Objective To investigate the value of CARE Dose 4D technique in chest spiral CT scanning of physical examination population. Methods 100 cases (50 men and 50 women) undergone chest CT scanning for physical examination were randomly chosen as study group, another 100 cases (50 men and 50 women) were chosen as control group using Siemens Somatom Emotion Duo spiral CT and setting 80 mAs for quality reference value. CARE Dose 4D technique was used in study group, while control group was not. Effective mAs value and volume CT dose index (CTDIvol) automatically displayed in machine while scanning and actual mAs value of every image were recorded respectively. Image quality of two groups was classified in three level (excellent, good, poor) by two deputy chief physicians with double blind method. The consistency of subjective judgement of two deputy chief physicians was determined with Kappa statistics. The effective mAs and CTDIvol (mGy) of standard deviation (SD) and standard deviation (xzts) of two groups were respectively computed by SPSS11. 5 software, measurement data by T test and classification data by chi-square test (significance level P is 0. 05). Results When setting 80 for quality reference mAs, the average effective mAs value in study group decreased to 18 (22. 5%)than that in control group, the average CTDIvol value decreased to 1. 95 mGy (22. 75%) than that in control group,the difference between the two groups was statistical significance!t was respectively 13. 879,7. 677,P<0. 01). In subjective judgment of image, the fine rate in study group was 100% , which was higher than that in control group (98% ) ,and the image quality in two groups had not statistical significance by chi-square test (x2 =0. 49,P>0. 05). 52 cases in study group were found with lesions(52%). Conclusion Using CARE Dose 4D technique of chest CT scanning in physical examination population has remarkablely clinical significance.%目的 探讨多层螺旋CT CARE Dose 4D技术在体检人群胸部扫描中的应用价值和意义.方法 随机选取体检人群胸部CT扫描病例男、女各50例共100例作为实验组,回顾性选取已做胸部CT扫描的体检人群男、女各50例共100例作为对照组,使用Siemens Somatom Emotion Duo螺旋 CT机,设置质量参考mAs为80.实验组使用CARE Dose 4D技术,对照组不使用CARE Dose 4D技术.记录每位体检人员扫描时自动显示的有效mAs、容积CT剂量指数(CTDIvol)值和每幅图像上的mAs值.将2组病例的图像质量由2位副主任医师按优、良、差3级双盲法评判.用Kappa方法检验2位副主任医师主观评判结果间的一致性,使用SPSS11.5统计软件,分别计算出2组图像的有效mAs、CTDIvol(mGy)的均数和标准差(x±s),计量资料经t检验,分类资料进行卡方检验(检验水准P取0.05).结果 在设置质量参考mAs为80时,实验组平均有效mAs比对照组下降18(22.5%),平均CTDIvol值实验组比对照组下降1.95 mGy(22.57%),2组间差异具有显著统计学意义(t值分别为13.879、7.677,P<0.01).图像主观评判实验组优良率为100%,高于对照组(98%),2组图像质量经卡方检验无统计学差异(χ2=0.49,P>0.05).实验组100例CT图像发现病变52例(占52%).结论 体检人群胸部CT扫描使用CARE DOSE 4D技术,具有显著临床应用价值和意义.
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