双能CT区分两种造影剂的研究

Differentiation of Two Contrast Media Using Dual-energy CT

目的探讨双能CT扫描区分铋造影剂和钆造影剂的可行性。资料与方法将两组不同比例的铋造影剂和钆造影剂混合物置于试管内,第一组为碘海醇注射液和钆特酸葡胺注射液,体积比分别为0∶1、1∶6、1∶1、6∶1、1∶0;第二组为碘海醇注射液和果胶胶体铋溶液,质量浓度分别为0∶1、1∶6、1∶1、6∶1、1∶0。使用双能CT扫描后,以80 keV进行单能量图像重建,应用Liver VNC软件将双能数据进行虚拟平扫及碘含量分析。结果在80 keV虚拟单能量成像的条件下,第一组混合液的CT值为379~383 HU,第二组混合液的CT值为170~173 HU,且两组实际碘浓度与测量碘浓度之间差异均无统计学意义（P〉0.05）。物质分离图像中,碘造影剂和钆造影剂区分不明显,碘和铋造影剂区分明显。结论双能CT可以区分铋和钆这两种衰减率不同的造影剂,原子序数相差越大,区分效果越明显。

Purpose To evaluate the feasibility of using dual-energy CT scanner to differentiate two contrast media bismuth and gadolinium. Materials and Methods Two phantoms containing contrast media of different ratio were scanned on dual-energy CT. Group 1 was mixture of iodine and gadolinium solution with volume ratio of 0 ： 1, 1 ： 6, 1 ： 1, 6 ： 1 and 1 ： 0. Group 2 was mixture of iodine and bismuth solution with mass ratio of 0： 1,1 ： 6, 1 ： 1, 6 ： 1, 1 ： 0. Monoenergetic image reconstruction was performed at 80 keV. Liver VNC software was used for virtual scanning and iodine concentration analysis. Results Under 80 keV reconstruction, the measured CT attenuation of Group 1 was 379- 383 HU, and 170-173 HU in group 2. The iodine concentration of two groups was not significantly different between the calculated and actual iodine concentration （P〉0.05）. The dual-energy CT can distinguish two contrast media. Iodine and gadolinium contrast media were not statistically different, while iodine and bismuth contrast media agent could be easily differentiated. Conclusion Dual-energy CT can distinguish two contrast media with different attenuation.