Study of artifacts created by metals found through cone beam computed tomography

Abstract

Background: Cone beam computed tomography (CBCT) is of great importance for the diagnosis of the head and neck region and artifacts. The aim of this study was to investigate the effect of metals found by cone beam computed tomography on artifacts and related factors.

Materials and Methods: This descriptive study was conducted using 192 axial section CBCT images of beam hardening artifacts on dry human skulls. The intensity of the artifacts was assessed with regard to the type and number of metals as well as the type of field of view (FOV) and the different distances from the FOV. The chi-square test was used in SPSS version 24.

Results: Kappa coefficient of agreement showed that there is a very good agreement between the observers (P < 0.001 and kappa coefficient = 0.84). The implant had the least "High" artifact severity. Also, the implant had the highest frequency for "No" and "Low" regarding artifact severity. Chrome cobalt and zirconia had a similar situation. Amalgam has the lowest "No" frequency and the most "Moderate" cases (P<0.001). Regarding the number of metals, the results showed that there was a statistically significant relationship between the severity of metal artifacts and the number of metals in which 1 metal had more artifacts. There was no statistically significant relationship between the intensity of metal artifacts and the type of FOV (P > 0.05). Mann-Whitney U test for comparing the mean rank of the artifact intensity in group 1 (0-6 distance) and group 2 (9 distance) or group 3 (14 distance) (P<0.001). There were significant differences regarding the type of distance across artifact severity (P<0.001) in which 6 cm and 14 cm were better because there were highest "No" severity, as well as 0 cm, was worst with the higher "High" severity.

Conclusion: The study found no statistically significant correlation between the intensity of metal artifacts and the field of view (FOV) type, specifically "Full" and "Zoom". However, the analysis did reveal a significant difference in the average rank of artifact intensity among groups based on the distance from the FOV (P<0.001). Notably, the distances of 6 cm and 14 cm exhibited the highest severity of "No" artifacts, indicating better results, whereas the distance of 0 cm had the worst outcome with a higher severity of "High" artifacts. Among different types of metals consisting of zirconia, cobalt chrome, amalgam and implant, the lowest artifact was attributed to implant/titanium. Amalgam showed more artifact severity.