Rodrigues Andreia Fialho, Campos Marcio José da Silva, Chaoubah Alfredo, Fraga Marcelo Reis, Farinazzo Vitral Robert Willer
*Postgraduate Student, Department of Orthodontics, Juiz de Fora Federal University, Juiz de Fora, Brazil. †Professor, Department of Orthodontics, Juiz de Fora Federal University, Juiz de Fora, Brazil. ‡Professor, Department of Statistics, Juiz de Fora Federal University, Juiz de Fora, Brazil. §Associate Professor and Chair, Department of Orthodontics, Juiz de Fora Federal University, Juiz de Fora, Brazil.
Implant Dent. 2015 Apr;24(2):155-9. doi: 10.1097/ID.0000000000000179.
To determine the effect of field of view (FOV) size on gray values in cone beam computed tomography (CBCT) and multislice computed tomography (MSCT) images.
A phantom made up of 3 cylinders containing distilled water, plaster, and motor oil was constructed and inserted into an acrylic cylinder filled with distilled water. The phantom was scanned with a CBCT and MSCT device using 3 FOV sizes. Gray value of each material was evaluated in 40 axial slices, and the comparison between the results obtained with the same FOV size was made.
In CBCT examinations, there was significant difference between the gray values of different FOVs for the 3 materials. In the MSCT, there was significant difference for the oil. Gray values showed significant difference between the CBCT and MSCT examinations for the 3 materials in the 3 different FOV sizes.
Gray values determined in CBCT images are significantly influenced by the FOV size. Although the gray values obtained in MSCT have shown statistically significant differences between some acquisitions, the analysis of those differences seems to indicate low clinical relevance.
确定视野（FOV）大小对锥束计算机断层扫描（CBCT）和多层螺旋计算机断层扫描（MSCT）图像灰度值的影响。
构建一个由3个分别装有蒸馏水、石膏和机油的圆柱体组成的体模，并将其插入一个装满蒸馏水的丙烯酸圆柱体内。使用3种视野大小，通过CBCT和MSCT设备对该体模进行扫描。在40个轴向切片中评估每种材料的灰度值，并对相同视野大小下获得的结果进行比较。
在CBCT检查中，3种材料在不同视野下的灰度值存在显著差异。在MSCT中，机油的灰度值存在显著差异。在3种不同视野大小下，3种材料在CBCT和MSCT检查之间的灰度值存在显著差异。
CBCT图像中确定的灰度值受视野大小的显著影响。尽管在MSCT中获得的灰度值在某些采集之间显示出统计学上的显著差异，但对这些差异的分析似乎表明其临床相关性较低。
