Comparison of 11C-methionine PET and 18F-FDG PET in patients with primary central nervous system lymphoma.
OBJECTIVE
2-deoxy-2-[(18)F]fluoro-D-glucose (FDG) positron emission tomography (PET) has been used as a promising tool to diagnose primary central nervous system (CNS) lymphoma because the tumor shows very high FDG accumulation. Although (11)C-methionine (MET) PET has been reported to be useful for evaluating various brain tumors, the role of MET PET in CNS lymphoma is unclear. We compared the uptake of MET and FDG in patients with CNS lymphoma.


METHODS
Thirteen immunocompetent patients with CNS lymphoma were examined. All patients underwent PET with MET (15 min p.i.) and FDG (60 min p.i.). PET results were evaluated by visual and semi-quantitative analysis. For semi-quantitative analysis, the standardized uptake value (SUV) and tumor to contralateral normal brain tissue (T/N) ratio were determined by region-of-interest analysis.


RESULTS
For detection of CNS lymphoma, sensitivity of PET using both MET and FDG was 100%. The mean (±SD) value of SUV in the contralateral normal brain tissue using MET (1.43 ± 0.21) was significantly lower than that using FDG (5.58 ± 1.79; p < 0.002). The mean (±SD) value of SUV in the CNS lymphoma using MET (4.27 ± 1.91) was significantly lower than that of FDG (13.94 ± 5.65; p < 0.002). There were no significant differences between mean (±SD) T/N ratios using MET PET (3.00 ± 1.26) and FDG PET (2.74 ± 1.25).


CONCLUSIONS
There was no significant difference between T/N ratios using MET PET and FDG PET, although uptake of MET in CNS lymphoma was significantly lower than that of FDG. MET PET showed as high a sensitivity as FDG PET for the detection of primary lesions in patients with CNS lymphoma.
Department of Radiology, Faculty of Medicine, Kagawa University, Kita-gun, Kagawa, Japan. kawase@kms.ac.jp
Yoshiro
Y
Kawase
Yuka
Y
Yamamoto
Reiko
R
Kameyama
Nobuyuki
N
Kawai
Nobuyuki
N
Kudomi
Yoshihiro
Y
Nishiyama
D000368:Aged; D000369:Aged, 80 and over; D002250:Carbon Radioisotopes; D016543:Central Nervous System Neoplasms / Q000000981:diagnostic imaging*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D016014:Linear Models; D008223:Lymphoma / Q000000981:diagnostic imaging*; D008297:Male; D008715:Methionine; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011859:Radiography
D002250:Carbon Radioisotopes; D019788:Fluorodeoxyglucose F18; D008715:Methionine