Abstract: Objective　To investigate the differences of vascular enhancement and image quality between low-kiloelectron volt monochromatic images and low-tube-voltage images at indirect CT venography（ICTV） with dual-source dual-energy CT.Methods　In this retrospective study，50 consecutive patients suspected to have pulmonary thromboembolism（PTE） underwent multislice spiral CT pulmonary arteriography（CTPA） and ICTV by a dual-source dual-energy CT at Tongde Hospital of Zhejiang Province.Two radiologists evaluated 50 kiloelectron volt（keV） monochromatic images（group A） and 80 kVp images（group B） for vessel enhancement，image quality，image noise in the distal inferior vena cava（IVC），right femoral vein（at the level of the inguinal ligament），and right popliteal vein（in the popliteal fossa）．Results　Of the 50 patients，11 were found with venous thromboembolism，and 9 of them had PTE（including 3 also had DVT），2 had isolated DVT.Mean intravascular CT attenuation within the deep vein was significantly higher in group A than in group B（P<0.05）．Although the images of group A had significantly higher image noise than that of group B（P<0.05），there were no significant differences in image quality between the two groups（P>0.05）．Conclusion　Similar image quality with substantially higher venous attenuation was provided by 50 keV monochromatic images from dual-energy CT venography acquisition compared with 80 kVp images.

Key words: Phlebography；Tomography, X-ray computed；Radiography, dual-energy scanned projection

摘要： 目的　在双源CT双能量扫描模式下，对比分析间接CT静脉造影（ICTV）检查中低能量成像技术与低千伏成像技术的血管强化及图像质量差异。方法　连续选取2012年6月—2017年6月浙江省立同德医院收治的50例疑有肺血栓栓塞症（PTE）且 行双源CT双能量多层螺旋CT肺动脉造影（CTPA）联合ICTV检查的患者，获取下肢深静脉50 keV单能量图像（A组）及80 kVp图像（B组），分别测量下腔静脉远端、右股静脉（腹股沟韧带水平）、右腘静脉（腘窝水平）血管CT值及图像噪声，评估主观图像质量。结果　50例患者中，11例检出静脉血栓栓塞症（VTE）。其中9例检出PTE〔3例合并下肢深静脉血栓（DVT）〕，2例检出孤立性DVT。A组静脉CT值高于B组，A组图像噪声大于B组（P<0.05）。A组与B组主观图像质量评分比较，差异无统计学意义（P>0.05）。结论　双源CT双能量扫描模式下ICTV检查中，与低千伏（80 kVp）成像技术图像相比，低能量（50 keV）图像质量与之相仿，血管强化值更高。

关键词: 静脉造影术, 体层摄影术, X线计算机, 放射摄影术, 双能扫描投影