Hein P A, Romano V C, Rogalla P, Klessen C, Lembcke A, Dicken V, Bornemann L, Bauknecht H-C
Institut für Radiologie, Charité Campus Mitte, Charité-Universitätsmedizin Berlin.
Rofo. 2009 Jan;181(1):24-31. doi: 10.1055/s-2008-1027874. Epub 2008 Dec 11.
To compare the interobserver variability of the unidimensional diameter and volume measurements of pulmonary nodules in an intrascan and interscan analysis using semi-automated segmentation software on ultra-low-dose computed tomography (ULD-CT) and standard dose CT (SD-CT) data.
In 33 patients with pulmonary nodules, two chest multi-slice CT (MSCT) datasets (1 mm slice thickness; 20 % reconstruction overlap) had been consecutively acquired with an ultra-low dose (120 kV, 5 mAs) and standard dose technique (120 kV, 75 mAs). MSCT data was retrospectively analyzed using the segmentation software OncoTREAT (MeVis, Bremen, Germany, version 1.3). The volume of 229 solid pulmonary nodules included in the analysis as well as the largest diameter according to RECIST (Response Evaluation Criteria for Solid Tumors) were measured by two radiologists. Interobserver variability was calculated and SD-CT and ULD-CT data compared in an intrascan and interscan analysis.
The median nodule diameter (n = 229 nodules) was registered with 8.2 mm (range: 2.8 to 43.6 mm, mean: 10.8 mm). The nodule volume ranged between 0.01 and 49.1 ml (median 0.1 ml, mean 1.5 ml). With respect to interobserver variability, the intrascan analysis did not reveal statistically significant differences (p > 0.05) between ULD-CT and SD-CT with broader limits of agreement for relative differences of RECIST measurements (-31.0 % + 27.0 % mean -2.0 % for SD-CT; -27.0 % + 38.6 %, mean 5.8 % for ULD-CT) than for volume measurements (-9.4 %, 8.0 %, mean 0.7 % for SD-CT; -13 %, 13 %, mean 0.0 % for ULD-CT). The interscan analysis showed broadened 95 % confidence intervals for volume measurements (-26.5 % 29.1 % mean 1.3 %, and -25.2 %, 29.6 %, mean 2.2 %) but yielded comparable limits of agreement for RECIST measurements.
The variability of nodule volumetry assessed by semi-automated segmentation software as well as nodule size determination by RECIST appears to be independent of the acquisition dose in the CT source dataset. This is particularly important regarding size determination of pulmonary nodules in screening trials using low-dose CT data for follow-up imaging.
使用半自动分割软件，在超低剂量计算机断层扫描（ULD-CT）和标准剂量CT（SD-CT）数据的同层扫描和层间扫描分析中，比较肺结节一维直径和体积测量的观察者间变异性。
对33例肺结节患者，先后采用超低剂量（120 kV，5 mAs）和标准剂量技术（120 kV，75 mAs）连续采集两个胸部多层螺旋CT（MSCT）数据集（层厚1 mm；重建重叠20%）。使用分割软件OncoTREAT（德国不来梅的MeVis公司，版本1.3）对MSCT数据进行回顾性分析。两名放射科医生测量了分析中纳入的229个实性肺结节的体积以及根据实体瘤疗效评价标准（RECIST）得出的最大直径。计算观察者间变异性，并在同层扫描和层间扫描分析中比较SD-CT和ULD-CT数据。
记录的结节中位直径（n = 229个结节）为8.2 mm（范围：2.8至43.6 mm，平均：10.8 mm）。结节体积在0.01至49.1 ml之间（中位值0.1 ml，平均1.5 ml）。关于观察者间变异性，同层扫描分析未显示ULD-CT和SD-CT之间存在统计学显著差异（p > 0.05），RECIST测量相对差异的一致性界限比体积测量更宽（SD-CT为-31.0% + 27.0%，平均-2.0%；ULD-CT为-27.0% + 38.6%，平均5.8%）（SD-CT体积测量为-9.4%，8.0%，平均0.7%；ULD-CT体积测量为-13%，13%，平均0.0%）。层间扫描分析显示体积测量的95%置信区间变宽（-26.5% 29.1%，平均1.3%，以及-25.2%，29.6%，平均2.2%），但RECIST测量的一致性界限相当。
通过半自动分割软件评估的结节体积测量变异性以及根据RECIST确定的结节大小似乎与CT源数据集中的采集剂量无关。这对于在使用低剂量CT数据进行随访成像的筛查试验中确定肺结节大小尤为重要。
