Blood flow and metabolism of oligodendrogliomas: A positron emission tomography study with kinetic analysis of F-18-fluorodeoxyglucose

To accurately characterize the pathophysiology and proliferating activity o f oligodendrogliomas, we studied cerebral blood flow and metabolism using p ositron emission tomography (PET) in five patients with this tumor. Regiona l cerebral blood flow (rCBF), cerebral blood volume (rCBV), oxygen extracti on fraction (rOEF), and cerebral metabolic rates of oxygen (rCMRO(2)) and o f glucose (rCMRGl) were quantitatively measured in tumor lesions and the co ntralateral gray matter. rCMRGl was analyzed based on both kinetic and auto radiographic methods. Tumor rCBF and rCBV were lower than in the contralate ral gray matter in all preoperatively examined patients. Oxygen metabolism, determined by rCMRO(2) and rOEF, was consistently reduced in the tumor (rC MRO(2), P < 0.05 vs. gray matter, determined by the Student's t-test). Tumo r rCMRGl was significantly lower than the gray matter rCMRGl in both kineti c (P < 0.01) and autoradiographic (P < 0.05) analyses. Kinetic tumor rCMRGl varied between 1.22 and 4.13 mg/100 ml/min, but was lower than the gray ma tter value in all patients. Autoradiographic tumor rCMRGl, which ranged fro m 1.02 to 5.79 mg/100 ml/min, was also reduced in all tumors but one; the r emaining tumor, which had a relatively high value of autoradiographic rCMRG l (comparable to gray matter rCMRGl), infiltrated the contralateral hemisph ere through the corpus callosum, and was characterized by high cellular den sity. In one patient who suffered from tumor recurrence 8 years and 10 mont hs after initial treatment, phosphorylation constant (K3) and kinetic rCMRG l of the recurring tumor were higher than those of the original tumor. No o ther tumors have regrown or recurred during the postoperative follow-up per iods, which ranged from 22 to 130 months (median = 101 months). Circulation and metabolism measured by PET provide in vivo biological characteristics, including proliferating activity, in oligodendrogliomas.