Helical Multidetector Row Quantitative Computed Tomography (QCT) Precision
Helical Multidetector Row Quantitative Computed Tomography (QCT) Precision
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DOI：
10.1016/j.acra.2008.08.007
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发表时间：
2009-02-01
影响因子：
4.8
通讯作者：
Cody, Dianna D.
中科院分区：
文献类型：
--
作者：
Bligh, Michael;Bidaut, Luc;Cody, Dianna D.
基本原理和目标。不同的图像采集参数对定量计算机断层扫描测量精度的影响目前是基于螺旋图像采集和多探测器行扫描仪出现之前进行的研究。本研究的目的是评估螺旋多检测器行定量计算机断层扫描，以确定影响使用当前老式计算机断层扫描（CT）进行的定量计算机断层扫描测量总体精度的因素。材料与方法。CT协议参数（x射线管电压和电流、螺距、龙门旋转速度、检测器配置、工作台高度和重建算法）和短期扫描仪变化的影响在两种市售定量CT （QCT）系统（即参考模型和分析软件的组合）上进行了检查，使用7台多检测器行CT扫描仪（可从单一供应商获得）在螺旋模式下运行。结合使用三个离体脊柱标本模拟患者重新定位，根据“最佳情况”、“常规情况”和“最坏情况”三种情况进行精度（变异系数）估计。在不允许改变骨密度（BMD）扫描方案的情况下，总体最佳情况下QCT精度为1.4%。常规病例检查（有BMD参考幻影）允许x射线管电流和工作台速度的一些变化，准确度为1.8%。在不受临床QCT检查约束的情况下，最坏情况的准确率估计为3.6%。虽然表面上看起来很小，但这些误差是针对单个时间点的，当通过多个时间点的QCT测量监测变化时，这些误差可能会大幅增加。这要求在使用螺旋多检测器行定量计算机断层扫描评估BMD变化时更加谨慎和注意细节。
Rationale and Objectives. The impact of varying image acquisition parameters on the precision of measurements using quantitative computed tomography is currently based on studies performed before the advent of helical image acquisition and multidetector-row scanners. The aim of this study was to evaluate helical multidetector-row quantitative computed tomography to determine the factors contributing to the overall precision of measurements on quantitative computed tomography conducted using current vintage computed tomographic (CT) scanners.Materials and Methods. The effects of CT protocol parameters (x-ray tube voltage and current, pitch, gantry rotation speed, detector configuration, table height, and reconstruction algorithm) and short-term scanner variation were examined on two commercially available quantitative CT (QCT) systems (ie, a combination of reference phantoms and analysis software) using seven multidetector-row CT scanners (available from a single vendor) operated in helical mode. Combined with simulated patient repositioning using three ex vivo spine specimens, precision (coefficient of variation) estimates were made on the basis of three scenarios: "best case," "routine case," and "worst case."Results. The overall best-case QCT precision was 1.4%, provided that no changes were permitted to the bone mineral density (BMD) scan protocol. Routine-case examination (with a BMD reference phantom in place) that permitted some variation in the x-ray tube current and table speed produced a precision of 1.8%. Without any constraints on the clinical QCT examinations, the worst-case precision was estimated at 3.6%.Conclusions. Although small in appearance, these errors are for single time points and may increase substantially when monitoring changes through QCT measurements over several time points. This calls for increased caution and attention to detail whenever using helical multidetector-row quantitative computed tomography for the assessment of BMD change.