FLUORINE-18-FDG PET IMAGING IS NEGATIVE IN BRONCHIOLOALVEOLAR LUNG-CARCINOMA

The goals of our study were to establish PET accuracy with F-18- fluor odeoxyglucose (FDG) in finding localized formations of bronchioloalveo lar lung carcinoma (BAC) and to investigate the correlation between FD G uptake and the degree of cell differentiation in adenocarcinoma of t he lung. Materials: Twenty-nine patients with 30 adenocarcinomas of th e lung (7 bronchioloalveolar lung carcinomas, 9 well differentiated, 2 well-moderately differentiated, 11 moderately differentiated and 1 po orly differentiated) were studied. All patients underwent thoracotomie s within 4 wk after the FDG PET study. For qualitative analysis, the d egree of FDG activity in the tumors was visually scored using a five-p oint grading system: 0 = same to background activity, 1 = less than me diastinal blood-pool activity, 2 = same to mediastinal blood-pool acti vity, 3 = slightly greater than mediastinal blood-pool activity and 4 = substantially greater than mediastinal blood-pool activity. Foci of activity with Grades 2-4 were considered tumors. For semiquantitative analysis, standardized uptake values (SUV) were calculated. Results: I n 7 BACs, 4 lesions (57%) showed negative results on FDG PET, while in 23 non-BACs, only 1 lesion (4%), which was a well-differentiated aden ocarcinoma showed a negative result. BACs' mean visual score (1.43 +/- 1.27) was significantly lower than that of non-BACs (3.17 +/- 1.03) ( p = 0.001). The BACs' mean SUV (1.36 +/- 0.821) was significantly lowe r than that of well-differentiated adenocarcinomas (2.92 +/- 1.28) (p = 0.014); the mean SUV of well-differentiated adenocarcinomas was sign ificantly lower than that of moderately differentiated adenocarcinomas (4.63 +/- 1.86) (p = 0.031). No significant differences were apparent in average size among these three histologic types. Conclusion: A cor relation was observed between FDG uptake and the degree of cell differ entiation in adenocarcinoma of the lung. FDG PET may show negative res ults for BAC.