能谱CT铁-水基图定量含铁物质铁含量的准确性

目的 观察能谱CT铁-水基图定量含铁物质铁含量的准确性。方法 以蔗糖铁注射液及蒸馏水配制含铁浓度分别为20、10、5、2.5、1.25及0 mg/ml的铁-水溶液，另配置铁浓度分别为12、6、3、1.5、0.75及0 mg/ml的铁-碘混合液，置于5 ml PVC试管中。分别以管电流200、240及320 mA对不同铁浓度铁-水溶液及铁-碘混合液行能谱CT扫描，获得铁-水基图及铁-碘基图；比较各电流条件下铁-水基图中铁-水溶液的虚拟铁浓度(VIC)及VIC校正值的差异，以及铁-碘基图中铁-碘混合液VIC校正值的差异，分析铁-水基图中铁-水溶液VIC值及VIC校正值与铁浓度的相关性，拟合其回归方程。结果 管电流为200、240及320 mA时，铁-水基图中的铁-水溶液VIC(F=0.483，P=0.627)及VIC校正值(F=0.001，P=0.999)差异均无统计学意义，其VIC与铁浓度均呈线性相关(r=0.998、0.999、0.998，P均<0.001)，拟合回归方程(Y为VIC，X为铁浓度)分别为Y=0.615+1.050×X、Y=－1.149+1.027×X、Y=－0.129+1.037×X；VIC校正值与铁浓度亦均具有正相关性(r均=0.998，P均<0.001)，回归方程(Y为VIC校正值，X为铁浓度)分别为Y=－0.185+1.054×X、Y=0.221+1.022×X、Y=－0.009+1.037×X。管电流为200、240及320 mA时，铁-碘基图中的铁-碘混合液的VIC校正值差异无统计学意义(F=0.033，P=0.968)，其VIC校正值与铁浓度均呈正相关(r=0.986、0.983、0.988，P=0.002、0.003、0.002)。结论 能谱CT铁-水基图可准确定量含铁物质铁含量。

Accuracy of energy spectrum CT iron-water map for quantitative measuring iron content of iron-containing substances

Objective To observe the accuracy of energy spectrum CT iron-water map for quantitative measuring iron content of iron-containing substances. Methods Iron sucrose injection and distilled water were used to prepare iron-aqueous solutions with iron concentrations of 20, 10, 5, 2.5, 1.25 and 0 mg/ml, respectively. In addition, iron-iodine mixed solutions with iron concentrations of 12, 6, 3, 1.5, 0.75 and 0 mg/ml were prepared, respectively. All the solutions were placed in 5 ml PVC tubes, respectively. Energy spectrum CT scanning was performed on PVC tubes with different concentrations of iron at tube currents of 200, 240 and 320 mA to obtain iron-water and iron-iodine maps. The virtual iron concentration (VIC) and VIC correction values of iron-aqueous solutions in iron-water maps under different tube current condition, as well as the VIC correction values of iron-iodine mixed solutions in iron-iodine maps under different tube current conditions were compared, and the relationships of VIC and VIC correction values of iron-aqueous solutions in iron-water maps with iron concentration were analyzed, finally the regression equations were fitted. Results No statistical significance of VIC (F=0.483, P=0.627) nor VIC correction values (F=0.001, P=0.999) was detected among tube current of 200, 240 and 320 mA. There were linear correlations between VIC and iron concentration (r=0.998, 0.999, 0.998, all P<0.001), and the fitting regression equations (Y=VIC, X=iron concentration) were as follows, respectively:Y=0.615+1.050×X, Y=-1.149+1.027×X, Y=-0.129+1.037×X. VIC correction values were also positively correlated with iron concentrations (all r=0.998, all P<0.001), and the regression equations (Y=VIC correction values, X=iron concentration) were as follows, respectively:Y=-0.185+1.054×X, Y=0.221+1.022×X, Y=-0.009+1.037×X. No significant difference of VIC correction values of iron-iodine mixture in the iron-iodide maps among different tube currents (F=0.033, P=0.968), while the VIC correction values were positively correlated with iron concentrations (r=0.986, 0.983, 0.988, P=0.002, 0.003, 0.002). Conclusion Energy spectrum CT iron-water map could accurately quantify iron concentration of iron-containing substances.