Incidental findings on cbct by field of view and presence or absence on 2d images

BACKGROUND It has been well documented that the frequency of incidental findings in cone beam computed tomography (CBCT) scans is relatively high. These incidental findings range from low to high significance. Research has shown that many of these findings are not detected on 2D computed tomography or CBCT. CBCT scans vary from small to large field of view (FOV). One strategy to reduce the number of incidental findings and liability is to decrease the FOV. OBJECTIVE(S) The aim of this study was to record what significant incidental findings can be seen on 2D intraoral imaging that were reported on CBCT imaging. A second aim was to compare the frequency of significant incidental findings in multiple CBCT fields of view. STUDY DESIGN CBCT reports at the University of North Carolina between 2017 and 2019 were reviewed. Reports included scans taken on the Orthophos SL 3D and 1 of 3 FOVs (5 × 5 × 6, 8 × 8 × 8, 11 × 11 × 10). A total of 170 reports for each of the 3 FOVs were used, for a total of 510 reports. For each report all significant incidental findings were recorded. Two-dimensional intraoral and panoramic images taken within 1 year of the CBCT were reviewed by 2 oral and maxillofacial radiologists to determine visibility on 2D imaging. RESULTS A total of 673 significant incidental findings were reported. The frequency of significant incidental findings changed significantly between 5 × 5 × 6 (101) and 8 × 8 × 8 (275) but did not change significantly between 8 × 8 × 8 (275) and 11 × 11 × 10 (297). The different types of incidental findings increased with all 3 FOVs. Detection frequency of incidental findings in CBCT that were also found in 2D radiographs were 5 × 5 × 6 (34%), 8 × 8 × 8 (36%), and 11 × 11 × 10 (40%). DISCUSSION/CONCLUSIONS The frequency of type of incidental findings increases with increasing FOV from 5 × 5 × 6 to 8 × 8 × 8 or 11 × 11 × 10. A large portion of incidental findings detected on CBCT are not detected on 2D imaging.