Learning Objectives: Image quality is largely dependent on the pilot study parameters that have been used during scanning. Additional research will be performed to optimize the parameters for CBCT (and the MSCT) in imaging of the temporal bone. Thereafter, a new comparison in optimal settings between the NewTom 5 G (CBCT) and MSCT will be conducted.
Introduction: Multi-slice CT (MSCT) is commonly used as a diagnostic tool for patients with a conductive hearing loss. Recent studies indicate that Cone-beam CT (CBCT) may be used as a low radiation dose alternative for temporal bone imaging. However, limited data are available on the image quality of CBCT compared to MSCT (Casselman, 2013; Theunisse, 2015). The aim of this study was to compare image quality and effective radiation dose of CBCT with MSCT.
Methods: Three human cadaver heads (six ears) were imaged on three CBCT scanners (NewTom 5G, Accuitomo 170 3D, PaX-Zenith 3D) and one MSCT scanner (Discovery CT750 HD Freedom Edition). Visibility of sixteen anatomical landmarks of the middle and inner ear were assessed by two observers on a 4-point Likert scale. Total scores of all landmarks, scores of subgroups (such as the ossicular chain) and individual landmarks were compared. Furthermore, effective radiation dose of the protocols was measured and compared.
Results: Image quality of MSCT and the NewTom 5 G were assessed as superior to the Accuitomo 170 3D and Pax-Zenith 3D (P < 0.05). No significant differences in image quality were found between the MSCT and the NewTom 5G. Similar results between scanners were found when comparing scores of the ossicular chain.
It seems that optimizing the scan settings could further improve the image quality of the NewTom 5 G CBCT.
Effective radiation dosages of CBCT protocols were around 25 percent of the clinical MSCT dose.
Conclusion: Image quality of the NewTom 5 G seems comparable to MSCT when scanning the temporal bone with special attention to the ossicular chain and conductive hearing loss landmarks. Furthermore, CBCT imaging results in a considerably lower effective radiation dose compared to MSCT.