Radiology, Vol 195, 47-52, Copyright © 1995 by Radiological Society of North America
Optimal cutoff levels of F-18 fluorodeoxyglucose uptake in the differentiation of low-grade from high-grade brain tumors with PET
D Delbeke, C Meyerowitz, RL Lapidus, RJ Maciunas, MT Jennings, PL Moots and RM Kessler
Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN 37232-2675.
PURPOSE: To determine the optimal cutoff level of fluorine-18-labeled
fluorodeoxyglucose (FDG) uptake in the differentiation of low-grade from
high-grade cerebral tumors at position emission tomography (PET). MATERIALS
AND METHODS: The authors retrospectively reviewed images from PET, magnetic
resonance imaging, and computed tomography performed in 58 consecutive
patients with histologically proved brain tumors. There were 32 high-grade
tumors (20 gliomas) and 26 low-grade tumors (18 gliomas). RESULTS: The best
cutoff level of FDG uptake ratios in the differentiation of high-grade from
low-grade tumors was 1.5 for tumor- to-white matter (T/WM) ratios and 0.6
for tumor-to-cortex (T/C) ratios. These levels were the same when only
gliomas were analyzed and when all tumors were analyzed. When a T/WM ratio
of more than 1.5 was considered indicative of a high-grade tumor, the
sensitivity and specificity were 94% and 77%, respectively. The results
were similar for the T/C ratio. CONCLUSION: Cutoff levels of 1.5 for the
T/WM FDG uptake ratio and 0.6 for the T/C ratio are useful in the
differentiation of low-grade from high-grade gliomas with PET.
