1 Department of Oral Diagnosis, Division of Oral Radiology, Piracicaba Dental School, University of Campinas , Piracicaba , Brazil.
2 Department of Dental Medicine, Bretonneau Hospital, HUPNVS, AP-HP , Paris , France.
Dentomaxillofac Radiol. 2018 Jul;47(6):20180011. doi: 10.1259/dmfr.20180011. Epub 2018 Mar 27.
To assess the influence of artefacts arising from metallic materials in the exomass on cone beam CT (CBCT) voxel values.
CBCT scans were taken of a phantom composed of 16 tubes filled with a homogeneous hyperdense solution and metallic materials of different compositions (titanium, cobalt-chromium and amalgam) and numbers (one, two and three). The phantom was centred in a 5 × 5 cm field of view such that the metallic materials were located in the exomass, using three CBCT units. Voxel values were obtained from the 16 homogeneous areas and averaged. Also, standard deviation was calculated to measure voxel value variability. Analysis of variance in a factorial scheme with additional treatment 3 × 3 + 3 (material × number + control) was performed, followed by Tukey's test for multiple comparisons, and Dunnett's test for comparisons with the control groups, at a level of significance of 5%.
Metallic material in the exomass significantly reduced the mean voxel value in the CS9300 and Picasso Trio units, and increased voxel value variability in all CBCT units. Amalgam was the material that induced significantly greater reduction of the mean voxel value in the CS9300 and Picasso Trio units, and significantly greater increase in the NewTom Giano. Voxel value variability was significantly greater for amalgam in all conditions. The presence of one cylinder induced significantly less pronounced effects on the mean voxel value and voxel value variability.
Artefacts arising from metallic materials in the exomass have a negative influence on CBCT voxel values.
评估外物质中金属材料产生的伪影对锥形束 CT（CBCT）体素值的影响。
对由 16 个充满均匀高密度溶液和不同成分（钛、钴铬和汞齐）和数量（一个、两个和三个）的金属材料的管组成的体模进行 CBCT 扫描。将体模置于 5×5cm 的视野中心，使金属材料位于外物质中，使用三个 CBCT 设备。从 16 个均匀区域中获取体素值并取平均值。还计算了标准偏差以测量体素值的可变性。采用 3×3+3（材料×数量+对照）的析因方案进行方差分析，然后进行 Tukey 多重比较检验和 Dunnett 对照检验，显著性水平为 5%。
外物质中的金属材料显著降低了 CS9300 和 Picasso Trio 单元的平均体素值，并增加了所有 CBCT 单元的体素值可变性。汞齐是在 CS9300 和 Picasso Trio 单元中显著降低平均体素值并在 NewTom Giano 中显著增加体素值可变性的材料。在所有条件下，汞齐的体素值可变性显著更大。一个圆柱体的存在对外物质中平均体素值和体素值可变性的影响较小。
外物质中金属材料产生的伪影对 CBCT 体素值有负面影响。
