OBJECTIVETo evaluate the clinical value of (18)F-FDG PET-CT and enhanced CT imaging for staging of regional lymph node metastasis in non-small cell lung cancer (NSCLC) patients.

METHODS122 patients with proven or suspected NSCLC underwent integrated PET-CT and enhanced CT scan before surgery. The results of lymph node metastasis diagnosed by PET-CT and CT were compared and analyzed according to the results of histopathological examination.

RESULTSPET-CT showed correctly lymph node staging in 80.3% of cases, overstaged in 13.1%, and understaged in 6.6%, while 55.8%, 26.2% and 18.0% by CT, respectively. The sensitivity, specificity, and accuracy of PET-CT for lymph node staging was 86.3%, 85.0% and 85.3%, respectively, while the corresponding data were 68.6%, 71.0% and 70.4% by CT, respectively (P < 0.01). 81.3% of false-negative and 71.6% false-positive lymph nodes by CT were interpreted correctly by PET-CT, while 57.1% of false-negative and 45.2% of false-positive lymph nodes by PET-CT were correctly diagnosed by CT. 5.9% of PET-CT-diagnosed negative lymph nodes were pathologically proven to be positive with small cancer foci and below 10 mm in diameter, while 8.2% of pathologically proven negative lymph nodes with inflammation, high FDG uptake and exceeding 10 mm (15 mm in subcarnial nodes) in diameter were false-positive on both PET-CT and CT imaging, therefore, these lymph nodes were still in the common blind area of diagnosis by both of PET-CT and CT.

CONCLUSIONCompared with enhanced CT, integrated PET-CT improves the accuracy and is helpful to correct some CT-diagnosed false-positive and false-negative lymph nodes. But CT is also beneficial supplementation to PET-CT for assessment of regional lymph node metastasis. The combination of PET-CT and CT can make up the shortage of both of them in staging of regional lymph nodes in NSCLC patients.