双能CT应用于分子影像学的可行性初探——模体实验  

Feasibility of fast kVp switching dual energy CT in molecular imaging:a preliminary study

作　　者：容蓉[1] 丁杰[2] 王霄英[1] 姜原[1] 蔡文超[1] 邱建星[1] 宋玉军[2] 

机构地区：[1]北京大学第一医院医学影像科,北京100034 [2]北京航空航天大学材料科学与工程学院,北京100191

出　　处：《放射学实践》2012年第7期713-717,共5页Radiologic Practice

摘　　要：目的:利用双能CT成像测定不同浓度的Fe3O4纳米颗粒溶液和银单质纳米颗粒溶液内的铁和银的含量,探讨双能CT成像对于铁、银纳米溶液定量分析的可行性,并与MRI扫描结果进行对照。方法:使用MRI T2*GRE序列对11个不同浓度的Fe3O4纳米颗粒溶液和13个不同浓度的银单质纳米颗粒溶液进行扫描;分别测出不同浓度Fe3O4纳米颗粒和银单质纳米颗粒溶液的相对信号强度,对相对信号强度和理论浓度进行Pearson相关分析,如果两者具有显著相关性,则进一步进行线性回归分析。使用双能CT(Discovery CT750HD)对以上不同浓度的Fe3O4纳米颗粒和银单质纳米颗粒溶液进行扫描,采用宝石能谱成像(GSI)模式,GSI图像基于铁/水对和碘/水对,选定3个层面分别测量溶液中的铁含量和银含量,并且测出不同浓度溶液的物质有效原子序数和混合能量图中的CT值,分别对实测浓度、有效原子序数、CT值与理论浓度进行Pearson相关分析,然后对与理论浓度具有显著相关性的指标进行线性回归分析。结果:Fe3O4纳米颗粒溶液的MRI相对信号强度与理论浓度有显著相关性(r=-0.940,P<0.01),一元线性回归线性关系好(R2=0.8836);银单质纳米溶液的相对信号强度和理论浓度无显著相关性(r=-0.226,P=0.457)。双能CT铁纳米溶液的实测浓度和理论浓度有相关性(r=0.682,P<0.05),一元线性回归分析两者线性关系中等(R2=0.4697);铁纳米溶液的有效原子序数与理论浓度无显著相关性(r=0.193,P=0.57),CT值与理论浓度也无显著相关性(r=-0.149,P=0.662);银纳米颗粒实测浓度与理论浓度有显著相关性(r=0.926,P<0.01),一元线性回归分析两者线性关系好(R2=0.8482),测量的有效原子序数与理论浓度也有显著相关性(r=0.934,P<0.01),一元线性回归分析两者线性关系好(R2=0.8643),CT值与理论浓度无显著相关性(r=0.064,P=0.835)。结论:对顺磁性较强的Fe3O4纳米颗粒溶液采用MRI磁敏感序Objective ： Using dual energy CT to measure the contents of iron and silver in Fe3O4 and single silver nano- particle solutions with different concentration and to investigate the feasibility of quantitative analysis of Fe3O4 and single silver nanoparticles by dual energy CT. The results were correlated with MRI findings. Methods： Eleven Fe3O4 nanoparticle solutions and thirteen silver nanoparticle solutions in different concentration were prepared and examined by using MRI T2 ＊ GRE sequence. Their relative signal intensities were measured. Pearson correlative analysis was calculated to find out the relative signal intensities with that of theoretical real concentration. If significant correlation was existed,further linear re- gression analysis would be made. Dual energy CT （Discovery CT750 HD） with gemstone spectral imaging （GSI） mode was also used to examine the above mentioned solutions. GSI based on iron/water and iodine/ water as control, 3 levels were chosen to measure iron and silver in these solutions. The effective Z-number and CT values of the mixed energy maps were measured. Pearson correlation analysis and linear regression of these CT value and real theoretical concentration were calcu- lated as well. Results：Relative signal intensity of Fe3 O4 nanoparticles in T2 ＊ GRE images had correlation with its real con centration （r= --0. 940, P=0.01）, and the linear regression was good （R2 = 0. 8836）. Relative signal intensity of single sil- ver nanoparticles in T2 ＊ GRE images had no correlation with its real concentration （rE --0. 226 ,P=0. 457）. The measured concentration of Fe3 04 nanoparticles solution by dual energy CT had correlation with that of real concentration （r=0. 682, P%0.05）, with moderate linear regression relation （R2 =0. 4697）. Effective Z-number of Fe3O4 nanoparticles had no signif- icant correlation with its real concentration （r= 0. 193, P= 0.57）, the CT values had no correlation with its real concentra- tion as well （r=-0. 149, P= 0. 662�

关 键 词：体层摄影术 x线计算机 能谱成像 磁共振成像 纳米颗粒 

分 类 号：R814.42[医药卫生—影像医学与核医学] R811.1[医药卫生—放射医学]