FDG PET/CT Assessment of the Biological Behavior of Meningiomas

ABSTRACT

OBJECTIVE: We investigated the pattern of glucose uptake in meningiomas using (18)F-fluoro-2-deoxy-D-glucose(FDG) PET/CT. It was hypothesized that the degree of glucose uptake in each tumor could predict the histologic grade. METHODS: In 19 patients with meningiomas, the Ki-67 proliferative index, standardized uptake values(SUV) of FDG uptake, tumor to contralateral gray matter ratio(TGR) of SUV, tumor size, edema grade, vascular endothelial growth factor(VEGF) expression, histopathologic grade and the blood supply pattern were assessed. RESULTS: Of the 19 meningiomas, 8 were meningothelial, 1 fibrous, 2 transitional, 1 psammomatous, 2 angiomatous, and 5 atypical. The tumor proliferative index of Ki-67, tumor size, and peritumoral edema were larger in the histopathologic grade-2 meninigiomas than in the grade-1 meningioma group. There were no significant differences in SUV and TGR between two groups. Tumor size and peritumoral edema were significantly larger in VEGF-positive tumors than in negative tumors. Conventional angiography was performed in 12 patients. Dural supply was noted predominantly in 2 patients. Four patients had mainly pial cortical supply patterns. In tumors with more pial supply, VEGF was more frequently positive. There was a significant relation between SUV and Ki-67 and between SUV and peritumoral edema. CONCLUSION: We found FDG uptake in meningiomas is associated with proliferative potential, however, no clear limits of SUV and TGR can be set to distinguish between grade-1 and grade-2 meningiomas, which makes the assessment of malignancy grade using PET scan metabolic imaging difficult in individual cases.