Original ArticlesInterobserver Variability in the Computed Tomography Assessment of Pulmonary Injury and Tumor Recurrence After Stereotactic Body RadiotherapyGuerreiro, Nicolau F.C. MD*; Araujo-Filho, Jose A.B. MD, PhD*,†; Horvat, Natally MD, PhD*; Lee, Hye Ju MD*; Oliveira, Bernardo S.P. MD*; Ynoe de Moraes, Fabio MD‡,§; Castro, Isac PhD∥; Miranda Degrande, Fabiana Accioli MD‡; Abreu, Carlos E.V. MD, PhD‡; Giassi, Karina de S. MD, PhD*Author Information Departments of *Radiology ‡Radiotherapy ∥Research Hospital Sírio-Libanês, São Paulo, Brazil †Department of Oncology, Division of Radiation Oncology, Queen’s University §Kingston Health Science Centre, Kingston, ON, Canada K.d.S.G. and N.H.: study concepts and study design. J.A.B.A.-F. and K.S.G.: literature search. B.S.P.O., N.F.C.G., and K.d.S.G.: image review. K.d.S.G. and N.F.C.G.: clinical information review. I.C.: statistical analysis. J.A.B.A.-F., N.H., and K.d.S.G.: manuscript drafting and editing. The authors declare no conflicts of interest. Correspondence to: Karina de S. Giassi, MD, PhD, Department of Radiology, Hospital Sírio-Libanês, Rua Dona Adma Jafet, 91, Bela Vista, São Paulo SP 01308-050, Brazil (e-mail: firstname.lastname@example.org). Journal of Thoracic Imaging: September 2020 - Volume 35 - Issue 5 - p 302-308 doi: 10.1097/RTI.0000000000000495 Buy Metrics Abstract Purpose: To evaluate the interobserver agreement of chest computed tomography (CT) findings in the diagnosis of expected changes and local recurrence after stereotactic body radiation therapy (SBRT) in patients with early-stage lung cancer or a single pulmonary metastasis. Materials and Methods: A total of 54 patients with early-stage lung cancer or pulmonary metastasis who were treated with SBRT from 2007 to 2015 were included. The exclusion criteria were patients who presented with pulmonary infection during follow-up and patients who underwent a single CT during follow-up. The imaging features on CT were assessed by 3 blinded radiologists at the following 2 time points after SBRT: (a) early follow-up and (b) late follow-up (≥6 mo). The radiologists classified the findings as expected changes after SBRT or recurrence. Interobserver agreement was assessed by kappa and Wilcoxon statistics. Results: A total of 13 women and 41 men with a mean age of 75.3 (±8.9) years were selected. The total and per fraction SBRT doses were 54 Gy (interquartile range: 45 to 54) and 18 Gy (interquartile range: 15 to 18), respectively. All expected changes and findings suggestive of recurrence had an almost perfect agreement (κ>0.85) among readers, except for diffuse consolidation in the early period (κ=0.65). Conclusion: CT findings demonstrate high interobserver agreement for expected changes and for findings indicating recurrence after SBRT. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.