Positron emission tomographic study of suppression of gray-matter glucose utilization by brain tumors

Positron emission tomography (PET) scanning with [18F]-2-fluoro-2-deoxy-D-glucose (FDG) was used to study 59 patients with astrocytomas and three patients with other cerebral mass lesions. Suppression of gray-matter glucose utilization ranging from 8% to 64% (mean, 30%) was seen in 92% of cases. Three categories of suppression were apparent, with the greatest degrees of suppression occurring in edematous gray matter adjacent to mass lesions. Lesser degrees of suppression were noted in nonedematous structures (normal attenuation on computed tomographic scan) adjacent to the lesion. Significant suppression was also present in gray matter spatially remote from but functionally linked to the site of the lesion. This approach may become a useful tool for improved understanding of the clinical presentation of certain pathologic entities and for evaluation of disease progression and response to treatment.