Functional imaging in differentiating bronchial masses: an initial experience with a combination of 18F-FDG PET-CT scan and 68Ga DOTA-TOC PET-CT scan

Objective To evaluate the role of combination of F-18-FDG PET-CT scan and Ga-68 DOTA-TOC PET-CT scan in differentiating bronchial tumors observed in contrast enhanced computed tomography scan of chest. Study design: Prospective observational study. Place of study: All India Institute of Medical Sciences, New Delhi, India. Methods 7 patients with bronchial mass detected in computed tomography scan of the chest were included in this study. All patients underwent F-18-FDG PET-CT scan, Ga-68 DOTA-TOC PET-CT scan and fiberoptic bronchoscope guided biopsy followed by definitive surgical excision. The results of functional imaging studies were analyzed and the results are correlated with the final histopathology of the tumor. Results Histopathological examination of 7 bronchial masses revealed carcinoid tumors (2 typical, 1 atypical), inflammatory myofibroblastic tumor (1), mucoepidermoid carcinoma (1), hamartoma (1), and synovial cell sarcoma (1). The typical carcinoids had mild F-18-FDG uptake and high Ga-68 DOTA-TOC uptake. Atypical carcinoid had moderate uptake of F-18-FDG and high Ga-68 DOTA-TOC uptake. Inflammatory myofibroblastic tumor showed high uptake of F-18-FDG and no uptake of Ga-68 DOTA-TOC. Mucoepidermoid carcinoma showed mild F-18-FDG uptake and no Ga-68 DOTA-TOC uptake. Hamartoma showed no uptake on either scans. Synovial cell sarcoma showed moderate F-18-FDG uptake and mild focal Ga-68 DOTA-TOC uptake. Conclusion This initial experience with the combined use of F-18-FDG and Ga-68 DOTA-TOC PET-CT scan reveals different uptake patterns in various bronchial tumors. Bronchoscopic biopsy will continue to be the gold standard; however, the interesting observations made in this study merits further evaluation of the utility of the combination of F-18-FDG PET-CT scan and Ga-68 DOTA-TOC PET-CT scan in larger number of patients with bronchial masses.