宝石能谱CT在儿童脊柱侧弯术后CT影像中去除金属植入物伪影的应用  

The Value of Dual Energy Spectral CT in Reducing Metal Artifacts Caused By Metallic Implants After Scoliolosis Operation in Children

作　　者：霍爱华[1] 于彤[1] 孙记航[1] 胡迪[1] 林蕊[1] 彭芸[1] 

机构地区：[1]首都医科大学附属北京儿童医院影像中心,100045

出　　处：《临床放射学杂志》2013年第8期1180-1183,共4页Journal of Clinical Radiology

基　　金：首都医学发展基金项目(编号:2009-2077)

摘　　要：目的探讨宝石能谱CT在儿童脊柱侧弯术后CT影像中去除金属植入物伪影的临床价值。方法对8例行CT复查的脊柱侧弯术后患者行能谱CT扫描,采用GSI扫描模式,扫描后获得140 kVp混合能量图像(QC)及不同能量的单能量图像(MONO),同时使用单能金属伪影消除重建(MARs)技术对能谱数据进行去金属伪影获得图像(MONO+MARs,共3组)。8例共选取10个带有金属植入物的部位,再对每个部位选取2个伪影最大的层面(10个部位共计20层面)及1个伪影最小层面(作为背景)进行感兴趣区(ROI)客观噪声值(SD)的测定。每个层面选取2个ROI(椎管外软组织和椎管内软组织),由一位有经验的放射科医师独立评估图像质量并分别在工作站测量其SD值、计算伪影指数(AI)。对所获数据采用SPSS 13.0进行统计学处理。使用非参数Wilcoxon秩和检验法进行组间差异统计学分析。结果 MONO组和MONO+MARs组图像质量随着keV的升高明显改善。在120～140 keV水平可获得最小SD值及AI。对于椎管外组的SD值及AI值,MONO组SD值最低,QC组最高,两者之间差异有统计学意义(P<0.05),QC组及MONO+MARs组两者差异无统计学意义(P>0.05)。椎管内组的SD值及AI值,MONO+MARs组最低,QC组最高,两者之间差异有统计学意义(P<0.05),QC组与MONO组比较差异亦有统计学意义(P<0.05),MONO组与MONO+MARs组比较差异无统计学意义(P>0.05)。结论宝石能谱CT扫描及MARs后重建技术能显著改善儿童脊柱侧弯术后CT图像质量。对于椎管外软组织金属植入物伪影的去除,MONO组图像表现较突出;对于椎管内软组织的观察,MONO+MARs组及MONO组图像质量均好于QC组,其中MONO+MARs组图像质量略胜于MONO组。Objective To investigate the value of dual energy spectral CT in reducing metal artifacts caused by metallic implants after scoliolosis operation in children. Methods Eight patients after scoliolosis operation were examined with du- al energy spectral CT imaging mode. Three types of images were reconstructed： polychromatic 140 kVp （QC）, monochro- matic （MONO） images from 80 -140 keV and MONO with metal artifact reduction system （MONO ＋ MARs）. For eight patient, ten positions with metallic implants were selected, and for every position, two image slices with the highest metal ar- tifacts and one image slice with the least metal artifacts were selected. For every image slice, two regions of-interest （ROI） （on soft tissue inside and outside of vertebral canal） were selected. One experienced radiologists independently assessed image quality, measured standard deviations （SD） in ROI, and calculated artifact index （AI）. Image quality scores were analyzed by Wilcoxon Signed Rank test, and artifact indexes were analyzed by Student t test. Results Image quality im- proved as the energy level （keV） increased on the MONO and MONO ＋ MARs images. At about 120 - 140 keV, lowest SD and AI were obtained on MONO and MONO ＋ MARs images for areas outside and inside the vertebral canal, respectively. There was significant difference of SD and AI outside the vertebral canal between MONO images and QC images （ P 〈 0.05 ）. There was no significant difference of these values between MONO ＋ MARs images and QC images （ P 〉 0.05 ）.For the soft tissue inside vertebral canal, there were significant differences of SD and AI between MONO and QC images, and between MONO ＋ MARS and QC images （ all P 〈 0.05 ）. There was no significant difference between MONO and MONO ＋ MARs images （P 〉 0.05）. Conclusion The image quality in the area with metal implants after scoliolosis oper- ation was improved by monochromatic images with spectral CT imaging both inside and outside vertebral c

关 键 词：能谱成像 金属植入物 伪影 儿童 脊柱侧弯 

分 类 号：R816.92[医药卫生—放射医学]