title: 68Ga-DOTATATE PET/CT Interobserver Agreement for Neuroendocrine Tumor Assessment: Results of a Prospective Study on 50 Patients.
abstract: We evaluated observer agreement for68Ga-DOTATATE PET/CT interpretations in patients with neuroendocrine tumor (NET).
  
  
  
  68Ga-DOTATATE PET/CT was performed on 50 patients with known or suspected NET of the small bowel (n = 19), pancreas (n = 14), lung (n = 4), or other location (n = 13). The images were reviewed by 7 observers, who used a standardized interpretation approach. The observers were classified as having a low level of experience (<500 scans or <5 y experience with68Ga-DOTATATE PET/CT; n = 4) or a high level of experience (≥500 scans or ≥5 y experience with68Ga-DOTATATE PET/CT; n = 3). Interpretation by the primary nuclear medicine physician, who had access to all clinical and imaging data, served as the reference standard. Interobserver agreement was determined by the Cohen κ statistic and intraclass correlation coefficient (ICC) with corresponding 95% confidence interval (95%CI).
  
  
  
  Interobserver agreement was substantial, and the median number of false findings was low for the overall scan result: that is, positive versus negative scan result (κ = 0.80; 95%CI, 0.74-0.86; false findings, 3), organ involvement (κ = 0.70; 95%CI, 0.64-0.76; false findings, 5), and lymph node involvement (κ = 0.71; 95%CI, 0.65-0.78; false findings, 6). Interobserver agreement was substantial to almost perfect, and the average absolute difference (Δ) from the reference observer was low for number of organ and lymph node metastases (organ: ICC, 0.84; 95%CI, 0.77-0.89; Δ = 0.45; lymph node: 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 (spleen: ICC, 0.81; Δ = 1.10; liver: ICC, 0.79; Δ = 0.62). Interpretations of appropriateness for peptide-receptor radionuclide therapy varied more significantly among observers (κ = 0.64; 95%CI, 0.57-0.70), and a higher frequency of false-positive recommendations for peptide-receptor radionuclide therapy occurred in observers with low experience than in those with high experience (range, 7-12 vs. 4-8).
  
  
  
  The interpretation of68Ga-DOTATATE PET/CT images for NET staging is consistent among observers with low and high levels of experience. However, image-based recommendations for or against peptide-receptor radionuclide therapy require experience and training.
authors.affiliation: Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, California.
authors.forename: Wolfgang Peter
authors.initials: WP
authors.lastname: Fendler
authors.affiliation: Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, California.
authors.forename: Martin
authors.initials: M
authors.lastname: Barrio
authors.affiliation: Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, California.
authors.forename: Claudio
authors.initials: C
authors.lastname: Spick
authors.affiliation: Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, California.
authors.forename: Martin
authors.initials: M
authors.lastname: Allen-Auerbach
authors.affiliation: Nuclear Medicine, Department of Experimental Diagnostic and Specialized Medicine, University of Bologna and S. Orsola-Malpighi Hospital, Bologna, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Ambrosini
authors.affiliation: Clinic of Radiology and Nuclear Medicine, University of Basel Hospital, Basel, Switzerland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Benz
authors.affiliation: Department of Nuclear Medicine, Julius-Maximilians-University, Würzburg, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Bluemel
authors.affiliation: Molecular Imaging and Therapy Service, Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, New York.
authors.forename: Ravinder Kaur
authors.initials: RK
authors.lastname: Grewal
authors.affiliation: Department of Nuclear Medicine, Julius-Maximilians-University, Würzburg, Germany.
authors.forename: Constantin
authors.initials: C
authors.lastname: Lapa
authors.affiliation: Department of Nuclear Medicine, University Medical Center Mainz, Mainz, Germany; and.
authors.forename: Matthias
authors.initials: M
authors.lastname: Miederer
authors.affiliation: Clinic of Radiology and Nuclear Medicine, University of Basel Hospital, Basel, Switzerland.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Nicolas
authors.affiliation: Department of Family Medicine, McGill University, Montreal, Quebec, Canada.
authors.forename: Tibor
authors.initials: T
authors.lastname: Schuster
authors.affiliation: Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, California.
authors.forename: Johannes
authors.initials: J
authors.lastname: Czernin
authors.affiliation: Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, California kherrmann@mednet.ucla.edu.
authors.forename: Ken
authors.initials: K
authors.lastname: Herrmann
mesh_terms: D000328:Adult; D000368:Aged; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008297:Male; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000000981:diagnostic imaging*; D015588:Observer Variation; D009942:Organometallic Compounds; D000072078:Positron Emission Tomography Computed Tomography; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D009942:Organometallic Compounds; D019275:Radiopharmaceuticals; C513399:gallium Ga 68 dotatate
keywords: DOTATATE; PET/CT; agreement; interobserver; neuroendocrine tumor; reproducibility