Considerations in measuring cartilage thickness using MRI: factors influencing reproducibility and accuracy
Considerations in measuring cartilage thickness using MRI: factors influencing reproducibility and accuracy
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DOI：
10.1016/j.joca.2005.04.013
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发表时间：
2005-09-01
影响因子：
7
通讯作者：
Andriacchi, TP
中科院分区：
文献类型：
--
作者：
Koo, S;Gold, GE;Andriacchi, TP
目的：本研究的主要目的是描述和评估可能影响磁共振成像（MRI）测量膝关节负重区体内软骨厚度的精度和准确性的条件。设计：从分割的MR图像中创建股骨软骨的三维（3D）模型。选择股骨软骨承重区域作为行走时维持接触的胫股关节部分。六个感兴趣的区域（每个髁上三个）位于股骨上。计算每个区域的平均软骨厚度。利用mri衍生3D模型的软骨厚度测量的观察者内部和观察者之间的可重复性测试来评估测量精度对观察者变异性的敏感性。此外，使用观察者间可重复性协议评估了基于规则的分割协议的定量影响。通过对猪膝盖承重和非承重区域的MR图像和激光扫描的3D模型进行比较，对猪膝盖进行了准确性测试。结果：观察者内检验的精确度（变异系数(CV) = 1-3%）明显优于观察者间检验。添加基于规则的方案大大降低了观察者间试验的可变性（CV = 6.6% vs 8.3%）。精度测试表明，各髁上的中心和承重区域比边界和非承重区域精度更高。此外，这些结果表明，在确定有软骨变性的负重区软骨厚度时应该小心，因为在MR图像中，较薄的软骨厚度可能被系统地高估。结论：基于规则的方法在测量多个观察者的软骨厚度时可以大大增加观察者之间的可重复性。这种观察者间可重复性的提高可能是疾病进展纵向研究的重要考虑因素。在定量软骨厚度时，每个髁上的中心和负重区域比边界和非负重区域能提供更精确的测量，平均精度为+/- 0.2-0.3 mm。本研究的一个重要发现是，通常具有最大临床意义的负重区域，矢状面成像测量最准确。(c) 2005年国际骨关节炎研究学会。Elsevier Ltd.出版。版权所有。
Objective: The primary goal of this study was to describe and evaluate conditions that could influence the precision and accuracy of measuring in vivo cartilage thickness in the weight bearing regions of the knee from magnetic resonance imaging (MRI).Design: Three-dimensional (3D) models of the femoral cartilage were created from segmented MR images. The weight bearing regions on femoral cartilage were selected for the portion of the tibiofemoral joint that sustains contact during walking. Six regions of interest (three on each condyle) were located on the femur. Average cartilage thickness was calculated over each region. The sensitivity of the precision of the measurements to observer variability was evaluated using intra- and inter-observer reproducibility tests of cartilage thickness measurements from the MRI-derived 3D models. In addition, the quantitative influence of a rule-based protocol for segmentation was evaluated using the inter-observer reproducibility protocol. Accuracy tests were conducted on porcine knees by comparing 3D models from MR images and laser scans across weight bearing and non-weight bearing regions.Results: The precision was substantially better for the intra-observer tests (Coefficient of variation (CV) = 1-3%) than the inter-observer tests. Adding a rule-based protocol reduced variability in inter-observer tests substantially (CV = 6.6% vs 8.3%). Accuracy tests showed that the central and weight bearing regions on each condyle were more accurate than boundary and non-weight bearing regions. In addition, these results indicate that care should be taken when determining cartilage thickness of weight bearing regions with cartilage degenerations, since the thickness of thinner cartilage can be systematically overestimated in MR images.Conclusions: A rule-based approach can substantially increase inter-observer reproducibility when measuring cartilage thickness from multiple observers. This improvement in inter-observer reproducibility could be an important consideration for longitudinal studies of disease progression. In quantifying cartilage thickness, central and weight bearing regions on each condyle can provide more accurate measurement than boundary and non-weight bearing regions with average accuracy of +/- 0.2-0.3 mm. An important finding of this study was that the weight bearing regions, which are usually of the greatest clinical interest, were measured most accurately by sagittal plane imaging. (c) 2005 OsteoArthritis Research Society International. Published by Elsevier Ltd. All rights reserved.