Riley, Kalen

Abstract Purpose Failed stapes surgery presents a diagnostic challenge requiring high-resolution imaging to guide revision. Energy-integrating detector CT (EID-CT) is widely used but limited by spatial resolution and metal artifact. Photon-counting CT (PCCT) offers improved spatial resolution and reduced noise, with potential advantages in temporal bone imaging. The purpose of this study was to compare PCCT and EID-CT in identifying etiologies of failed primary stapes surgery, with emphasis on diagnostic accuracy, interobserver agreement, and interpreter confidence Methods In this retrospective study, 38 patients with failed primary stapes surgery who underwent successful revision surgery and pre-revision CT were included; 18 underwent PCCT and 20 underwent EID-CT. Three expert reviewers independently determined the cause of surgical failure, compared against the reference standard of intraoperative findings at revision. Diagnostic accuracy, interobserver agreement (Fleiss kappa), and reader confidence were compared between modalities. Results Overall interobserver agreement was substantially higher with PCCT (κ = 0.75; 95% CI, 0.60–0.90) than EID-CT (κ = 0.44; 95% CI, 0.30–0.59), with improved agreement observed across etiologies of failure; confidence intervals were non-overlapping for overall agreement and ossicular discontinuity. Consensus diagnostic accuracy was comparable between modalities (88.9% PCCT vs 85% EID-CT; p = 1.00), as was interpreter confidence (4.33 PCCT vs 4.17 EID-CT; p = 0.29). Conclusion In this small cohort, PCCT and EID-CT demonstrated similar diagnostic accuracy and reader confidence, whereas PCCT demonstrated significantly higher interobserver agreement, suggesting more reproducible assessment of failed stapes surgery and a potential role in supporting revision surgical planning.