Optimal cutoff levels of F-18 fluorodeoxyglucose uptake in the differentiation of low-grade from high-grade brain tumors with PET.
OBJECTIVE
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).


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.


CONCLUSIONS
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.
Delbeke
D
D
Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN 37232-2675.
Meyerowitz
C
C
Lapidus
R L
RL
Maciunas
R J
RJ
Jennings
M T
MT
Moots
P L
PL
Kessler
R M
RM
D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D003847:Deoxyglucose / Q000031:analogs & derivatives*; D003937:Diagnosis, Differential; D005260:Female; D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D005910:Glioma / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014055:Tomography, Emission-Computed; D014057:Tomography, X-Ray Computed
D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D003847:Deoxyglucose