Dual-time-point FDG PET/CT: Is It Useful for Lymph Node Staging in Patients with Non-Small-Cell Lung Cancer?

Purpose: Dual-time-point (DTP) FDG PET/CT has been shown to be useful for lymph node (LN) staging in patients with non-small-cell lung cancer (NSCLC). The aim of this study was to evaluate the LN staging ability of DTP FDG PET/CT in the predominant area of pulmonary tuberculosis. Methods: Sixty-nine NSCLC patients underwent DTP PET/CT. Regions of interest were placed on each LN of each station, and the maximum SUVs were measured. Three variables were obtained: (1) the SUV on the early scan (SUV early), (2) the SUV on the delayed scan (SUV delayed), and (3) the retention index of the SUV (RI). Each patient had one final LN stage and three other LN stages according to the cutoff values of SUV early, SUV delayed, and RI. Results: In the LN-based analysis, the area under the ROC curve of SUV delayed (0. 884) was significantly larger (P < 0. 01) than those of SUV early (0. 868) and RI (0. 717). Among the three variables, SUV delayed was more accurate (P < 0. 01) for detecting the mediastinal LN metastasis than SUV early and RI. In the patient-based analysis, SUV delayed had correctly determined LN stages in 55 of 69 patients (sensitivity, specificity, and accuracy = 88. 7 %, 50. 0 %, and 79. 7 %), whereas SUV early and RI correctly determined LN stages in 53 and 52 patients, respectively. Conclusions: In this study, comparing the diagnostic efficacy of SUV early, SUV delayed, and RI for LN staging in patients with NSCLC, SUV delayed was the most accurate variable for LN staging. DTP PET/CT could provide improved diagnostic accuracy for the LN staging of NSCLC. © 2012 Korean Society of Nuclear Medicine.