Preoperative Grading of Glioma Ma Single-Photon Emission CT: Compa I

evaluated by means of thallium-201 scintigraphy. The results indicate a need for caution when requent stic as-gliomas Kerno-ion CT omising ment of by ma-ique is perative racy is ical dif-n high-gliomas s tumor alateral e is notinterpreting findings on images obtained with thallium-201 single-photon emission CT in preop-erative evaluation of brain tumors. Index terms: Brain neoplasms, computed tomography; Glioma; Single-photon emission computed tomography AJNR Am J Neuroradiol 17:925–932, May 1996 In the treatment of gliomas it is essential to define accurately the grade of malignancy, since the approach differs for low-grade and high-grade gliomas. Diagnostic procedures cur-rently used include computed tomography (CT) or magnetic resonance (MR) imaging followed by tumor resection or brain biopsy and histo-logic staging. The imaging characteristics seen on CT scans enable tumor staging to some ex-tent (1). Damage to the blood-brain barrier is considered a reliable marker of high-grade ma-lignancy, but as stated by Chamberlain et al (2), nonenhancing tumors are rather f among the moderately malignant anapla trocytomas (ie, high-grade malignant as defined histologically, also known as han grade III gliomas). Thallium-201 single-photon emiss (SPECT) has been introduced as a pr diagnostic tool for guiding the manage gliomas, because thallium is taken up lignant glioma cells (3, 4). This techn also said to be an instrument in preo assessment, since its prediction accu high (89%), and there is a strong statist ference between the thallium index i grade gliomas versus that in low-grade (5, 6) (the thallium index is defined a uptake relative to the uptake in the contr hemisphere). Since thallium-201 upta