TY - JOUR T1 - <sup>68</sup>Ga-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 DO - 10.2967/jnumed.116.179192 SP - jnumed.116.179192 AU - Wolfgang Peter Fendler AU - Martin Barrio AU - Claudio Spick AU - Martin Allen-Auerbach AU - Valentina Ambrosini AU - Matthias Benz AU - Christina Bluemel AU - Ravinder Grewal AU - Constantin Lapa AU - Matthias Miederer AU - Guillaume Nicolas AU - Tibor Schuster AU - Johannes Czernin AU - Ken Herrmann Y1 - 2016/08/01 UR - http://jnm.snmjournals.org/content/early/2016/08/17/jnumed.116.179192.abstract N2 - 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 (&lt;500 scans or &lt;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. ER -