Accurate early localization of temporal bone cholesteatoma is essential for determining the most appropriate surgical approach. Dual-layer detector spectral CT (DLCT) with multi-parameter spectral imaging has significantly improved soft tissue resolution. This study aims to investigate the value of dual-layer detector spectral CT multimodal parameters in the localization diagnosis of cholesteatoma of the temporal bone.A retrospective analysis was conducted on dual-layer spectral CT images of 45 patients with middle ear or external auditory canal cholesteatoma, collected between May 2024 and March 2025. The surgeon recorded the extent of cholesteatoma involvement during surgery. Regions of interest (ROIs) were placed on corresponding lesions in different anatomical locations on the spectral CT images, including cholesteatoma tissue and non-cholesteatoma tissues (such as cholesterol granulomas and inflammatory fluids). These lesions were then compared to the histologically and surgically confirmed components at the same anatomical sites. For each ROI, conventional CT value (CTconv), the 40 keV single-energy CT value (CT40 keV), effective atomic number (Zeff), electron density (ED), and the 40-80keV slope (λHU) were recorded and used to compare the DLCT parameters of different pathological components at various anatomical sites.A total of 45 cholesteatoma patients were included in this study, comprising 106 cholesteatoma lesions and 70 non-cholesteatoma lesions. The λHU, CT40 keV, and Zeff showed statistically significant differences between the two groups and demonstrated optimal diagnostic performance, with AUC values of 0.864, 0.856, and 0.869, respectively. The subjective diagnostic accuracy of DLCT for cholesteatoma lesions was 89.8%, with a sensitivity of 82.86%, specificity of 93.33%, positive predictive value (PPV) of 86.14%, and negative predictive value (NPV) of 91.59%. The Kappa value for the agreement with intraoperative findings was 0.809. No significant difference was observed in CTconv and ED between the two groups.Dual-layer detector spectral CT demonstrates high accuracy in the locational diagnosis of temporal bone cholesteatoma. It has significant potential for preoperative evaluation of cholesteatoma lesions, assisting surgeons in selecting the optimal surgical approach.Copyright © 2025 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.