[Kinetic analysis of glucose metabolism in meningiomas--comparison with malignant gliomas]

We measured kinetic rate constants and glucose metabolic rate (kinetic-rCMRGl) using dynamic positron emission tomography (PET), as well as regional cerebral blood flow (rCBF), blood volume (rCBV), oxygen extraction fraction (rOEF), oxygen metabolic rate (rCMRO2) and autoradiographic rCMRGl (arg-rCMRGl), in patients with meningioma. Ten patients including one recurrent case, two males and eight females aged from 44 to 71 years with a mean age of 54 years old, were studied prior to surgical interventions. Histological diagnosis was as follows: seven cases of meningothelial type, two cases of angiomatous type and one fibrous type. For quantitative analysis, regions of interest (ROI) on PET images were delineated on the tumor and the contralateral gray matter in comparison with eight cases with malignant gliomas (five cases of malignant astrocytoma and three cases of glioblastoma, aged from 14 to 70 years with a mean age of 41 years old). Hemocirculation of the tumor was exceedingly higher than that of the contralateral gray matter, which corresponded to neuroradiological findings of abundant tumor vessels. Low rOEF implicated an excessive blood flow beyond oxygen demand of the tumor. The raised metabolic rate (rCMRO2/rCMRGl) suggested rather aerobic glycolysis as compared with malignant gliomas. The kinetic rate constants of tracer transport from blood to brain (k1), reverse transport from brain to blood (k2), and phosphorylation (k3) were analyzed according to the three compartment model of 18F-fluorodeoxyglucose (FDG). Tumor k1 and k2 values markedly increased in all examined cases, suggesting high permeability due to lack of blood-brain barrier and an abundant blood supply.(ABSTRACT TRUNCATED AT 250 WORDS)