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

Abstract

UNLABELLED: Our purpose was to compare the performance of (68)Ga-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 (18)F-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 (68)Ga-DOTATATE and (18)F-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 (68)Ga-DOTATATE (maximum standardized uptake value [SUV(max)] >or= 8.2), but 4 of 11 showed negative or minimal (18)F-FDG uptake (SUV(max) = 1.7-2.9). All tumors of higher grade showed high uptake of (18)F-FDG (SUV(max) >or= 11.7), but 3 of 5 showed only minimal accumulation of (68)Ga-DOTATATE (SUV(max) = 2.2-2.8). Neither case of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia showed uptake of (68)Ga-DOTATATE or (18)F-FDG. Typical carcinoids showed significantly higher uptake of (68)Ga-DOTATATE and significantly less uptake of (18)F-FDG than did tumors of higher grade (P = 0.002 and 0.005). There was no instance of false-positive uptake of (68)Ga-DOTATATE, but there were 3 sites of (18)F-FDG uptake secondary to inflammation. (68)Ga-DOTATATE was superior to (18)F-FDG in discriminating endobronchial tumor from distal collapsed lung (P = 0.02). CONCLUSION: Typical bronchial carcinoids showed higher and more selective uptake of (68)Ga-DOTATATE than of (18)F-FDG. Atypical carcinoids and higher grades had less (68)Ga-DOTATATE avidity but were (18)F-FDG-avid.