螺旋CT肺结节检出率的实验研究

目的 通过对肺结节模型进行螺旋CT扫描，分析影响螺旋CT肺结节检出率的因素。方法用包绕水囊的绷带卷模拟肺及胸廓，面粉、黄油及固体石蜡按一定比例制作成CT值-10～50Hu的结节，直径为10mm和50Hm。分别采用螺距1，1．5，2进行扫描。模型扫描图像与正常成人胸部图像融合，由三名医师在不知模型结节的情况下分别读片，统计肺内结节的检出率和假阳性率。分析扫描螺距、结节的位置、与血管的关系等对其检出率的影响。结果 肺内10mm及5nm结节的检出率分别为100％，89．6％，增加螺距导致5mm的结节检出率下降。结节的检出率与其离血管的远近有关。结论 增大螺距导致肺内直径5mm结节的检出率下降。肺内结节与血管的关系影响其检出率。

Lung Nodules Detection with Spiral CT:Experimental Study

Objective To investigate the factors that affect the detection rate by scanning a lung nodule model.Methods The lung and the thoracic cage were simulated with a roll bandage surrounded by a cyst filled with water.Flour,butter and paraffin wax were mixed together in a certain ratio to simulate lung nodules 10mm and 5mm in diameter that CT values ranging from -10 to 50Hu.Spiral CT scans were performed at different pitch (1,1.5,2).The images of the simulated nodules were combined with the CT images of a normal adult's lung.Three radiologists interpreted the images and the number of the nodules they detected including both the real ones and the false-positive ones were calculated to investigate weather there was any difference between different pitch group and different locations.Results The detection rate of the 10mm and 5mm nodules were 100% and 89.6% respectively.The detection rate of the 5mm nodules declined when large pitch was used.Conclusion The detection rate was affected by the pitch,nodule locations and the relation between the nodules and lung vessels.