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Background: Non-Echo-Planar Diffusion Weighed Magnetic Resonance Imaging (non-EPI DW MRI) plays a role in the planning of cholesteatoma surgery.

Objectives: To outline the usage of Non-EPI DW MRI in cholesteatoma diagnostics and to determine its accuracy, using otosurgery diagnostics as reference standard. Material and

Methods: A retrospective descriptive study. All subjects operated, with suspicion of cholesteatoma as indication, that had a preceding examination with non-EPI DW MRI, between October 2010 and March 2019. Calculating sensitivity, specificity, predicative values, and likelihood ratios, using non-EPI DW MRI as index test and diagnosis from otosurgery as reference standard.

Results: Fifty-two subject episodes were included. Non-EPI DW MRI had a sensitivity of 0.50, specificity of 0.75, positive and negative predictive values of 0.74 and 0.52 and, positive and negative likelihood ratios of 2.0 and 0.67 respectively.

Conclusions and Significance: There is a clear annual trend with increased numbers of executed examinations during the study period. The diagnostic accuracy of non-EPI DW MRI does not reach acceptable levels in the existing everyday routine practice conditions. The accuracy of the examination increases when interpreted by an experienced radiologist and when using the definition of cholesteatoma recommended by EAONO/JOS.