Hybrid SPECT/CT Somatostatin Receptor Imaging of Neuroendocrine Tumours

Cilj: Cilj rada bio je procijeniti doprinos jednofotonske emisijske tomografije / kompjutorizirane tomografije somatostatinskih receptora (SR SPECT/CT) s 99mTc-EDDA/HYNIC-Tyr3-oktreotidom (99mTc-Tektrotyd) u dijagnostici i procjeni proširenosti bolesti kod pacijenata oboljelih od neuroendokrinih tumora (NET-ova). Ispitanici i metode: Retrospektivno je analizirano 120 SR SPECT/CT snimanja pacijenata s patohistološki dokazanim NET-om s obzirom na vizualizaciju primarnih lezija i metastaza. U 45 pacijenata učinjena je i pozitronska emisijska tomografija 18F-fluorodeoksiglukozom (18F-FDG PET/CT) te su nalazi uspoređeni s nalazima SR SPECT/CT-a i vrijednostima kromogranina A. Rezultati: Od 120 pacijenata 47 (39 %) je na SR SPECT/CT upućeno nakon odstranjenja primarne lezije. Od preostala 73 pacijenta (61 %), u 56 (77 %) primarni je tumor bio vidljiv SR SPECT/CT-om, a u 9 (12 %) poznata lezija nije akumulirala radiofarmak. U 8 (11 %) pacijenata s NET-om nepoznatog primarnog sijela nalaz je bio negativan. Od 68 (57 %) pacijenta s dokazanim metastazama, u njih 57 (84 %) bile su vidljive SR SPECT/CT-om, a u 11 (16 %) nisu akumulirale radiofarmak. Od 45 (38 %) pacijenata kojima je učinjen i 18F-FDG PET/CT, u 27 (60 %) detekcija primarnih lezija i metastaza bila je sukladna nalazu SR SPECT/CT-a. Osjetljivost SR SPECT/CT-a bila je 77 % za primarne lezije i 84 % za metastaze, a 18F-FDG PET/CT-a 75 % za primarne lezije i 76 % za metastaze. Vrijednosti kromogranina A nisu pokazale statistički signifikantnu korelaciju s nalazima slikovne dijagnostike. Zaključci: SR SPECT/CT ima visoku osjetljivost za detekciju NET-ova. Osim toga, potvrđena je komplementarnost s 18F-FDG PET/CT-om te kod pacijenata s negativnim nalazom SR SPECT/CT-a treba učiniti 18F-FDG PET/CT i obrnuto.The aim: The aim of this study was to evaluate the significance of somatostatin receptor single-photon emission computed tomography/computed tomography (SR SPECT/CT) with 99mTc-EDDA/HYNIC-Tyr3-octreotide (99mTc-Tektrotyd) in diagnostics and staging of patients with neuroendocrine tumours. Patients and methods: We retrospectively enrolled 120 patients with histologically proven NET who underwent SR SPECT/CT between January 2013 and February 2017. The patients’ data and SR SPECT/CT findings regarding primary lesion and metastases were analysed. In 45 patients, 2-deoxy-2-18F-fluoroglucose positron emission computed tomography/computed tomography (18F-FDG PET/CT) was performed, and the findings were compared to SR SPECT/CT and chromogranin A values. Results: Out of 120 patients, 47 (39%) underwent SR SPECT/CT after surgical removal of the primary lesion. In 73 (61%) remaining patients, the primary lesion was detected on SR SPECT/CT in 56 (77%), in 9 (12%) lesion did not accumulate 99mTc-Tektrotyd. SR SPECT/CT was negative in the remaining 8 (11%) patients with unknown primary. Out of 68 patients (57%) with metastases, 57 (84%) were detected on SR SPECT/CT, while 11 did not accumulate 99mTc- Tektrotyd. 18F-FDG PET/CT was performed in 45 patients, and findings were concordant with SR SPECT/CT in 27 (60%). The the sensitivity of SR SPECT/CT was 77% for primary lesions and 84% for metastases, and sensitivity of 18F-FDG PET/CT was 75% 76%, respectively. In 70 (58%) patients with available chromogranin A no statistically significant correlation was found with imaging methods. Conclusion: In patients with NET and negative SR SPECT/CT findings, 18F-FDG PET/CT should be recommended and vice versa, because of the complementarity of these procedures