Use of a dual-head coincidence camera and 18F-FDG for detection and nodal staging of non-small cell lung cancer: accuracy as determined by 2 independent observers.

UNLABELLED: The accurate detection of lung carcinoma and the determination of its stage remain significant clinical problems. (18)F-FDG PET has been shown to improve detection and staging of lung cancer and to prevent unnecessary invasive procedures. Positron imaging with dual-head gamma cameras may not be as sensitive as PET, but recent studies have shown good results with these cameras.

METHODS: In the present study, we investigated 100 patients, 76 of whom were male and 24 female (mean age +/- SD, 60.7 +/- 9.4 y), with suspected non-small cell lung cancer. (18)F-FDG scanning was performed using a dual-head coincidence camera 1 h after the intravenous injection of 185 MBq of (18)F-FDG. For 46 patients, attenuation correction was also performed. Two independent observers unaware of clinical status analyzed all imaging studies. TNM classification was assigned after surgical staging.

RESULTS: In 44 patients with clinically suspected bronchogenic carcinoma, no evidence of malignancy was found. However, in 56 patients a pulmonary neoplasm was demonstrated. At interobserver analysis, a kappa value of 0.94 (P < 0.0001) was found for detection of the primary tumor and a kappa value of 0.63 (P < 0.0001) was found for mediastinal staging. A sensitivity of 96%, a specificity of 93%, and an accuracy of 95% were found for detection of pulmonary neoplasm. Assessment of lymph node involvement showed a sensitivity of 50%, a specificity of 92%, and an accuracy of 77%. The sensitivity of CT in assessing lymph node involvement was 36%, the specificity was 86%, and the accuracy was 67%. Attenuation correction provided more anatomic information, but no differences were seen between attenuation-corrected and non-attenuation-corrected images for detecting lesions or lymph node involvement.

CONCLUSION: The present study confirms earlier data showing that (18)F-FDG scans obtained with dual-head coincidence cameras are useful in the detection of non-small cell lung cancer and less suitable for staging of lymph node involvement, with accuracy comparable to that of CT.