Division of Oral and Maxillofacial Radiology, Department of Oral Medicine and Diagnostic Sciences, College of Dentistry, King Saud University, PO Box 60169, Riyadh, 11545, Saudi Arabia.
Division of Clinical and Functional Anatomy, Medical University of Innsbruck, Müllerstrasse 59, 6020, Innsbruck, Austria.
Oral Radiol. 2019 Sep;35(3):280-286. doi: 10.1007/s11282-018-0350-z. Epub 2018 Oct 13.
To assess the linear measurements of edentulous ridges recorded from multidetector row computed tomography (MDCT) images obtained by a previously untested ultra-low dose in combination with filtered back-projection (FBP), adaptive statistical iterative reconstruction (ASIR), and model-based iterative reconstruction (MBIR).
Three cadavers were imaged using a reference protocol with a standard dose and FBP (volume CT dose index (CTDIvol): 29.4 mGy) and two ultra-low-dose protocols, LD1 and LD2 (CTDIvol: 0.53 and 0.29 mGy). All test examinations were reconstructed with FBP, ASIR 50, ASIR 100, and MBIR. Linear measurements from the images of the edentulous ridges recorded from the test protocols were compared with those from the reference using a one-sample t test, Bland-Altman plots, and linear regression. Statistical significance was set at a p value of 0.05.
The one-sample t test demonstrated a statistically significant difference between the measurements from the reference protocol and all test protocols. The difference was not clinically significant for the following three test protocols: LD1/FBP, LD1/ASIR 50, and LD2/FBP. Bland-Altman plots with linear regression showed no systematic variation between the measurements obtained with the reference protocol and these three test protocols.
The lowest-dose protocol to demonstrate comparable measurements with a standard MDCT dose was CTDIvol 0.29 mGy with FBP. These results must be considered with caution for areas of the jaws with thin cortication. The results in areas of thin cortication should be verified by studies with larger sample sizes at such areas and comparison with true gold standard measurements.
评估通过未经测试的超低剂量与滤波反投影（FBP）、自适应统计迭代重建（ASIR）和基于模型的迭代重建（MBIR）相结合的多排螺旋 CT（MDCT）图像记录的无牙颌牙槽嵴的线性测量值。
对 3 具尸体使用参考方案进行成像，标准剂量和 FBP（容积 CT 剂量指数（CTDIvol）：29.4 mGy），以及两种超低剂量方案 LD1 和 LD2（CTDIvol：0.53 和 0.29 mGy）。所有测试检查均采用 FBP、ASIR50、ASIR100 和 MBIR 进行重建。使用单样本 t 检验、Bland-Altman 图和线性回归比较从测试方案记录的无牙颌牙槽嵴图像的线性测量值与参考值。统计学意义设定为 p 值<0.05。
单样本 t 检验显示参考方案与所有测试方案的测量值之间存在统计学显著差异。对于以下三个测试方案，差异无临床意义：LD1/FBP、LD1/ASIR50 和 LD2/FBP。Bland-Altman 图与线性回归显示参考方案与这三个测试方案获得的测量值之间没有系统变化。
与标准 MDCT 剂量相比，显示可比测量值的最低剂量方案为 CTDIvol 0.29 mGy 与 FBP。这些结果必须谨慎考虑颌骨皮质较薄的区域。在皮质较薄的区域，应通过更大样本量的研究和与真实金标准测量值的比较来验证结果。
