瞬时管电压切换单源双能CT定量评估肝脏铁含量的研究

Liver Iron Overload Quantitative Assessment by Fast-Kilovolt-Peak Switching Dual-Energy CT

目的探讨瞬时管电压切换单源双能CT物质分离技术定量测定肝脏铁沉积的可行性,且不同的扫描条件对测量结果是否有影响。方法10只实验兔分别肌肉注射不同剂量浓度的右旋糖酐铁建立铁过载模型。采用美国GE Revolution 256CT扫描仪器,选择能谱成像模式,管电压80/140 kVp瞬时切换,管电流分别为200 mA,240 mA,320 mA。将扫描图像传到后处理工作站重组铁(水)基物质对图像,测量虚拟铁浓度(VIC)。所有实验兔模型完成双能CT扫描后立即处死,获取肝标本经匀浆后用紫外分光光度计测定肝铁浓度,并将一部分肝组织进行普鲁士蓝染色分析。对三组管电流(200 mA,240 mA,320 mA)下相应的VIC与肝实际铁浓度(LIC)的相关性进行Spearmen分析,并拟合线性方程;经Kruskal-Wallis秩和检验分析三组不同管电流的VIC之间是否有差异性。结果经紫外分光光度计测得LIC的范围为0.12~2.81 mgFe/g湿重,不同管电流下的VIC与LIC均呈高度正线性相关(r^(2)值分别为0.974,0.962,0.941,P<0.05);Kruskal-Wallis秩和检验分析得χ^(2)=0.844,P=0.656。普鲁士蓝染色分析得出,随着注射右旋糖酐铁剂量增高,铁在肝内沉积越多,分布越广泛。结论瞬时管电压切换单源双能CT的VIC值可用于定量评估肝脏铁含量,且不同的管电流对虚拟铁含量测定的结果无明显差异。

objective To explore the feasibility of liver iron deposition quantification by using fast-kilovolt-peak switching dual-energy CT and explore whether different scaning conditions have an impact on the measurement results.Methods The iron overload model was established by intramuscular injection of different doses of iron dextran in 10 experimental rabbits.All rabbits were scanned by GE Revolution CT 256 slices scanner in GSI mode with rapid tube voltage switching between 80 and 140 kVp and with tube current 200 mA,240 mA,320 mA respectively.On post-processing workstation,all images of iron(water)-based substance pair were reconstructed and the virtual iron concentration(VIC)value were recorded.After examination the rabbits were sacrificed,assessments of liver iron concentration(LIC)were measured with UV spectrophotometer and a portion of liver speciments were analyzed by Prussian blue staining.The correlation between VIC and the actual liver concentration(LIC)of the three sets of tube currents(200 mA,240 mA,320 mA)was analyzed by Spearman correlation analysis and linear regression.In addition,VIC of the three sets of tube currents was compared with the Kruskal-Wallis rank sum test.Results The range of LIC measured by UV spectrophotometer is 0.12-2.81 mgFe/g wet weight.VIC was highly positively correlated with LIC under different tube currents(r^(2)value was 0.974,0.962,0.941,respectively P<0.05).Kruskal-Wallis rank sum testχ^(2)=0.844,P=0.656>0.05.Prussian blue staining showed that with the increase of iron injection of dextran,the more iron was deposited in the liver and distributed more widely.Coclusion VIC value of the fast-kilovolt-peak switching dual-energy CT can be used to accurately quantify liver iron accumulation and there is no significant difference between different tube currents.