Author/Authors :
Fallahi ، Babak - Tehran University of Medical Sciences , Manafi-Farid ، Reyhaneh - Tehran University of Medical Sciences , Eftekhari ، Mohammad - Tehran University of Medical Sciences , Fard-Esfehani ، Armaghan - Tehran University of Medical Sciences , Emami-Ardekani ، Alireza - Tehran University of Medical Sciences , Geramifar ، Parham - Tehran University of Medical Sciences , Akhlaghi ، Mehdi - Tehran University of Medical Sciences , Hashemi Taheri ، Amir Pejman - Tehran University of Medical Sciences , Beiki ، Davood - Tehran University of Medical Sciences
Abstract :
Objective(s): In view of somatostatin receptor (SSR) expression on cell membranes of the majority of neuroendocrine tumors (NETs), functional imaging exploiting analogs of SSR alongside the anatomical imaging is the mainstay of this diagnostic modality. In this prospective study, we assessed and directly compared the diagnostic parameters of 68GaDOTATATE PET/CT and 99mTcOctreotide SPECT/CT, as well as CT/MRI. Methods: Twentyfive NET patients, either histologically proven or highly suspicious for NET, who were referred for Octreotide Scan were enrolled in this prospective study. They all underwent 99mTcOctreotide SPECT/CT and then 68GaDOTATATE PET/CT. A blind interpretation was conducted for each imaging as well as for the previously obtained conventional imaging (CT or MRI). The patientbased and lesionbased analysis were conducted and the results of the three modalities were compared. The histopathologic confirmation or followup data were considered as the gold standard. Also, the impact of 68GaDOTATATE PET/CT on the patient’s management was assessed. Results: Overall, 77 lesions in 14 patients, 135 in 19 and 86 in 16 were detected on 99mTcOctreotide SPECT/CT, 68GaDOTATATE PET/CT and CT/MRI, respectively. On patientbased analysis, the sensitivity was 65%, 90% and 71% for 99mTcOctreotide SPECT/CT, 68GaDOTATATE PET/CT and CT/MRI, respectively. Also, the specificity was 80%, 80% and 75% for 99mTcOctreotide SPECT/CT, 68GaDOTATATE PET/CT and CT/MRI, respectively. The correlation between 68GaDOTATATE PET/CT and 99mTcOctreotide SPECT/CT results was significant (P=0.02; kappa value=0.57), no correlation, however, was depicted with CI (P=0.07; kappa value=0.35). On lesionbased analysis, 68GaDOTATATE PET/CT found more organs (P=0.02) and lesions (P=0.001) in comparison with 99mTcOctreotide SPECT/CT and also more lesions in comparison with CT/MRI (P=0.003). In addition, comparing with 99mTcOctreotide SPECT/CT and CT/MRI, 68GaDOTATATE PET/CT revealed more data in 44% and 36% of the patients, resulting in management modification in 24% and 20%, respectively. Conclusion: Comparing with 99mTcOctreotide SPECT/CT and CT/MRI, 68Ga DOTATATE PET/CT provided more sensitivity and specificity in patients with NETs showing more involved organs as well as tumoral lesions. Also, 68GaDOTATATE PET/ CT led to change of management in up to onefourth of the patients, especially in a subgroup reevaluated for recurrence.
