RT Journal Article SR Electronic T1 68Ga-DOTATATE PET/CT interobserver agreement for neuroendocrine tumor assessments: results from a prospective study on 50 patients JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP jnumed.116.179192 DO 10.2967/jnumed.116.179192 A1 Wolfgang Peter Fendler A1 Martin Barrio A1 Claudio Spick A1 Martin Allen-Auerbach A1 Valentina Ambrosini A1 Matthias Benz A1 Christina Bluemel A1 Ravinder Grewal A1 Constantin Lapa A1 Matthias Miederer A1 Guillaume Nicolas A1 Tibor Schuster A1 Johannes Czernin A1 Ken Herrmann YR 2016 UL http://jnm.snmjournals.org/content/early/2016/08/17/jnumed.116.179192.abstract AB We evaluated the observer agreement for 68Ga-DOTATATE PET/CT study interpretations in patients with neuroendocrine tumors (NET). Methods: 68Ga-DOTATATE PET/CT was performed in 50 patients with known or suspected NET of the small bowel (n = 19), pancreas (n = 14), lung (n = 4) or other location (n = 13). Images were reviewed by seven observers who used a standardized approach for image interpretation. Observers were classified as having low (<500 scans or <5 years experience with 68Ga-DOTATATE PET/CT; n = 4) or high level of experience (≥500 scans and ≥5 years experience with 68Ga-DOTATATE PET/CT; n = 3). Interpretation by the primary nuclear medicine physician un-blinded to all clinical and imaging data served as reference standard. Interobserver agreement was determined by Cohen's κ and intraclass correlation coefficient (ICC) with corresponding 95% confidence interval (CI). Results: Interobserver agreement was substantial and the median number of false findings (FF) was low for the overall scan result; i.e. positive versus negative study (κ = 0.80, 95%CI 0.74-0.86; FF = 3), organ involvement (κ = 0.70, 95%CI 0.64-0.76; FF = 5), and lymph node involvement (κ = 0.71, 95%CI 0.65-0.78; FF = 6). The interobserver agreement was substantial to almost-perfect and the average absolute difference (Δ) to the reference reader was low for number of organ and lymph node metastases (ICC = 0.84, 95%CI 0.77-0.89, Δ = 0.45 and ICC = 0.77, 95%CI 0.69-0.84, Δ = 0.45), tumor SUVmax (ICC = 0.99, 95%CI 0.97-0.99; Δ = 0.44) and reference SUV (SUVmean spleen: ICC = 0.81, Δ = 1.10; SUVmax liver ICC = 0.79, Δ = 0.62). Interpretations of the appropriateness for peptide-receptor radionuclide therapy (PRRT) varied more significantly among observers (κ = 0.64, 95%CI 0.57-0.70) and a higher frequency of false positive recommendations for PRRT occurred in observers with low versus high levels of experience (range, 7-12 versus 4-8). Conclusion: The interpretation of 68Ga-DOTATATE PET/CT for NET staging is consistent among readers with low and high levels of experience. However, image based recommendations for or against PRRT require experience and training.