Comparison of MET-PET and FDG-PET for differentiation between benign lesions and malignant tumors of the lung.
OBJECTIVE
We retrospectively assessed and compared the usefulness of 11C-methionine (MET)-PET with that of 18F-FDG-PET for the differentiation between benign lesions and malignant tumors of the lung.


METHODS
We examined 101 patients with a suspected lung tumor including 79 patients with primary lung cancer and 22 patients with benign lesions. One hundred and forty PET studies (46 studies with MET-PET and 94 studies with FDG-PET) were performed. Both MET-PET and FDG-PET were performed on 39 patients. The MET-PET was performed 15 minutes after the administration of 67-740 MBq of MET, and FDG-PET 45 minutes after the administration of 30-437 MBq of FDG. The results were then evaluated by the standardized uptake value (SUV).


RESULTS
The MET uptake in lung cancer was 3.69+/-1.22 (n = 37) which was significantly higher than that in benign lesions 1.81+/-1.04 (n = 9) (p < 0.001). The sensitivity, specificity and accuracy of MET-PET were 83.8%, 88.9% and 84.8%, respectively, when 2.66 of SUV was used as the cutoff value. The FDG uptake in lung cancer was 5.94+/-2.89 (n = 75) and was also significantly larger than that in benign lesions 2.46+/-1.01 (n = 19) (p < 0.001). The sensitivity, specificity and accuracy of FDG-PET were 81.3%, 78.9% and 80.9%, respectively (cutoff = 3.20). The MET uptake in the lesions correlated significantly with FDG uptake (r = 0.71, p < 0.001). According to an ROC analysis, the area under the curve for MET-PET (area = 0. 833) was higher than that for FDG-PET (area = 0.828), but the difference was not statistically significant. Furthermore, the combined use of MET-PET and FDG-PET did not improve the diagnostic ability.


CONCLUSIONS
In conclusion, both MET-PET and FDG-PET were considered to be equally useful for the differential diagnosis of lung tumors. Furthermore, MET uptake in lung lesions was found to correlate significantly with FDG uptake.
Sasaki
M
M
Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan. msasaki@radiol.med.kyushu-u.ac.jp
Kuwabara
Y
Y
Yoshida
T
T
Nakagawa
M
M
Koga
H
H
Hayashi
K
K
Kaneko
K
K
Chen
T
T
Ichiya
Y
Y
Masuda
K
K
D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D005188:False Negative Reactions; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism*; D006801:Humans; D008171:Lung Diseases / Q000000981:diagnostic imaging; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D008715:Methionine / Q000378:metabolism*; D008875:Middle Aged; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D014055:Tomography, Emission-Computed
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D008715:Methionine