||<Original article> Usefulness of delayed scan of FDG PET for the diagnosis of lymph node metastasis in non-small cell lung cancer
8 , 2016 , 山梨大学医学会
PURPOSE: The purpose of this study was to evaluate the usefulness of delayed scan of 18F fluorodeoxyglucose positron emission tomography (FDG-PET) for the diagnosis of lymph node (LN) metastasis in non-small cell lung cancer (NSCLC).METHODS: The subjects were 92 patients with NSCLC, who were examined dual-timepoint FDG-PET. A total of 510 LN stations were evaluated histologically. The maximum standardized uptake values (SUV) of LN stations were measured at early and delayed phases on FDG-PET study. We evaluated the diagnostic accuracy of LN metastasis when using the combined criteria of early SUV and retention index (RI) cut-off value in comparison with that using early SUV alone.RESULTS: The mean RIs of the LN stations with and without metastasis were 15.67 ± 19.07% and ?1.93 ± 14.66% (p<0.01). When the cut-off value of SUV at early scan as the criterion of malignancy was set at 2.5 and 2.0, the sensitivities, specifi cities, and accuracies were 39.3%, 94.3% and 88.2% (SUV>2.5), and 66.1%, 79.5% and 78.0% (SUV>2.0). If RI more than 10% was added into the criteria, the sensitivities, specifi cities, and accuracies became 32.1%, 98.2% and 91.0% (SUV>2.5), 53.6%, 96.5% and 91.8% (SUV>2.0).CONCLUSIONS: Metastatic LNs have a higher RI than non-metastatic ones. The combined criteria of early SUV and RI can improve the accuracy of the diagnosis of LN metastasis in NSCLC.