da Fonte Juliana B Melo, Fontenele Rocharles Cavalcante, Freitas Deborah Queiroz
Department of Oral and Maxillofacial Radiology, UConn School of Dental Medicine, Farmington, CT, USA.
OMFS IMPATH Research Group, Department of Imaging and Pathology, Faculty of Medicine, KU Leuven, Leuven, Belgium.
Imaging Sci Dent. 2024 Dec;54(4):327-335. doi: 10.5624/isd.20240061. Epub 2024 Aug 25.
This study was performed to evaluate the expression of beam hardening artifacts generated by high atomic number materials in stitched cone-beam computed tomography (CBCT) images, compared to the traditional acquisition mode.
CBCT volumes were acquired using an acrylic resin phantom embedded with pairs of cylinders made from amalgam dental alloy, cobalt-chromium alloy, gutta-percha, titanium, and zirconium. These cylinders were placed within the overlapping zones of the stitching reconstruction area. For each material, 3 acquisitions were conducted: 1 utilizing the automatic stitching process with a FOV of 80×37 mm, and 2 with smaller FOVs of 50×37 mm. For the smaller FOVs, 1 scan targeted the anterior region, while the other focused on the left posterior region. Thus, 3 groups were formed: stitched FOV, anterior FOV, and posterior FOV. Artifact expression was assessed by calculating the means and standard deviations (SDs) of the gray values in 4 regions of interest located anteriorly, posteriorly, medially, and laterally to the cylinders. Analysis of variance was used to compare the data, with an alpha level of 5%.
The stitched FOV exhibited lower SD values than the posterior and anterior FOVs (<0.05). Regarding the materials evaluated, amalgam, cobalt-chromium, and zirconium generally demonstrated higher SDs of the gray values than gutta-percha and titanium (<0.05).
Horizontally stitched CBCT images demonstrated lower artifact expression compared to the traditional mode of acquisition.
本研究旨在评估与传统采集模式相比，高原子序数材料在拼接锥束计算机断层扫描（CBCT）图像中产生的线束硬化伪影的表达情况。
使用嵌入由汞合金牙科合金、钴铬合金、牙胶、钛和锆制成的成对圆柱体的丙烯酸树脂体模采集CBCT容积数据。这些圆柱体放置在拼接重建区域的重叠区内。对于每种材料，进行3次采集：1次使用视野为80×37 mm的自动拼接程序，另外2次使用较小视野50×37 mm。对于较小视野，1次扫描针对前部区域，另1次聚焦于左后部区域。因此，形成了3组：拼接视野组、前部视野组和后部视野组。通过计算位于圆柱体前方、后方、内侧和外侧的4个感兴趣区域内灰度值的均值和标准差（SD）来评估伪影表达。采用方差分析比较数据，α水平为5%。
拼接视野组的SD值低于后部和前部视野组（<0.05）。在所评估的材料中，汞合金、钴铬合金和锆的灰度值SD通常高于牙胶和钛（<0.05）。
与传统采集模式相比，水平拼接的CBCT图像显示出较低的伪影表达。
