A Comparison of 68Ga-DOTATATE and 18F-FDG PET/CT in Pulmonary Neuroendocrine Tumors

Our purpose was to compare the performance of Ga-68-1,4,7, 10-tetraazacyclododecane-N,N',N '',N'''-tetraacetic acid-D-Phe(1), Tyr(3)-octreotate (DOTATATE), a novel selective somatostatin receptor 2 PET ligand, and F-18-FDG in the detection of pulmonary neuroendocrine tumors using PET/CT, with correlation of uptake and tumor grade on histology. Methods: The imaging findings of the first 18 consecutive patients (8 men and 10 women) with pulmonary neuroendocrine tumors (11 typical carcinoids, 2 atypical carcinoids, 1 large cell neuroendocrine tumor, 1 small cell neuroendocrine carcinoma, 1 non-small cell lung cancer with neuroendocrine differentiation, and 2 cases of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia) who underwent Ga-68-DOTATATE and F-18-FDG PET/CT were reviewed. In all cases, the diagnosis was established on histology. Results: Of 18 patients, 15 had primary tumors (median size, 2.7 cm; range, 0.5-8 cm) and 3 had recurrent tumors. All typical carcinoids showed high uptake of Ga-68-DOTATATE (maximum standardized uptake value [SUVmax] >= 8.2), but 4 of 11 showed negative or minimal F-18-FDG uptake (SUVmax = 1.7-2.9). All tumors of higher grade showed high uptake of F-18-FDG (SUVmax >= 11.7), but 3 of 5 showed only minimal accumulation of Ga-68-DOTATATE (SUVmax = 2.2-2.8). Neither case of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia showed uptake of Ga-68-DOTATATE or F-18-FDG. Typical carcinoids showed significantly higher uptake of Ga-68-DOTATATE and significantly less uptake of F-18-FDG than did tumors of higher grade (P = 0.002 and 0.005). There was no instance of false-positive uptake of Ga-68-DOTATATE, but there were 3 sites of F-18-FDG uptake secondary to inflammation. Ga-68-DOTATATE was superior to F-18-FDG in discriminating endobronchial tumor from distal collapsed lung (P = 0.02). Conclusion: Typical bronchial carcinoids showed higher and more selective uptake of Ga-68-DOTATATE than of F-18-FDG. Atypical carcinoids and higher grades had less Ga-68-DOTATATE avidity but were F-18-FDG-avid.