title: Regional nodal staging with 18F-FDG PET-CT in non-small cell lung cancer: Additional diagnostic value of CT attenuation and dual-time-point imaging.
abstract: BACKGROUND
  [Fluorine-18]-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET-CT) is widely performed in the regional nodal staging of non-small cell lung cancer (NSCLC). However, the uptake of (18)F-FDG by tubercular granulomatous tissues may lead to false-positive diagnosis. This is of special concern in China, where tubercular granulomatous disease is epidemic. Herein, we evaluated the efficacy of an additional CT attenuation and a dual-time-point scan in determining the status of lymph nodes.
  
  
  METHODS
  Eighty NSCLC patients underwent curative surgical resection after (18)F-FDG PET-CT and separate breath-hold CT examinations. The initial images were analyzed by two methods. In method 1, nodal status was determined by (18)F-FDG uptake only. In Method 2, nodal status was determined by (18)F-FDG uptake associated with CT attenuation. For dual-time-point imaging, the retention index (RI) of benign and malignant nodal groups with positive uptake in the initial scan was examined.
  
  
  RESULTS
  A total of 265 nodal groups were documented. On a per-nodal-group basis, the diagnostic sensitivity, specificity, and accuracy of Method 1 were 66.7%, 89.7%, and 85.3%, respectively, whereas those of Method 2 were 64.7%, 96.7%, and 90.6%, respectively. The improvement in diagnostic specificity and accuracy associated with the addition of CT attenuation in Method 2 as compared to Method 1 was statistically significant (p<0.01). Thirty-nine nodal groups with positive uptake in the initial scan underwent dual-time-point imaging and the difference in the RI between benign and malignant groups showed no statistical significance (p>0.05).
  
  
  CONCLUSIONS
  (18)F-FDG PET-CT has high diagnostic value for preoperative lymph-node (N) staging of NSCLC patients. We show that (18)F-FDG uptake combined with CT attenuation improves the diagnostic specificity and accuracy of nodal diagnosis in NSCLC. For the lymph nodes with positive uptake in the initial scan, dual-time-point imaging has limited effect in differentiation.
authors.affiliation: Department of Diagnostic Radiology, Cancer Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100021, China. caseylimeng@126.com
authors.forename: Meng
authors.initials: M
authors.lastname: Li
authors.forename: Ning
authors.initials: N
authors.lastname: Wu
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.forename: Rong
authors.initials: R
authors.lastname: Zheng
authors.forename: Ying
authors.initials: Y
authors.lastname: Liang
authors.forename: Wenjie
authors.initials: W
authors.lastname: Zhang
authors.forename: Ping
authors.initials: P
authors.lastname: Zhao
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008175:Lung Neoplasms / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18