Department of Radiology, University of Pittsburgh Medical Center, PA 15213, USA.
AJR Am J Roentgenol. 2011 Mar;196(3):516-23. doi: 10.2214/AJR.10.4603.
The purpose of our study was to assess the accuracy and reproducibility of clot burden quantification with pulmonary CT angiography (CTA).
A semiautomated program was developed for segmentation and volumetric quantification of pulmonary embolus with pulmonary CTA. The accuracy of this measurement method was assessed using two pulmonary embolus phantoms. Reproducibility of the measurement method was assessed using clinical pulmonary CTA in 30 patients (16 women, 14 men; mean age, 62 years) with pulmonary embolism (PE). Two observers segmented and measured the volume of blood clot from pulmonary CTA images twice at two separate sessions. Accuracy was evaluated by the relative volume measurement error. Intra- and interobserver reliability were evaluated using intraclass correlation coefficient (ICC); agreement between measurements within and between the two observers was assessed using Bland-Altman analysis.
Mean relative measurement error from the two phantoms was less than 1% for both observers. A total of 60 emboli were measured from the 30 patients. The intraobserver ICC was 0.990 for observer 1 and 0.999 for observer 2; interobserver ICC was 0.994 for session 1 and 0.989 for session 2. ICC for all four clot measurements was 0.988. Mean volume measurement difference for intraobserver agreement was 0.9% for observer 1 and 0.3% for observer 2, and interobserver agreement was -5.1% for session 1 and -5.8% for session 2.
Blood clot burden can be quantified with a high degree of accuracy and reproducibility from pulmonary CTA images using a semiautomated segmentation method.
我们研究的目的是评估肺 CT 血管造影（CTA）中血栓负荷定量的准确性和可重复性。
开发了一种用于肺 CTA 中肺栓塞分割和体积定量的半自动程序。使用两个肺栓塞模型评估了该测量方法的准确性。使用 30 例（16 名女性，14 名男性；平均年龄 62 岁）肺栓塞（PE）患者的临床肺 CTA 评估了该测量方法的可重复性。两名观察者在两个不同的时间点从肺 CTA 图像上两次分割并测量血栓的体积。准确性通过相对体积测量误差进行评估。使用组内相关系数（ICC）评估观察者内和观察者间的可靠性；使用 Bland-Altman 分析评估两名观察者之间以及两次测量之间的测量一致性。
两名观察者从两个模型中得出的平均相对测量误差均小于 1%。从 30 例患者中总共测量了 60 个栓塞。观察者 1 的观察者内 ICC 为 0.990，观察者 2 的 ICC 为 0.999；第 1 次和第 2 次会话的观察者间 ICC 分别为 0.994 和 0.989。所有四个血栓测量的 ICC 均为 0.988。观察者 1 的内观察者一致性平均体积测量差值为 0.9%，观察者 2 的为 0.3%，第 1 次会话的观察者间一致性为-5.1%，第 2 次会话的为-5.8%。
使用半自动分割方法，从肺 CTA 图像中可以高度准确和可重复地定量血栓负荷。
