Development of 4-dimentional image construction for sequential chest radiograph.

为了辅助放射科医生对胸部X线片的筛查诊断，开发了一种使用数字图像处理的时间减影技术。两个连续图像的精确图像配准使我们能够检测到它们之间的差异图像中的细微变化。在这项研究中，介绍了一种新的基于“肺标记”匹配的方法，从计算机X线摄影系统拍摄的病例中选择了29对有和没有时间变化的顺序后前位胸片。在以前和现在的X线片中，图像配准与“肺斑纹”的局部匹配被采用。8位放射科医师在有和没有显示“差异影像”的情况下进行了观察者表现测试。使用时间减影图像的观察者表现显示，8位观察者中有6位被诊断具有较高的敏感度(平均为43.9%到55.3%)和可比的假阳性反应。曲线下的平均面积也从0.596提高到0.647，具有统计学意义。采用这种配准技术的减影图像提高了对细微时间变化的诊断准确率。

To aid radiologists in the diagnosis of screening chest radiographs, a temporal subtraction technique using digital image processing was developed. The accurate image registration of two sequential images enables us to detect even subtle changes in the "difference image" between them. In this study, a new method based on matching "lung markings" is introduced.Twenty-nine pairs of sequential posteroanterior chest radiographs with and without the temporal changes were selected from cases taken with the computed radiography system. Image registration was employed with the local matching of "lung markings" in previous and current radiographs. Observer performance tests with and without indicating the "difference image" between them was carried out by eight radiologists.Observer performance with the temporal subtraction image shows that six of eight observers diagnosed with higher sensitivity (mean, 43.9% to 55.3%) and comparable false positive response. Mean area under the AFROC (Alternative Free-Response Receiver Operating Characteristics) curve also improved from 0.596 to 0.647 showing statistical significance.The subtraction image using this registration technique improves the diagnostic accuracy for subtle temporal changes.