Assessment of malignancy in pulmonary lesions: FDG dual-head coincidence gamma camera imaging in association with serum tumor marker measurement

The purpose of the study was to evaluate the performance of dual-head coinc idence gamma camera imaging using FDG in association with serum marker assa ys in identifying lung carcinoma in patients with abnormal findings on ches t radiography. Methods: A prospective evaluation of FDG imaging with coinci dence detection emission tomography (CDET) using a dual-head gamma camera c ombined with the assessment of 3 sensitive serum markers of lung cancer (ca rcinoembryonic antigen, neuron specific enolase, and CYFRA 21-1) was perfor med on the same day on 58 consecutive patients with known or suspected lung malignancy. Results: Fifty-three patients were proven to have lung cancer, and 5 patients had benign lung disease. Coincidence imaging showed signifi cantly increased FDG uptake in 49 of 53 patients with proven malignancy (se nsitivity, 92.5%) and in 3 patients with benign disease. FDG imaging had ne gative findings in 4 patients with proven malignancy and 2 patients with be nign disease. Serum tumor marker levels were elevated in 42 of 53 cancer pa tients (sensitivity, 79.2%) and normal in 11 patients with proven malignanc y. Nine patients with proven malignancy had positive findings on FDG images and negative marker assays. Two patients with proven malignancy had negati ve findings on FDG images and positive marker assays. The positive predicti ve value for lung cancer was 94.2% for FDG alone and 97.6% for FDG in assoc iation with serum markers. Conclusion: In this study, FDG CDET imaging was a powerful tool for evaluating patients with lung lesions suggestive of mal ignancy. Although the determination of serum marker levels was less accurat e than FDG imaging, positive FDG results found in association with positive markers significantly increased the likelihood of lung malignancy.