Computer Assisted Diagnosis System for CT Screening of Lung Cancer

在日本，1997年有45，000多人死于肺癌，肺癌是男性中最高的原因。近年来，多项研究报道了螺旋CT成像的可行性和有效性，认为它可能是一种有效的肺癌筛查方法。为了提高早期肺癌结节的检出率，我们开发了一个计算机辅助诊断系统。该CAD系统具有基于低剂量螺旋CT图像的候选结节的自动检测。CT筛查的双重阅读是减少漏诊结节数量的一种潜在解决方案。但实际上，这是不可行的。另一个潜在的解决方案是使用CAD系统作为第二阅读器。2000个连续CT图像（作为肺癌筛选的一部分）由胸部放射科医生和CAD系统进行测试。因此，CAD系统检测到许多候选结节，而放射科医生最初没有看到这些结节。放射科医师和CAD系统之间的双重阅读得到有效认证。CAD系统还具有基于高剂量螺旋CT图像的每个结节候选者的良性或恶性诊断。100个连续的CT图像，这是测量的检测候选结节的CT筛查，比较评价之间的放射科医生和CAD系统。CAD系统显示出80%的性能上级放射科医师的解释。CAD软件可以检测到肺结节，否则这些肺结节可能在最初的解释中被放射科医生忽略。如果发现检测到的结节处于肺癌的早期阶段，则这可以为患者提供实质性益处。

In Japan more than 45,000 people died of lung cancer in 1997 and the lung cancer was the highest cause among males. Recently, several studies have been reporting feasibility and efficacy of helical CT imaging that it may be an effective screening modality for lung cancer. In order to improve the chance of detecting pulmonary nodules which may be early lung cancers, we have been developping a computer-assisted diagnostic (CAD) system. This CAD system has an automatic detection of candidate nodules based on low dose helical CT images. Double reading of the CT screening is one potential solution to decreasing the number of the missed nodules. However, in practice, that is not feasible. Another potential solution is the use of the CAD system as the second reader. Two thousand consecutive CT images, which are obtained as part of lung cancer screeing, were tested to the thoracic radiologists and the CAD system. As a result, many candidate nodules were detected by the CAD system which were not seen initially by the radiologist. The double reading between the radiologist and the CAD system was effectively certified. The CAD system also has a benign or malignant diagnosis for each nodule candidate based on high dose helical CT images. A hundred of consecutive CT images, which are measured for the detection of candidate nodules on the CT screening, were comparatively evaluated between the radiologists and the CAD system. The CAD system showed an 80 % performance superior to the radiologist interpretation. The CAD software may detect pulmonary nodules which may have otherwise been overlooked by the radiologists at the initial interpretation. This may provide substantial benefit to the patient if the detected nodules are found to be at an early stage of lung cancer.