Differentiation of newly diagnosed glioblastoma multiforme and intracranial diffuse large B-cell Lymphoma using (11)C-methionine and (18)F-FDG PET.
OBJECTIVE
The aim of our study was to examine the usefulness of PET with C-methionine (MET) and F-fluorodeoxyglucose (FDG) in the differentiation of glioblastoma multiforme (GBM) and intracranial diffuse large B-cell lymphoma (DLBCL).


METHODS
We evaluated 22 patients retrospectively with an enhancing brain tumor on MRI, including 15 GBM and 7 DLBCL, which was confirmed by histopathology. Dynamic PET scans with MET and FDG were performed for preoperative differential diagnosis. We assessed the images qualitatively and quantitatively. In quantitative assessment, the SUVmax was used on FDG PET and both late and early phases on MET PET. In addition, the ratio of SUVmax in the late and early phases on MET-PET was evaluated (ΔSUVmax).


RESULTS
SUVmax on FDG PET of DLBCL was significantly higher than that of GBM. Setting an SUVmax of 12.0 as the cutoff for differentiating DLBCL from GBM, 1 GBM and 1 DLBCL were found to be false-positive and false-negative, respectively.SUVmax in the late and early phases of MET-PET was not significantly different between DLBCL and GBM; however, we also found significant differences in ΔSUVmax on MET-PET. Using ΔSUVmax 1.17 as the cutoff, we could differentiate DLBCL from GBM completely. In the present study, ΔSUVmax on MET-PET was slightly superior to SUVmax on FDG PET.


CONCLUSIONS
Both SUVmax on FDG PET and ΔSUVmax on MET-PET were considered to be good diagnostic tests when encountering difficulties in this differential diagnosis.
Department of Radiology, Nagoya University Graduate School of Medicine, 65 Tsurumai cho, Shouwa ku, Nagoya, 466-8550, Japan. yumi_oka1004@yahoo.co.jp
Yumiko
Y
Okada
Takashi
T
Nihashi
Masazumi
M
Fujii
Katsuhiko
K
Kato
Yoshiyuki
Y
Okochi
Yoshio
Y
Ando
Masato
M
Yamashita
Satoshi
S
Maesawa
Shigenori
S
Takebayashi
Toshihiko
T
Wakabayashi
Shinji
S
Naganawa
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D005260:Female; D019788:Fluorodeoxyglucose F18; D005909:Glioblastoma / Q000000981:diagnostic imaging*; D006801:Humans; D016403:Lymphoma, Large B-Cell, Diffuse / Q000000981:diagnostic imaging*; D008297:Male; D008715:Methionine; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011786:Quality Control; D012189:Retrospective Studies; D055815:Young Adult
D019788:Fluorodeoxyglucose F18; C086242:carbon-11 methionine; D008715:Methionine