Cartilage thickness: Factors influencing multidetector CT measurements in a phantom study
Cartilage thickness: Factors influencing multidetector CT measurements in a phantom study
复制标题
DOI：
10.1148/radiol.2461062192
复制
发表时间：
2008-01-01
期刊：
影响因子：
19.7
通讯作者：
Weiss, Jeffrey A.
中科院分区：
文献类型：
--
作者：
Anderson, Andrew E.;Ellis, Benjamin J.;Weiss, Jeffrey A.
目的：为了前瞻性地评估在一个幻影的重建误差和检测限的软骨厚度测量获得的多探测器计算机断层扫描（CT）关节造影，作为一个函数的造影剂浓度，扫描方向，空间分辨率，关节间距，和管电流，与已知的测量作为参考standard.Materials和方法：一个幻影与9个腔室构建。每个腔室都有一个尼龙圆柱体，用铝和聚碳酸酯套管包裹，以模拟松质骨、皮质骨和软骨。不同的模拟软骨厚度和10关节间隙宽度进行了评估。在第3天，使用和不使用造影剂注射扫描体模，腔室轴垂直和平行于扫描仪轴。以1.0 mm和0.5 mm的间隔重建图像。改变造影剂浓度和管电流。通过图像分割确定模拟软骨厚度。均方根误差和平均残差用于表征测量结果。CT扫描仪和图像分割结果的再现性determined.Results：模拟软骨大于1.0 mm的厚度重建小于10%的误差时，无论是没有造影剂或低浓度（25%）的造影剂被使用。误差随着造影剂浓度的增加而增加。将模拟关节间隙宽度减小至0.5 mm导致误差略有增加;然而，在关节间隙小于0.5 mm时，误差大幅增加。各向异性CT数据产生的测量误差大于各向同性数据产生的测量误差。改变管电流并没有实质上影响reconstruction errors. Conclusion：该研究揭示了较低的边界和重复性的模拟软骨厚度测量获得通过使用多探测器CT关节造影，并产生相关的数据选择造影剂浓度，关节间隙宽度，扫描方向和空间分辨率，以减少重建误差。
Purpose: To prospectively assess in a phantom the reconstruction errors and detection limits of cartilage thickness measurements obtained with multidetector computed tomographic (CT) arthrography, as a function of contrast agent concentration, scanning direction, spatial resolution, joint spacing, and tube current, with known measurements as the reference standard.Materials and Methods: A phantom with nine chambers was constructed. Each chamber had a nylon cylinder encased by sleeves of aluminum and polycarbonate to simulate trabecular bone, cortical bone, and cartilage. Varying simulated cartilage thicknesses and 10 joint space widths were assessed. On 3 days, the phantom was scanned with and without contrast agent administration and with the chamber axes both perpendicular and parallel to the scanner axis. Images were reconstructed at 1.0-and 0.5-mm intervals. Contrast agent concentration and tube current were varied. The simulated cartilage thickness was determined by using image segmentation. Root mean squared errors and mean residual errors were used to characterize the measurements. The reproducibility of the CT scanner and image segmentation results was determined.Results: Simulated cartilage greater than 1.0 mm in thickness was reconstructed with less than 10% error when either no contrast agent or a low concentration (25%) of contrast agent was used. Error increased as contrast agent concentration increased. Decreasing the simulated joint space width to 0.5 mm caused slight increases in error; however, error increased substantially at joint spaces narrower than 0.5 mm. Errors in measurements derived from anisotropic CT data were greater than errors in measurements derived from isotropic data. Altering the tube current did not substantially affect reconstruction errors.Conclusion: The study revealed lower boundaries and the repeatability of simulated cartilage thickness measurements obtained by using multidetector CT arthrography and yielded data pertinent to choosing the contrast agent concentration, joint space width, scanning direction, and spatial resolution to reduce reconstruction errors.