[The effectiveness of CT-MRI image fusion technology in the preoperative assessment of middle ear cholesteatoma]

Objective: To evaluate the effectiveness of CT-MRI image fusion technology in the preoperative assessment of middle ear cholesteatoma. Methods: The clinical data of patients with middle ear cholesteatoma who underwent surgery at Guangdong Provincial People's Hospital from September 2018 to January 2020 were retrospectively analyzed. Preoperative CT and MRI of the patients were automatically fused using the open-source software 3D Slicer, followed by 3D reconstruction of the fused inner ear structures. The degree of overlap was assessed and scored to evaluate the image fusion quality, with manual adjustments made for cases with poor fusion. The value of CT-MRI image fusion technology in the preoperative assessment of middle ear cholesteatoma was then analyzed. Results: A total of 27 patients (12 males and 15 females) aged (40.0±16.2) years were included. The fusion effect was satisfactory (score≥3) in 21 cases and poor (score<3) in 6 cases. After manual adjustments, all 6 cases achieved a satisfactory fusion effect (score≥3). The area under the receiver operating characteristic curve (AUC) values for diagnosing the extent of invasion of middle ear cholesteatoma in the retrotympanic and mastoid regions using CT, MRI, and CT-MRI fused images were 0.621 (95%CI: 0.404-0.838), 0.803 (95%CI: 0.638-0.969), and 0.841 (95%CI: 0.693-0.990), respectively, with the sensitivity of 94.1%, 70.6% and 88.2%, the specificity of 30.0%, 90.0% and 80.0%, and the accuracy of 70.4%, 77.8% and 85.2%, respectively. Conclusions: The 3D reconstruction of inner ear structures can be used to assess and refine the fusion quality of CT-MRI images. This CT-MRI image fusion technology is valuable for the preoperative localization assessment of middle ear cholesteatoma.