title: 18F-FDG PET for the lymph node staging of non-small cell lung cancer in a tuberculosis-endemic country: is dual time point imaging worth the effort?
abstract: OBJECTIVE
  This study was to compare (18)F-FDG positron emission tomography (PET) with thoracic contrast-enhanced CT (CECT) in the ability of lymph node (LN) staging non-small cell lung cancer (NSCLC) in a tuberculosis-prevalent country. The usefulness of dual time point PET imaging (DTPI) in NSCLC nodal staging was also evaluated.
  
  
  METHODS
  We reviewed 96 NSCLC patients (mean age, 65.3+/-11.7 years) who had received PET studies before their surgery. DTPI were performed on 37 patients (mean age, 64.8+/-12.2 years) who received an additional scan of thorax 3 h after tracer injection. The accuracies of nodal staging by CECT and PET were evaluated according to final histopathology of hilar and mediastinal LN resected by surgery.
  
  
  RESULTS
  The accuracy for nodal staging by CECT was 65.6% and that by PET was 82.3% (p<0.05). Six patients were over-staged and 11 were under-staged by PET. Tuberculosis (n=3, 50%) were mostly responsible for false-positive, while small tumor foci (n=7, 63.6%) were mostly accountable for false-negative. For the 37 patients with DTPI, 45 min standardized uptake value (SUV) and 3 h SUV for negative LNs are significantly lower than those for positive LNs (p<0.0001). Nevertheless, the retention index (RI) showed no significant difference between these two groups.
  
  
  CONCLUSIONS
  Our study demonstrates that PET is more accurate than CECT in LN staging NSCLC patients in Taiwan where TB is still prevalent. Semi-quantitative SUV method or DTPI with RI does not result in better diagnostic accuracy than visual analysis of PET images.
authors.affiliation: Department of Nuclear Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Ruoh-Fang
authors.initials: RF
authors.lastname: Yen
authors.forename: Ke-Cheng
authors.initials: KC
authors.lastname: Chen
authors.forename: Jang-Ming
authors.initials: JM
authors.lastname: Lee
authors.forename: Yeun-Chung
authors.initials: YC
authors.lastname: Chang
authors.forename: Jane
authors.initials: J
authors.lastname: Wang
authors.forename: Mei-Fang
authors.initials: MF
authors.lastname: Cheng
authors.forename: Yen-Wen
authors.initials: YW
authors.lastname: Wu
authors.forename: Yung-Chie
authors.initials: YC
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000150:complications / Q000000981:diagnostic imaging* / Q000556:secondary*; D005189:False Positive Reactions; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000150:complications / Q000000981:diagnostic imaging*; D008207:Lymphatic Metastasis / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D013624:Taiwan; D014057:Tomography, X-Ray Computed; D014397:Tuberculosis, Pulmonary / Q000150:complications
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18