ppm peak. Edition of this peak showed that lactate increased but lipids increased much more than lactate. Moreover the ratio between the choline-phosphocholine and creatine-phosphocreatine peaks changed. This study demonstrates that high-resolution surface coil 1H MRS can be used to monitor changes in metabolism associated with growth of an experimentally induced rat brain tumor in situ.
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PMID:In vivo 1H NMR spectroscopy of an intracerebral glioma in the rat. 271 5

Several multi-dimensional statistical evaluation methods were applied to single-voxel proton MR spectra of glial brain tumors and of healthy volunteers. Metabolic coordinates with histological relevance for future diagnosis were found by which spectra from controls, low-grade tumors, and high-grade tumors were completely separated. Significant differences between low-grade and high-grade glioma patients and controls were found for several metabolic ratios by variance analysis. Cluster analysis both with and without principal component analysis was applied. The outcome of these two approaches depended mainly on the lipid-to-creatine ratio. Two other approaches, discriminant factor analysis and the orthonormal discriminant vector method were then used to find discriminatory metabolic coordinates. It turned out that a linear combination of all evaluable metabolic ratios made it possible to separate the three groups completely. On the basis of these results, a classification method that uses the entire proton MRS spectrum is proposed.
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PMID:In vivo proton MR spectroscopy of human gliomas: definition of metabolic coordinates for multi-dimensional classification. 747 84

We studied the feasibility of characterizing brain tumor tissue by localized proton magnetic resonance spectroscopy (1H-MRS). Twenty-six newly diagnosed tumors were examined by in-vivo 1H-MRS. The NAA (N-acetylaspartate)/Cho (choline) ratio of Grade 2 astrocytoma was higher than that of Grade 4. The Cho/Cr (creatine and phosphocreatine) ratio of meningioma was considerably higher than that of glioma of all grades. We have experienced only two cases of ependymoma and the Cho/Cr ratios of both were lower than that of glioma. It seems likely that 1H-MRS can be used to differentiate Grade 2 from Grade 4 in most cases of astrocytoma based on the NAA/Cho ratio, though a few cases will overlap. Meningioma can be distinguished easily from glioma, and the results of our study suggest that ependymoma shows a characteristic pattern on 1H-MRS, different from those of other brain tumors.
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PMID:Non-invasive characterization of brain tumor by in-vivo proton magnetic resonance spectroscopy. 774 4

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.
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PMID:Proton magnetic resonance spectroscopy of brain tumors: an in vitro study. 780 3

In vivo 1H MRS can be used to detect and quantify the lactate resonance at 1.3 ppm provided that overlapping lipid resonances are eliminated. A homonuclear spectral editing method was developed to acquire uncontaminated 1H spectra of lactate with adiabatic pulses. An advantage of the adiabatic pulse sequence is the ability to induce uniform flip angles and to maximize sensitivity in applications employing surface coil transmitters which produce highly inhomogeneous B1. Glycolytic activity in an intracerebral C6 glioma in rats was monitored by using adiabatic editing sequences to observe [3-13C]lactate produced from infused [1-13C]glucose. Acute hyperglycemia (serum glucose > 22 mM, n = 10) had no significant effect (P = 0.08) on the total ([12C] + [13C]) tumor lactate signal intensity.
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PMID:Localized detection of glioma glycolysis using edited 1H MRS. 837 70

Proton magnetic resonance spectroscopy (1H MRS) was evaluated for distinguishing between radiation necrosis and recurrent glioma in 11 patients after high-dose radiotherapy. Six patients had a histological diagnosis of recurrent glioma. Four patients had a histological diagnosis of radiation necrosis and one had a clinical course consistent with the diagnosis of radiation necrosis. 1H MRS showed cases of radiation necrosis had two characteristic 1H MRS patterns: markedly increased lactate/creatine and phosphocreatine (Cr) ratio and decreased choline-containing compounds/Cr ratio compared to that of recurrent glioma; or all the major metabolites were completely diminished. The N-acetyl aspartate signal was not helpful for differential diagnosis. 1H MRS is a potentially useful method for differentiating tumor recurrence from radiation necrosis in patients treated for malignant glioma.
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PMID:Differentiation of cerebral radiation necrosis from tumor recurrence by proton magnetic resonance spectroscopy. 909 25

Water-soluble metabolites extracted from 60 surgically excised samples of various brain tumors and four nontumorous lobectomized brains were measured quantitatively using in vitro high-resolution magnetic resonance spectroscopy. A detailed MR spectrum-histology correlation study in a glioblastoma was made, to reveal MR spectral changes in accordance with the density of glioma cells. Furthermore, three cases that had difficult preoperative diagnoses are discussed. MR spectra from gliomas exhibited characteristic patterns according to malignancy, presumably reflecting its metabolic effects. Concentrations of choline-containing compounds, inositol, alanine, glycine and phosphorylethanolamine (PEA) increased according to the degree of malignancy, but it was noteworthy that in glioblastoma the choline-containing compounds, inositol, alanine, glycine and phosphorylethanolamine increased according to the degree of malignancy. In particular, the glycine concentration was very high in glioblastoma. We also detected a large amount of taurine in medulloblastoma. Although the total creatine concentrations decreased according to the malignancy, the concentration of total creatine was relatively preserved in neuroectodermal tumors but was low in nonneuroectodermal tumors. N-acetyl-aspartate was unequivocally demonstrated in normal tissues, but could not be detected in nonneuroectodermal brain tumors such as metastatic brain tumor, meningioma, neurinoma and chordoma. In meningioma, although a high peak of choline-containing compounds has been reported uniquely by in vitro and in vivo 1H-MRS, we demonstrated that its concentration was not increased in meningioma; instead, there was an increased alanine content. 1H-MRS of neurinoma demonstrated high inositol peaks, and a large amount of inositol. The reason for the high inositol content in neurinoma is unknown, but the prominent peak of inositol on MR spectra should be useful for the differential diagnosis of neurinoma from meningioma. PEA concentration was increased four to five times in pituitary adenoma, malignant lymphoma, and medulloblastoma as compared with normal brain. Thus 1H-MRS might provide clinically useful information on tumor malignancy and characteristic tumor metabolism. Although excellent anatomical information of tumors can be readily obtained by magnetic resonance imaging. MRS provides metabolic information. MRS may provide additional information in cases in which the differential diagnosis of tumors by neuroimaging is difficult.
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PMID:Absolute concentrations of metabolites in human brain tumors using in vitro proton magnetic resonance spectroscopy. 925 Nov 9

The annual incidence of primary central nervous system tumors, including gliomas, is increasing, however, the prognosis of these tumors remains poor with a median survival of only 5 years. The imaging of tumors by computerised tomography, magnetic resonance imaging and newer methods such as positron emission tomography and proton magnetic resonance spectroscopy (1H-MRS) is increasing our knowledge of tumor biology and extent of the disease. Advances within the field of neurosurgery have improved operative procedures reducing mortality and morbidity. Furthermore, radiotherapy planning, tumor targeting and repositioning for treatment have all improved initial tumor management. The role of adjuvant chemotherapy remains controversial. Chemotherapy for advanced and recurrent disease has been extensively investigated, and although improvements in quality of life have been recorded, no prolongation of survival has been documented. With new discoveries and increasing knowledge of the physiology and molecular biology of these tumors the potential for targeting therapy at a genetic level is becoming increasingly promising. This review provides an overview of these current perspectives in glioma management.
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PMID:Current perspectives in gliomas. 933 Feb 70


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