Scout images acquired prior to cone beam CT acquisitions: reproducibility of findings and added diagnostic information.

Objectives: The aim of the present study was to assess the reproducibility of findings in cone beam CT (CBCT) scout images. Furthermore, the study aimed to assess whether a scout image shows pathology not seen within the CBCT volume (ie, added diagnostic information) and therefore must be assessed on the same terms as the full volume.

Methods: Using a retrospective design, 233 CBCT reports and scout images were assessed. Kappa statistics and percentage of accordance were used to evaluate intra- and inter-observer reproducibility as well as agreement between scout and CBCT report.

Results: Intra- and inter-observer reproducibility was overall low (kappa ranging from -0.008 to 1.000). Agreement between findings reported in the CBCT and scout was also low. One hundred fourteen impacted teeth, one apical periodontitis, and two sinus conditions seen in the scout image were not registered in the full volume report due to the extended size of the scout image.

Conclusions: Reproducibility of findings in scout images compared to CBCT volumes was low, and the scout showed very little additional diagnostic information.

Advances in knowledge: This study shows that although the reproducibility of viewing scout images is low, rare findings can go undetected if the scout is not assessed. Legislation regarding interpretation of scout images needs to be discussed.