Bolte H, Jahnke T, Schäfer F K W, Wenke R, Hoffmann B, Freitag-Wolf S, Dicken V, Kuhnigk J M, Lohmann J, Voss S, Knöss N, Heller M, Biederer J
Department of Diagnostic Radiology, University Hospital Schleswig-Holstein Campus Kiel, Arnold-Heller Strasse 9, 24105 Kiel, Germany.
Eur J Radiol. 2007 Nov;64(2):285-95. doi: 10.1016/j.ejrad.2007.02.031. Epub 2007 Apr 12.
The aim of this study was to investigate the interobserver variability of CT based diameter and volumetric measurements of artificial pulmonary nodules. A special interest was the consideration of different measurement methods, observer experience and training levels.
For this purpose 46 artificial small solid nodules were examined in a dedicated ex-vivo chest phantom with multislice-spiral CT (20 mAs, 120 kV, collimation 16 mm x 0.75 mm, table feed 15 mm, reconstructed slice thickness 1mm, reconstruction increment 0.7 mm, intermediate reconstruction kernel). Two observer groups of different radiologic experience (0 and more than 5 years of training, 3 observers each) analysed all lesions with digital callipers and 2 volumetry software packages (click-point depending and robust volumetry) in a semi-automatic and manually corrected mode. For data analysis the variation coefficient (VC) was calculated in per cent for each group and a Wilcoxon test was used for analytic statistics.
Click-point robust volumetry showed with a VC of <0.01% in both groups the smallest interobserver variability. Between experienced and un-experienced observers interobserver variability was significantly different for diameter measurements (p=0.023) but not for semi-automatic and manual corrected volumetry. A significant training effect was revealed for diameter measurements (p=0.003) and semi-automatic measurements of click-point depending volumetry (p=0.007) in the un-experienced observer group.
Compared to diameter measurements volumetry achieves a significantly smaller interobserver variance and advanced volumetry algorithms are independent of observer experience.
本研究旨在调查基于CT的人工肺结节直径和体积测量的观察者间变异性。特别关注不同测量方法、观察者经验和培训水平。
为此，在一个专门的离体胸部模型中，用多层螺旋CT（20 mAs，120 kV，准直16 mm×0.75 mm，床速15 mm，重建层厚1mm，重建增量0.7 mm，中等重建核）对46个人工小实性结节进行检查。两组不同放射学经验的观察者（0年及超过5年培训经验，每组3名观察者）采用数字卡尺和2种容积测量软件包（逐点依赖法和稳健容积法），以半自动和手动校正模式分析所有病变。数据分析时，计算每组的变异系数（VC）百分比，并采用Wilcoxon检验进行分析统计。
两组中逐点稳健容积法的观察者间变异性最小，VC<0.01%。在有经验和无经验的观察者之间，直径测量的观察者间变异性有显著差异（p=0.023），但半自动和手动校正容积测量无显著差异。在无经验的观察者组中，直径测量（p=0.003）和逐点依赖容积法的半自动测量（p=0.007）显示出显著的训练效果。
与直径测量相比，容积测量的观察者间方差显著更小，先进的容积算法与观察者经验无关。
