Hein P A, Rogalla P, Klessen C, Lembcke A, Romano V C
Institut für Radiologie, Charité Campus Mitte, Charité-Universitätsmedizin Berlin.
Rofo. 2009 Nov;181(11):1056-64. doi: 10.1055/s-0028-1109394. Epub 2009 Jun 17.
To evaluate the impact of dose reduction on the performance of computer-aided lung nodule detection systems (CAD) of two manufacturers by comparing respective CAD results on ultra-low-dose computed tomography (ULD-CT) and standard dose CT (SD-CT).
Multi-slice computed tomography (MSCT) data sets of 26 patients (13 male and 13 female, patients 31 - 74 years old) were retrospectively selected for CAD analysis. Indication for CT examination was staging of a known primary malignancy or suspected pulmonary malignancy. CT images were consecutively acquired at 5 mAs (ULD-CT) and 75 mAs (SD-CT) with 120 kV tube voltage (1 mm slice thickness). The standard of reference was determined by three experienced readers in consensus. CAD reading algorithms (pre-commercial CAD system, Philips, Netherlands: CAD-1; LungCARE, Siemens, Germany: CAD-2) were applied to the CT data sets.
Consensus reading identified 253 nodules on SD-CT and ULD-CT. Nodules ranged in diameter between 2 and 41 mm (mean diameter 4.8 mm). Detection rates were recorded with 72 % and 62 % (CAD-1 vs. CAD-2) for SD-CT and with 73 % and 56 % for ULD-CT. Median false positive rates per patient were calculated with 6 and 5 (CAD-1 vs. CAD-2) for SD-CT and with 8 and 3 for ULD-CT. After separate statistical analysis of nodules with diameters of 5 mm and greater, the detection rates increased to 83 % and 61 % for SD-CT and to 89 % and 67 % for ULD-CT (CAD-1 vs. CAD-2). For both CAD systems there were no significant differences between the detection rates for standard and ultra-low-dose data sets (p > 0.05).
Dose reduction of the underlying CT scan did not significantly influence nodule detection performance of the tested CAD systems.
通过比较两家制造商的计算机辅助肺结节检测系统（CAD）在超低剂量计算机断层扫描（ULD-CT）和标准剂量CT（SD-CT）上的各自CAD结果，评估剂量降低对其性能的影响。
回顾性选择26例患者（13例男性和13例女性，年龄31 - 74岁）的多层计算机断层扫描（MSCT）数据集进行CAD分析。CT检查的指征为已知原发性恶性肿瘤或疑似肺恶性肿瘤的分期。CT图像在管电压120 kV（层厚1 mm）下分别以5 mAs（ULD-CT）和75 mAs（SD-CT）连续采集。参考标准由三位经验丰富的阅片者共同确定。将CAD阅读算法（预商用CAD系统，荷兰飞利浦：CAD-1；德国西门子LungCARE：CAD-2）应用于CT数据集。
共同阅片在SD-CT和ULD-CT上共识别出253个结节。结节直径在2至41 mm之间（平均直径4.8 mm）。SD-CT的检测率分别为72%和62%（CAD-1对CAD-2），ULD-CT的检测率分别为73%和56%。计算出每位患者的中位假阳性率，SD-CT分别为6和5（CAD-1对CAD-2），ULD-CT分别为8和3。在对直径5 mm及以上的结节进行单独统计分析后，SD-CT的检测率分别提高到83%和61%，ULD-CT的检测率分别提高到89%和67%（CAD-1对CAD-2）。对于两种CAD系统，标准剂量和超低剂量数据集的检测率之间均无显著差异（p > 0.05）。
基础CT扫描的剂量降低对所测试的CAD系统的结节检测性能没有显著影响。
