Automated Renal Stone Volume Measurement by Noncontrast Computerized Tomography is More Reproducible Than Manual Linear Size Measurement
Automated Renal Stone Volume Measurement by Noncontrast Computerized Tomography is More Reproducible Than Manual Linear Size Measurement
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DOI：
10.1016/j.juro.2011.07.091
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发表时间：
2011-12-01
影响因子：
6.6
通讯作者：
Pickhardt, Perry J.
中科院分区：
文献类型：
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作者：
Patel, Sutchin R.;Stanton, Paul;Pickhardt, Perry J.
目的：我们比较了同一研究中使用仰卧位和俯卧位、低剂量、无对比的计算机断层扫描系列的自动容积和手动线性测量的可重复性。材料和方法：患者队列包括50名平均年龄为56.4岁的连续成人，在计算机断层扫描结肠镜筛查中发现肾结石。每位患者最大结石的评估采用仰卧位和俯卧位计算机断层扫描系列作为相互对照。使用市售的冠状动脉钙评分工具自动计算结石体积。将仰卧位自动容积法的再现性与观察者内仰卧位手动线性测量法进行比较。还评估了同一仰卧位或俯卧位系列的人工线性测量的观察者间变异性。结果：50个指数结石的平均+/- SD线性大小和体积分别为4.5 +/- 2.7 mm（范围1.8 ~ 16）和141.7 +/- 456.1 mm(3)。自动结石体积测量的平均仰卧位误差为16.3%，而人工轴向测量的一维观察者内误差为11.7%。体积误差大于20%的15例中，线性尺寸大于等于5mm的只有2例。同一计算机断层扫描系列的平均观察者间线性误差为26.3%，但同一系列的自动体积测量没有变化。结论：自动非对比计算机断层扫描肾结石体积比人工线性测量更具有可重复性，并且避免了人工评估中经常出现的较大的观察者间差异。由于小的线性差异对应着更大的体积变化，所以更大的绝对体积误差是可以接受的。自动体积测量可能是一种改进的临床参数，用于跟踪肾结石负担。
Purpose: We compared the reproducibility of automated volume and manual linear measurements using same study supine and prone, low dose, noncontrast computerized tomography series.Materials and Methods: The patient cohort comprised 50 consecutive adults with a mean age of 56.4 years in whom renal calculi were identified during computerized tomography colonography screening. The largest stone per patient was assessed with the supine and prone computerized tomography series serving as mutual controls. Automated stone volume was derived using a commercially available coronary artery calcium scoring tool. Supine-prone reproducibility for automated volume was compared with intra-observer supine-prone manual linear measurement. Interobserver variability was also assessed for manual linear measurements of the same supine or prone series.Results: Mean +/- SD linear size and volume of the 50 index calculi was 4.5 +/- 2.7 mm (range 1.8 to 16) and 141.7 +/- 456.1 mm(3), respectively. The mean supineprone error for automated stone volume was 16.3% compared with an average 11.7% 1-dimensional intra-observer error for manual axial measurement. Only 2 of 15 cases with a volume error of greater than 20% were 5 mm or greater in linear size. The average interobserver linear error for the same computerized tomography series was 26.3% but automated volume measurement of the same series did not vary.Conclusions: Automated noncontrast computerized tomography renal stone volume is more reproducible than manual linear size measurement and it avoids the often large interobserver variability seen with manual assessment. Since small linear differences correspond to much larger volume changes, greater absolute volume errors are acceptable. Automated volume measurement may be an improved clinical parameter to use for following the renal stone burden.