Decoding cholesteatoma radiological dimensions: unveiling the discrepancy between CT and MRI imaging and development of a predictive model based on CT and MRI volume comparison

Background: Cholesteatoma (CHO) presents a significant threat to middle ear integrity, potentially leading to severe complications. Radiological assessment is crucial for understanding CHO anatomy, with high-resolution CT scans commonly used despite limitations in sensitivity and size overestimation. Recent advancements in non-echo planar imaging (EPI) diffusion-weighted imaging (DWI) MRI offer improved sensitivity, but accessibility issues persist. Objectives: The objective of this study is to compare CHO volume, as measured by CT scans, and the gold standard non-EPI DWI MRI. Materials and methods: A prospective clinical trial involving 39 participants with middle-ear CHO compared CT and non-EPI DWI MRI volumes. Patients underwent both imaging modalities, and volumes were measured using a co-registration technique. Results: Median CHO volumes measured by MRI and CT showed a notable difference. The Bland–Altman plot indicated one outlier, removed for further analysis. Linear regression suggested a correlation, with CT volumes overestimating MRI volumes by a factor of four. Conclusions: Our study establishes a formula to estimate CHO size, highlighting the tendency of CT scans to overestimate volumes. While non-EPI DWI MRI remains the gold standard for accurate measurements, our findings emphasize the complementary roles of CT and MRI in CHO diagnosis and post-surgical follow-up through fusion techniques.