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

Abstract

Our purpose was to compare the performance of 68 4,7,N9,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 ] $ 8.2), but 4 of 11 showed negative or minimal 18 F-FDG uptake (SUV max 5 1.7-2.9). All tumors of higher grade showed high uptake of 18 F-FDG (SUV max $ 11.7), but 3 of 5 showed only minimal accumulation of 68 Ga-DOTATATE (SUV max 5 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 5 0.002 and 0.005). There was no instance of falsepositive 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 5 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.

Ectopic ACTH Syndrome Caused by Multifocal Pulmonary Carsinoids with 18f-FDG Uptake: Case Report

“…Some papers report limited value of 18-FDG PET CT in detecting neuroendocrine tumours, due to low proliferative activity of these tumours. 11,12 However this examination was positive in our case, in accordance with the findings of Daniels et al who demonstrated a trend toward higher PET sensitivity for atypical carcinoid tumors in their cohort. 13 A multidisciplinary approach is required in order to diagnose and localise ACTH oversecretion.…”

Diagnostic Performance of 68Ga-DOTATATE PET/CT, 18F-FDG PET/CT and 131I-MIBG Scintigraphy in Mapping Metastatic Pheochromocytoma and Paraganglioma

“…Studies have demonstrated that de-differentiated neuroendocrine tumours (NET) exhibit high GLUT-1 glucose transporter expression with low expression of somatostatin receptor [35,36]. This gives the notion that somatostatin receptor expression lesions are generally associated with differentiated tumours, and as these tumours transform to more aggressive behaviour, there is shift from 68 Ga-DOTA-peptide uptake to 18 F-FDG uptake-the so called 'flip-flop' phenomenon.…”

Evolving role of PET/CT with different tracers in the evaluation of pulmonary neuroendocrine tumours

“…These authors demonstrated that typical BCs showed significantly higher uptake of 68 Ga-somatostatin analogues and significantly lower uptake of 18 F-FDG compared to pulmonary NETs of higher grade. No false-positive uptake of 68 Ga-DOTATATE was reported in this study population, but there were three sites of false-positive uptake of 18 F-FDG due to inflammation [12]. Jindal et al retrospectively evaluated the role of 68 Ga-DOTATOC and 18 F-FDG PET/CT in differentiating typical and atypical BCs.…”

“…Furthermore, 68 Ga-somatostatin analogues provided better results compared to the radiolabelled amino acid 18 Fdihydroxyphenylalanine (DOPA) in evaluating lung NETs [6], but literature reports specifically addressing the use of 18 F-DOPA in pulmonary NETs are few [11]. Since different information may be obtained using various PET tracers, some authors have recently reported preliminary results on dual-tracer PET/CT imaging using 68 Ga-somatostatin analogues and 18 F-FDG in well-differentiated pulmonary NETs [12][13][14][15]. A retrospective study by Kayani et al compared 68 Ga-DOTATATE and 18 F-FDG PET/CT findings in 18 patients with pulmonary NETs, including 13 BCs.…”