Small gliomas: metabolism and blood flow.

Eight patients with small gliomas (6 low-grade and 2 high-grade) localized in a single gyrus or less than 2 cm diameter were investigated using positron emission tomography and single photon emission computed tomography. All three tumors examined demonstrated hypermetabolism of amino acids. High-grade gliomas demonstrated hypermetabolism of glucose and high blood flow, but normal or low oxygen metabolism. High-grade gliomas also showed accumulation of 201Tl chloride and high or low accumulation of 123I-isopropyl iodoamphetamine. These indications allow preoperative diagnosis of the malignancy of small gliomas, which is important because small gliomas with high-grade malignancy need more extensive removal and adjuvant therapy.