Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Van Yüzüncü Yıl University, Van, Turkey.
Dentomaxillofac Radiol. 2021 Mar 1;50(3):20200400. doi: 10.1259/dmfr.20200400. Epub 2020 Oct 15.
The purpose of this study was to evaluate the effect of section thickness on volume estimations of bone defects scanned using cone beam computed tomography (CBCT).
25 bone defects were prepared on sheep mandibles and scanned using a KaVo 3D eXam (KaVo Dental, Biberach, Germany) CBCT device. Section thickness of images were reconstructed at 0.25, 0.5, and 0.75 mm to estimate the volume of these defects using the semiautomatic segmentation method. The volume averages obtained using microcomputed tomography and Archimedes' method served as reference values. The estimated volumes at each section thickness were compared with the actual volumes using the Friedman test. The accuracy of volume estimation was determined by the percentage error with respect to the reference values, and the mean absolute error (MAE) was calculated.
Volumetric values of bone defects obtained with CBCT at section thicknesses up to 0.5 mm were compatible with the actual volumes ( > 0.05). The percentage errors at section thicknesses of 0.25, 0.5, and 0.75 mm were -5.4%, -7.3%, and -13.1%, respectively. The mean absolute errors were 13.6 mm, 15.7 mm, and 18.2 mm, respectively.
The section thickness values of CBCT images can be increased to a reasonable level to obtain accurate volume estimation results and save time. The semiautomatic segmentation method can be used reliably for volume estimations of bone defects.
本研究旨在评估锥形束 CT（CBCT）扫描的骨缺损体积估计中层面厚度的影响。
在羊下颌骨上制备 25 个骨缺损，并使用 KaVo 3D eXam（KaVo Dental，Biberach，德国）CBCT 设备进行扫描。将图像的层面厚度重建为 0.25、0.5 和 0.75mm，使用半自动分割方法估计这些缺陷的体积。使用微计算机断层扫描和阿基米德法获得的体积平均值作为参考值。使用弗里德曼检验比较各层面厚度的估计体积与实际体积。用参考值的百分比误差确定体积估计的准确性，并计算平均绝对误差（MAE）。
在层面厚度高达 0.5mm 的情况下，CBCT 获得的骨缺损体积值与实际体积相符（>0.05）。在层面厚度为 0.25、0.5 和 0.75mm 时，百分比误差分别为-5.4%、-7.3%和-13.1%。平均绝对误差分别为 13.6mm、15.7mm 和 18.2mm。
可以增加 CBCT 图像的层面厚度值，以获得准确的体积估计结果并节省时间。半自动分割方法可用于骨缺损的体积估计，具有较高的可靠性。
