Department of Oral Diagnosis, Division of Oral Radiology, Piracicaba Dental School, University of Campinas, Piracicaba, Brazil.
Department of Imaging and Pathology, OMFS IMPATH Research Group, Faculty of Medicine, KU Leuven, Leuven, Belgium.
Dentomaxillofac Radiol. 2023 Oct;52(7):20230147. doi: 10.1259/dmfr.20230147. Epub 2023 Sep 4.
To compare cylindrical and convex triangular field-of-views (FOVs) concerning the magnitude of artefacts from high-density materials in cone-beam CT (CBCT).
Cylinders of amalgam, chromium-cobalt, titanium, and zirconia were individually placed in the anterior and posterior regions of a polymethylmethacrylate phantom and scanned using cylindrical and convex triangular FOVs of the Veraview X800 CBCT device. Using the Image J software, 15 square regions of interest (ROIs) were placed in the axial reconstruction around the middle level of the cylinder and at distances of 0.5, 1.0, and 1.5 cm from the centre of the cylinder. Mean grey value and standard deviation of each ROI were averaged for each distance and subtracted from the values of a control ROI to calculate the magnitude of the artefacts by the grey value mean difference (GVMD) and grey value standard deviation (GVSD). Multiway analysis of variance with Tukey test with a significance level of 5% evaluated the effect of the shape of the FOV, position inside the FOV, high-density material, and the distance of the artefact from the material.
The convex triangular FOV increased the GVSD for all materials in the anterior and posterior regions at 0.5 cm compared to the cylindrical FOV ( < 0.0001). The convex triangular FOV showed greater GVMD for chromium-cobalt and zirconium in the anterior region and all materials in the posterior region at all distances ( < 0.0001).
The FOV shape influences the magnitude of artefacts from high-density materials. The convex triangular FOV showed greater artefact magnitude with variability among the high-density materials, region in the FOV, and distance from the material.
比较柱状和凸面三角视野（FOV）在锥形束 CT（CBCT）中高密度材料伪影程度的差异。
将汞合金、铬钴、钛和氧化锆的圆柱体分别放置在聚甲基丙烯酸甲酯体模的前区和后区，并使用 Veraview X800 CBCT 设备的柱状和凸面三角 FOV 进行扫描。使用 Image J 软件，在圆柱体的中间水平的轴向重建图像周围以及距圆柱体中心 0.5、1.0 和 1.5 cm 处的 15 个感兴趣区域（ROI）放置 15 个 ROI。为每个距离计算每个 ROI 的平均灰度值和标准差，并从控制 ROI 的值中减去，以计算灰度值均值差（GVMD）和灰度值标准差（GVSD）表示的伪影程度。采用具有 5%显著水平的多因素方差分析和 Tukey 检验评估 FOV 形状、FOV 内部位置、高密度材料和伪影距材料的距离对 GVMD 和 GVSD 的影响。
与柱状 FOV 相比，凸面三角 FOV 在 0.5 cm 处增加了前区和后区所有材料的 GVSD（ < 0.0001）。在 0.5 cm 处，凸面三角 FOV 在前区显示出铬钴和氧化锆以及后区所有材料的 GVMD 更高（ < 0.0001）。
FOV 形状会影响高密度材料的伪影程度。凸面三角 FOV 显示出更高的伪影程度，并且伪影程度在高密度材料、FOV 区域和距材料的距离方面存在差异。
