肺结节螺旋CT检测的螺距效果

Very Effect on Detection of Pulmonary Nodule of Spiral CT Pitch

目的:比较螺旋CT在检测肺结节时增加螺距和常规螺距的不同效应。材料与方法:对100例转移癌肺结节患者以1.0螺距行胸部螺旋CT扫描:随机分别以1.2(n=33)、1.5(n=34)与2.0(n=33)的增加螺距在同样的扫描断面对患者行进一步扫描;配对分析结节的数量、大小和分布。结果:在以螺距1.5和2.0的扫描上发现漏检病变的倾向,但均无显著性差异;对于螺距1.2,1.5与2.0的相关系数分别为r=.982,k=.977与r=.989。螺距为2.0的扫描因其显示小的孤立性结节的清晰度很差而低估了病变分期。结论:增加螺距与否对扫描检出效果通常无大影响;但对于孤立性结节患者,增加螺距扫描会低估疾病。对于肺转移性疾病的最初分期,扫描螺距宜小于1.5。

Purpose：To compare spiral computed tomography（CT）performed at increased pitch with spiral CT perfomed at standard pitch in the detection of pulmornary nodules.Materials and Methods：Spiral CT scanning of the thorax was perfomed with a pitch of 1.0 in 100 patients with pulmonary nodules due to metastases.The patients were also randomly assigned to undergo further scanning with a pitch of 1.2（n=33）,1.5（n=34）,or2.0（n=33）at the same scanning session.The scan pairs were analysed for number,size,and distributiong of nodules.Results：A bias toward undercounting was noted on scans with a pitch of 1.5 and 2.0;respectively.significant.Correlation coeffecients were r=.982,r=.977,and r=.989 for scans of pitch 1.2,1.5,and 2.0,respectively.Diseases in one patient would have been prosepectively understged from findings on a scan of pitch 2.0 because of poor conspicuity of a small solitary nodul.Conclusion：Fingdings from scans with increased pitch generally agree well with those from scans with standard pitch,however,there is a greater risk of understanding of disease in patients with solitary nodules as pitch increases.Pitch should be limited to no greater than 1.5 for initial staging of pulmonary metastatic disease.