Evaluation of artifacts created by metal materials in the exomass in cone beam computed tomography imaging

Abstract

Introduction and Objective: CBCT has a high importance in the diagnosis and treatment plan of the head and neck. Artifacts, including metal-related artifacts, also have important effects in the field of view (FOV) on the image quality and clutter, as well as difficulty of diagnosis. The present study was performed to examine out-of-FOV metal artifacts (exomass) with respect to the number of metals, two types of FOV, and different exomass distances. Materials and Methods: In this descriptive-analytical study, 192 images of CBCT scans in the axial section of beam hardening artifacts were prepared and examined by irradiating on a dry human skull. The artifact intensity was assessed based on the type, number of restorative material, types of FOV, and different distances from the FOV by Chi-square test and SPSS 24 software. Findings: Results of the artifact intensity and the type of restorative material in the axial view were expressed as P-value = 0.001. Based on the number of restorative material, the highest artifact intensity was observed in the placement of one numder with a frequency of 9.4%. A comparison of FULL and ZOOM FOVs revealed a P-value of 0.899. Results of the artifact intensity based on different out-of-FOV (exomass) distances were reported with P-value < 0.01. Conclusion: In this study, the highest and the lowest intensities of artifacts were observed with amalgam and titanium, respectively. In terms of the number and placement, the highest and the lowest intensities were observed in one and two restorative material placements, respectively, due to dissimilar thickness of simulated soft tissue relative to the position of metals. No significant results were obtained by a comparison of FULL and ZOOM FOVs. In terms of different distances from the FOV, the highest artifact intensity was obtained at the edge of the FOV (0 cm) and no artifact was observed at a distance of 14 cm from the edge of the FOV.