肝脏多层螺旋CT血管成像的期相设置与优化

The phase setting and optimization of multislice CT on hepatic CT angiography

目的 探索多层螺旋CT在肝脏CT血管成像 (CTA)中的最佳期相设置条件。方法参照时间 密度曲线 ,选择门脉与肝实质密度差最大的时间段 (40s)进行门脉系统血管的检查 ,并同时行传统肝脏动脉期 (2 0s)与门脉期 (65s)检查。采用此期相设置对 2 0例志愿者进行肝脏CTA检查 ,并将 40s所得图像与 65s图像进行比较。结果 在注射对比剂后 40s门静脉血管与肝实质CT值差为 66 96HU ,而 65s时二者差值为 39 58HU。统计显示 40s时门静脉与肝实质密度差明显大于65s的图像 (F =7 91 2 ,P <0 .0 1 )。结论 门脉系统CTA以注射对比剂 40s较传统

Objective To seek for the best phase setting of multislice CT on hepatic CTA. Methods A new phase (40 s) protocol for liver CTA was proposed upon the most contrast difference between the portal vein and the liver parenchyma from the density time curves. 20 volunteers were examined with the proposed time phase (40 s), and with traditional arterial phase (20 s) and portal venous phase (65 s) as well. And the images acquired at 40 s and 65 s were compared. Results At 40 s and 65 s after the injection, the density differences between the portal vein and liver parenchyma were 66.96 HU and 39.58 HU, respectively. The statistical data showed that the 40 s time phase provided the best enhancement effect in reconstruction of the portal vein system compared with that of traditional portal venous phase (65 s) process ( F =7.912 0, P =0.007 7). Conclusion 40 s after contrast injection should be proposed as the time phase for the optimal reconstruction of the portal vein system in CTA.