BACKGROUNDTo evaluate the diagnostic significance of FDG PET in preoperative mediastinal lymph node staging for NSCLC.

METHODSWhole-body FDG PET imaging was performed in 70 patients with NSCLC. All patients received thoracic CT examination 2 weeks before PET scan or 1 week after PET scan, and then were given thoracotomy with hilar and mediastinal lymph nodes dissection. After intravenous administration of 18F-FDG (150μCi/kg), PET scan was performed in 3-7 bed positions with 2D acquisition and OSEM reconstruction. For quantitative evaluation, a region of interest (ROI) was placed over the mediastinal lymph node which had abnormal uptake of radiation activity, then the standardized uptake value (SUV) were calculated. If SUV≥2.5 or uptake activity was higher than the blood pool of mediastinal on the basis of visual inspection, it was considered to be positive.

RESULTSThe sensitivity, specificity and accuracy of PET were 100%, 93% and 94%, respectively. The positive lymph nodes diagnosed by PET correctly corresponded to pathological results. PET changed the clinical staging of 12 patients. The sensitivity, specificity and accuracy of CT were 70%, 77% and 76%, respectively.

CONCLUSIONSPET is an effective modality for accurate mediastinal lymph node staging in patients with NSCLC. It is valuable for determining clinical treatment.