低kVp联合迭代重建在青年军人腰椎CT检查中的应用研究

摘要

Objective To evaluate the clinical value of low kVp with iterative reconstruction in multislice spiral computed tomography of lumber vertebrae in young soldiers. Methods Sixty young soldiers who suffered from lumbar diseases were randomly divided into a control group(120 kVp)and a test group(100 kVp),who underwent CT examination with 120 kVp tube voltage in the control group and 100 kVp tube voltage in the test group.The control group went through filtered back projection (FBP)for image reconstruction.The test group applied FBP or sinogram-affirmed iterative reconstruction(SAFIRE)based on image reconstruction requirements,and then were divided into FBP test group and SAFIRE test group.The noise and SNR (signal to noise ratio)of the images were measured in each group.Meanwhile two experienced radiologists evaluated the quality of images.CTDIvol,DLP and ED were used to measure the scan dose in each group.Mean tube current was recorded by CARE Dose 4D.The data were analyzed with SPSS.Results There were no significant difference between the objective and subjective image evaluations in SAFIRE test group and the control group (P>0.05),while there were statistical differences between FBP test group and the control group or between the two test groups(P<0.05).The radiation doses in the test groups were both lower significantly than that in the control group,and the ED values in the test groups were decreased by 43% when compared with the control group. The test groups had the tube voltages not obviously different from that in the control group (P>0.05). Conclusion The radiation dose in the lumbar multislice spiral CT examination of young soldiers is decreased significantly when the tube voltage falls to 100 kVp,the same image quality as that by conventional 120 kVp tube voltage can be obtained by combining iterative reconstruction.%目的:探讨腰椎CT低管电压(kVp)联合迭代重建技术在青年军人中的临床应用,以保证在图像质量不变的情况下降低辐射剂量.方法:将60例临床要求行腰椎CT扫描的青年军人随机分为对照组(120 kVp)和实验组(100 kVp),对照组图像重建方式为滤波反投影法(filtered back projection,FBP),实验组根据图像重建方式不同分为实验组+FBP以及实验组+正弦图确定迭代重建法(sinogram-affirmed iterative reconstruction,SAFIRE),划定感兴趣区测量噪声值及信噪比进行客观评价,同时进行图像质量主观评分;运用容积CT剂量指数(CT dose index volumes,CT-DIvol)、剂量长度乘积(dose length product,DLP)及有效辐射剂量(effective dose,ED)评估2组不同管电压的辐射剂量,并记录平均管电流,将各数据采用SPSS统计软件包进行统计学分析.结果:实验组+SAFIRE与对照组+FBP比较其图像主客观评价差异无统计学意义(P>0.05),而实验组+FBP与对照组+FBP以及实验组+SAFIRE与实验组+FBP比较差异均有统计学意义(P<0.05).实验组的辐射剂量均较对照组明显降低,其中ED下降约43%.2组间平均管电流比较差异无统计学意义(P>0.05).结论:在青年军人的腰椎多层螺旋CT检查中,将管电压降低至100 kVp时可明显降低辐射剂量,联合迭代重建技术后可获得与常规管电压(120 kVp)相同的图像质量.