Image retake rates of cone beam computed tomography in a dental institution

Objectives: To investigate the frequency and reasons for retaking cone beam computed tomography (CBCT) scans in an oral and maxillofacial radiology imaging clinic in a dental institution.

Materials and methods: A retrospective cohort chart audit of the patient image database was performed for 1737 patients attending the Diagnostic Imaging clinic at the Prince Philip Dental Hospital from February 2016 to May 2019, and the rate of, and reasons for, CBCT image re-exposure was tallied. Patient demographics (age and gender) and CBCT acquisition parameters (CBCT unit, field-of-view (FOV), scanned region of interest, and exposure time) were recorded and correlated to retake analysis.

Results: The retake rate was 4.6% (80/1737). The most common reasons for re-exposure were incomplete FOV coverage (57.5%) and motion artifacts (27.5%). Patients under 12 years of age had a significantly higher risk for motion artifacts. CBCT for the temporomandibular joint (TMJ) had a significantly higher risk for incomplete FOV coverage.

Conclusions: Children (less than 12 years of age) demonstrate a higher frequency of retakes, principally due to motion artifacts. TMJ CBCT examinations have a higher frequency of retakes due to an incomplete FOV coverage.

Clinical relevance: Information regarding the frequency and reasons for CBCT retakes is beneficial to identify procedures, practices, or patients susceptible to additional radiation exposure and implement appropriate and specific quality control protocols.