Predicting malignancy grade with PET in non-Hodgkin's lymphoma.
Our goal was to determine whether PET with 11C-methionine and/or 18FDG could predict malignancy grade in non-Hodgkin's lymphoma (NHL).


METHODS
Twenty-three patients with high-grade, low-grade or transformed low-grade NHL were investigated. Standardized uptake values (SUV), transport rate and mass influx values were calculated both for the whole tumor [mean regions of interest, (ROI)] and for the tumor area with the highest levels of activity, comprising four contiguous pixels within each tumor and designated as a hot spot.


RESULTS
Both 11C-methionine and 18FDG detected all tumors. In addition, 18FDG discriminated between high- and low-grade NHL, whereas 11C-methionine did not. With 18FDG, three transformed low-grade NHLs behaved in an intermediate manner. All quantitative uptake values correlated well with each other for both tracers, except for the mean ROI SUV and transport rate of 11C-methionine. Quantifications of mean ROI uptake and hot spots were strongly correlated.


CONCLUSIONS
The results of this study together with previous findings from other studies indicate that 18FDG but not 11C-methionine can predict malignancy grade in NHL. Further studies with a larger series of patients are needed.
Rodriguez
M
M
Department of Diagnostic Radiology, University of Uppsala, Akademiska Sjukhuset, Sweden.
Rehn
S
S
Ahlström
H
H
Sundström
C
C
Glimelius
B
B
D000328:Adult; D000368:Aged; D003847:Deoxyglucose / Q000031:analogs & derivatives*; D005260:Female; D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008228:Lymphoma, Non-Hodgkin / Q000000981:diagnostic imaging* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008715:Methionine; D008875:Middle Aged; D011237:Predictive Value of Tests; D014055:Tomography, Emission-Computed
D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; C086242:carbon-11 methionine; D003847:Deoxyglucose; D008715:Methionine