The e-learning was specifically designed for the study. It consisted of two parts. The first part incorporated a short repetition of sinus anatomy, basic principles of imaging techniques of the paranasal sinuses and CT anatomy and anatomical variants of the paranasal sinuses and their clinical relevance. The e-learning consisted of slides with theoretical content and imaging examples (Fig. 1a,b).
The second part of the e-learning introduced the CLOSE mnemonic and the different structures were illustrated on different CT images.
Medical students were asked to participate in the study. All students were 5th -year medical students. We chose senior students as they have sufficient knowledge of anatomy and an advanced level of theoretical medical knowledge, comparable to junior doctors, but only little professional experience. Therefore, they are well suited to assess the effectiveness of e-learning to transfer complex learning contents such as CT anatomy of the paranasal sinuses. They were previously only taught basic CT anatomy during the lecture on nose and paranasal sinuses, which is held as a combined lecture of anatomy, radiology and clinical otorhinolaryngology.
After the students gave their informed consent, the first part of the e-learning was distributed by e-mail. During a first session, ten anonymized CT scans of patients in two to three planes (axial, coronal and sagittal if available) were presented to the students to be checked for anatomical variants. The scans were presented in a regular CT viewer, where the students could scroll through the images in different planes. A total of 18 anatomical variants were present in these scans. The students could scroll through the images on an individual computer and there was no time restriction for the assessment of the scans.
After this session, the second e-learning module was distributed by e-mail. In the following session, the students were asked to review the same 10 CT scans again, utilizing the CLOSE mnemonic as a CT checklist. To reduce the risk of a learning effect assessing the same CT scans, the students were not told if their answers during the first session were correct and there were at least 4 weeks in between the two session.
After the second session, the students completed a subjective evaluation form regarding the usefulness of the checklist (modified from [21]). The included items are presented in Table 1. The items were rated on a 4 point Likert scale (1 = strongly agree, 2 = agree, 3 = disagree, 4 = unsure).
Table 1
Subjective evaluation of the usefulness of the CLOSE criteria and e-learning.
Item 1 | The checklist is useful |
Item 2 | The checklist makes sure, that I spend enough time reviewing the CT scans |
Item 3 | The checklist makes me more confident in dealing with sinus anatomy and CT scans of the paranasal sinuses |
Item 4 | The e-learning was appropriate to introduce the topics |
The study was conducted according to national regulations and the declaration of Helsinki. The study was approved by the local ethics committee of the University.
The participants were given an information sheet about the study and gave written informed consent. They were also informed about their rights according to current data protection regulation and gave written consent for the collection, analysis and storage of their personal data.
The percentage of correctly identified anatomical variants before and after implementation of the CLOSE criteria were compared. Eighteen variants were rated as 100%. We also evaluated each CLOSE item separately. The 10 CT scans included two variants of the cribriform plate, six of the lamina papyracea, four Onodi cells, two variants of the sphenoid sinus and two of the anterior ethmoidal artery. There were two scans with concha bullosa, which were rated in the total score of anatomical variants but not the individual items as they are not included in the CLOSE mnemonic.
We previously performed the same study with junior and senior otolaryngology residents in our institution [23]. Twelve residents were shown the same ten CT scans as the students before and after the implementation of the CLOSE criteria. In contrast to the students, they were not given an introduction to the topic before the first session as we wanted to evaluate the knowledge they acquired during their training. The CLOSE criteria were introduced during a formal teaching session. We further interpreted the residents’ results by analyzing the individual CLOSE items and compared the results of students and residents.
Statistical analysis was performed with IBM SPSS Statistics (IBM Corp. Released 2015. IBM SPSS Statistics for Windows, Version 24.0, Armonk, NY: IBM Corp.).
Comparison between data was computed using the Wilcoxon-test and statistical significance was set at a p-value of < 0.05. The comparisons were calculated with the Levene-test to define homo- versus heterogeneous variance and the T-test to define statistically significant differences. Graphs were compiled with Excel (Microsoft).
Descriptive data analysis was performed for the results of the evaluation form. Minimum, maximum, mean and standard deviation for each item of the evaluation form were calculated.