瞬时kVp切换单源双能CT物质分离技术定量反映肝脏铁沉积的体模研究  

Quantification of the liver-iron concentration using fast-kilovolt-peak switching dual-energy X-ray CT combined with material decomposition method:a vitro experimental study

作　　者：谢婷婷[1] 刘龙平 单慧明[1] 石桥[1] 胡小红[1] 成官迅[1] 郭英 XIE Ting-ting;LIU Long-ping;SHAN Hui-ming

机构地区：[1]北京大学深圳医院医学影像中心,广东518036 [2]深圳市儿童医院放射科,广东518036 [3]GE中国CT影像研究中心,广州510623

出　　处：《放射学实践》2018年第12期1229-1233,共5页Radiologic Practice

基　　金：国家科技支撑项目(2013BAI07B100);深圳市科技计划项目(JYCJ20150403091443313)

摘　　要：目的:探讨瞬时kVp切换单源双能CT扫描结合物质分离技术定量评估肝脏铁沉积的可行性。方法:使用256排单源双能CT的GSI模式和管电压80/140kVp瞬时切换技术,管电流分别取200、320和485mA,对肝脏铁沉积体模(共6个PVC管,其内为正常大鼠肝脏匀浆-右旋糖酐铁混合液,铁浓度分别为50.000、25.000、12.500、6.250、3.125和0mg/mL)进行扫描。随后使用GSI分析软件,获得铁/水基物质对图像,于每个PVC管内勾画直径6mm、面积为28.26mm2的圆形ROI,测量各ROI的虚拟铁浓度值(VIC),每个PVC管自上向下选取3个层面,取3个层面VIC测量值的平均值录入数据库。采用单因素方差分析比较3组管电流条件下VIC测量值的差异,再对VIC与实际肝脏铁浓度(LIC)的相关性行Pearson分析,并拟合线性方程。结果:不同管电流(200、320和485mA)条件下测量的VIC值均与LIC均呈高度正相关,相关系数(r)值均为0.998(P=0.000),且不同管电流下VIC值的差异无统计学意义(P=0.999,F=0.001),散点图显示VIC(x)与LIC(y)呈线性相关关系,拟合的线性方程分别为y=1.076x-1.602(R2=0.995,P=0.000,F=994.169),y=1.104x-1.193(R2=0.995,P=0.000,F=969.015)和y=1.089x-1.461(R2=0.996,P=0.000,F=1112.086)。结论:瞬时kVp切换单源双能CT物质分离技术可定量分析肝内铁沉积,从而为临床无创性分析铁沉积的严重程度及评估疗效提供重要信息。Objective:To evaluate the feasibility and accuracy of using fast-kilovolt-peak switching dual-energy CT combined with material decomposition method for quantification of liver iron content.Methods:Six homogeneous liver-iron mixed samples with iron concentration(LIC)of 50.000,25.000,12.500,6.250,3.125,1.563 and 0mg/mL were prepared.All samples were scanned at a dua-lenergy CT scanner using GSI mode,rapid tube voltage switching between 80 and 140kVp,and three groups of tube current(200,320 and 485mA respectively).Imaging data were processed with GSI imaging analysis software package(GSI Viewer)for material decomposition and characterization.Virtual Iron concentration(VIC)on iron-water bases images was measured with consistent regions of interest(ROIs)placed in the tube center with a diameter of 6 mm and area of 28.26mm 2.Each sample was measured at three different slices for average and statistical analysis.The difference of virtual iron concentration(VIC)among the three groups was analyzed by one-way ANOVA.A linear regression analysis was performed to analyze the relationship between VIC and the actual iron concentration(LIC).Results:There was no significant difference in VICs among the three groups using different tube current(P=0.999,F=0.001).The liver-iron model showed good linear relation between VIC and LIC under tube current of 200,320 and 485mA(all r=0.998,P=0.000),and the corresponding linear correlation equation under tube current of 200,320 and 485mA was y=1.076x-1.602(R 2=0.995,P=0.000,F=994.169),y=1.104x-1.193(R 2=0.995,P=0.000,F=969.015)and y=1.089x-1.461(R 2=0.996,P=0.000,F=1112.086),respectively.Conclusion:The fast-kilovolt-peak switching dual-energy CT and material decomposition techniques can be used for quantitative evaluation of different degrees of liver iron overlay,thus can provide important informations for clinical noninvasive assessment of iron deposition severity and therapeutic effect.

关 键 词：肝脏 铁过载 体层摄影术 X线计算机 双能CT 物质分离 

分 类 号：R814.42[医药卫生—影像医学与核医学] R575.5[医药卫生—放射医学]