Gietema Hester A, Wang Ying, Xu Dongming, van Klaveren Rob J, de Koning Harry, Scholten Ernst, Verschakelen Johny, Kohl Gerhard, Oudkerk Matthijs, Prokop Mathias
Department of Radiology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
Radiology. 2006 Oct;241(1):251-7. doi: 10.1148/radiol.2411050860. Epub 2006 Aug 14.
To retrospectively determine interobserver variability of semiautomated volume measurements of pulmonary nodules and the potential reasons for variability.
The Dutch-Belgian lung cancer screening trial (NELSON) is a lung cancer screening study that includes men between the ages of 50 and 75 years who are current or former heavy smokers. The NELSON project was approved by the Dutch Ministry of Health and the ethics committee of each participating hospital. Informed consent was obtained from all participants. For this study, the authors evaluated 1200 consecutive low-dose computed tomographic (CT) scans of the chest obtained during the NELSON project and identified subjects who had at least one 50-500-mm(3) nodule. One local and one central observer independently evaluated the scans and measured the volume of any detected nodule by using semiautomated software. Noncalcified solid nodules with volumes of 15-500 mm(3) were included in this study if they were fully surrounded by air (intraparenchymal) and were detected by both observers. The mean volume and the difference between both measurements were calculated for all nodules. Intermeasurement agreement was assessed with the Spearman correlation coefficient. Potential reasons for discrepancies were assessed.
There were 232 men (mean age, 60 years; age range, 52-73 years) with 430 eligible nodules (mean volume, 77.8 mm(3); range, 15.3-499.5 mm(3)). Interobserver correlation was high (r = 0.99). No difference in volume was seen for 383 nodules (89.1%). Discrepant results were obtained for 47 nodules (10.9%); in 16 cases (3.7%), the discrepancy was larger than 10%. The most frequent cause of variability was incomplete segmentation due to an irregular shape or irregular margins.
In a minority (approximately 11%) of small solid intraparenchymal nodules, semiautomated measurements are not completely reproducible and, thus, may cause errors in the assessment of nodule growth. For small or irregularly shaped nodules, an observer should check the segmentation shown by the program.
回顾性确定肺结节半自动体积测量的观察者间变异性及其变异的潜在原因。
荷兰-比利时肺癌筛查试验（NELSON）是一项肺癌筛查研究，纳入年龄在50至75岁之间的现吸烟者或既往重度吸烟者男性。NELSON项目得到荷兰卫生部及各参与医院伦理委员会的批准。所有参与者均获得知情同意。在本研究中，作者评估了NELSON项目期间获得的1200例连续胸部低剂量计算机断层扫描（CT），并确定至少有一个50 - 500立方毫米结节的受试者。一名本地观察者和一名中心观察者独立评估扫描图像，并使用半自动软件测量任何检测到的结节的体积。如果体积为15 - 500立方毫米的非钙化实性结节完全被空气包围（实质内）且被两名观察者均检测到，则纳入本研究。计算所有结节的平均体积以及两次测量之间的差异。用Spearman相关系数评估测量间的一致性。评估差异的潜在原因。
有232名男性（平均年龄60岁；年龄范围52 - 73岁），有430个符合条件的结节（平均体积77.8立方毫米；范围15.3 - 499.5立方毫米）。观察者间相关性较高（r = 0.99）。383个结节（89.1%）的体积未见差异。47个结节（10.9%）得到不一致的结果；16例（3.7%）差异大于10%。变异性最常见的原因是由于形状不规则或边缘不规则导致的分割不完全。
在少数（约11%）小的实质内实性结节中，半自动测量不完全可重复，因此可能在结节生长评估中导致误差。对于小的或形状不规则的结节，观察者应检查程序显示的分割情况。
