Aim: This study compares the objective and subjective appearance of artifacts produced by metal objects inside and outside the limited field of view (FOV) of a common region of interest (ROI). Methods: Metal objects (titanium rods, zirconium rods, and zirconium crucibles) were positioned in the human cadaver’s left maxilla and imaged using Accuitomo 170 cone-beam computed tomography (J Morita, Irvine, CA) with limited FOV. A total of 16 scans (7 with metal inside the FOV, 7 with metal outside the FOV, and 2 controls) were obtained. The artifacts were objectively evaluated by calculating the standard deviation (SD) of grayscale values (GVs) using ImageJ software (National Institutes of Health, Bethesda, MD). For the subjective test, two observers rated paired images for beam hardening/scatter artifacts. Results: There was no statistically significant difference in the SD of GVs between images with metal objects inside and outside the FOV ( P = 0.2882). However, subjective evaluations revealed that beam-hardening artifacts were more pronounced immediately adjacent to metal objects when positioned inside the FOV, affecting 60% of paired images. In addition, slices at the level of metal objects exhibited significantly higher SD of GVs compared to slices apical to the metal objects ( P < 0.001). Conclusion: While repositioning the FOV to exclude metal objects did not significantly reduce image noise in the ROI, it improved artifact appearance in regions immediately adjacent to the metal. These findings suggest that strategic FOV adjustments can enhance diagnostic quality in areas critical for endodontic evaluation.
Chada et al. (Wed,) studied this question.