Department of Oral Medicine and Diagnostic Sciences, College of Dentistry, King Saud University, 60169, Riyadh, 11545, Saudi Arabia.
Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, 60169, Riyadh, 11545, Saudi Arabia.
Int J Comput Assist Radiol Surg. 2018 Nov;13(11):1853-1860. doi: 10.1007/s11548-018-1809-4. Epub 2018 Jun 16.
To compare the surface of computer-aided design (CAD) models of the maxilla produced using ultra-low MDCT doses combined with filtered backprojection (FBP), adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) reconstruction techniques with that produced from a standard dose/FBP protocol.
A cadaveric completely edentulous maxilla was imaged using a standard dose protocol (CTDIvol: 29.4 mGy) and FBP, in addition to 5 low dose test protocols (LD1-5) (CTDIvol: 4.19, 2.64, 0.99, 0.53, and 0.29 mGy) reconstructed with FBP, ASIR 50, ASIR 100, and MBIR. A CAD model from each test protocol was superimposed onto the reference model using the 'Best Fit Alignment' function. Differences between the test and reference models were analyzed as maximum and mean deviations, and root-mean-square of the deviations, and color-coded models were obtained which demonstrated the location, magnitude and direction of the deviations.
Based upon the magnitude, size, and distribution of areas of deviations, CAD models from the following protocols were comparable to the reference model: FBP/LD1; ASIR 50/LD1 and LD2; ASIR 100/LD1, LD2, and LD3; MBIR/LD1. The following protocols demonstrated deviations mostly between 1-2 mm or under 1 mm but over large areas, and so their effect on surgical guide accuracy is questionable: FBP/LD2; MBIR/LD2, LD3, LD4, and LD5. The following protocols demonstrated large deviations over large areas and therefore were not comparable to the reference model: FBP/LD3, LD4, and LD5; ASIR 50/LD3, LD4, and LD5; ASIR 100/LD4, and LD5.
When MDCT is used for CAD models of the jaws, dose reductions of 86% may be possible with FBP, 91% with ASIR 50, and 97% with ASIR 100. Analysis of the stability and accuracy of CAD/CAM surgical guides as directly related to the jaws is needed to confirm the results.
比较使用超低 MDCT 剂量结合滤波反投影（FBP）、自适应统计迭代重建（ASIR）和基于模型的迭代重建（MBIR）重建技术与标准剂量/FBP 协议产生的上颌骨计算机辅助设计（CAD）模型的表面。
使用标准剂量方案（CTDIvol：29.4 mGy）和 FBP 对一具完全无牙上颌骨进行成像，此外还使用 5 种低剂量测试方案（LD1-5）（CTDIvol：4.19、2.64、0.99、0.53 和 0.29 mGy）进行成像，这些方案均采用 FBP、ASIR 50、ASIR 100 和 MBIR 进行重建。使用“最佳拟合对齐”功能将每个测试方案的 CAD 模型叠加到参考模型上。使用最大和平均偏差以及偏差的均方根分析测试和参考模型之间的差异，并获得彩色模型，显示偏差的位置、大小和方向。
基于偏差的大小、大小和分布区域，以下协议的 CAD 模型与参考模型相似：FBP/LD1；ASIR 50/LD1 和 LD2；ASIR 100/LD1、LD2 和 LD3；MBIR/LD1。以下协议显示偏差主要在 1-2 毫米或 1 毫米以下，但面积较大，因此其对上颌骨手术导板准确性的影响值得怀疑：FBP/LD2；MBIR/LD2、LD3、LD4 和 LD5。以下协议显示出大面积的大偏差，因此与参考模型不相似：FBP/LD3、LD4 和 LD5；ASIR 50/LD3、LD4 和 LD5；ASIR 100/LD4 和 LD5。
当 MDCT 用于颌骨 CAD 模型时，FBP 可将剂量减少 86%，ASIR 50 可将剂量减少 91%，ASIR 100 可将剂量减少 97%。需要分析 CAD/CAM 手术导板的稳定性和准确性与颌骨的直接关系，以确认结果。
