Questionnaires and participants
We generated 10 online questionnaires on Qualtrics (www.qualtrics.com), each containing 18 images out of the image set of 60 images, balanced regarding the three different imaging techniques and presence of cholesteatoma or not (Table 1). We chose 18 images per questionnaire in order to complete the questionnaire in an acceptable time and therefore receive more responses overall, while still allowing a solid statistical analysis. All 60 images were used and every image was present in three different questionnaires.
Thereafter, we reached out to ear surgeons with expertise in cholesteatoma surgery to rate the images regarding the presence of cholesteatoma or not. No additional detailed instructions were sent to the participants. The image enhancement technique was indicated on every image. Moreover, general information (age, gender), details regarding the surgical experience (microscopic and endoscopic ear surgery) as well as subjective preferences regarding the three different imaging modalities were assessed (usefulness on a scale from 1-5 and single choice for one of the three imaging techniques). The study participants were randomly assigned to a questionnaire. After a few weeks, we asked participants to complete the same questionnaire for a second time.