多层螺旋CT直接下肢静脉造影初探

目的 讨论多层螺旋CT直接下肢静脉造影增强扫描的对比剂注射方式、浓度和延迟时间,寻求较为理想的CT直接下肢静脉造影方案.方法 选择下肢静脉疾病患者32例,采用不同对比剂浓度与不同注射速率进行CT直接下肢静脉造影检查,并对图像对比分析,22例与X线下肢静脉造影进行分节段静脉显示能力对比分析.结果 血流相关性伪影为影响CT下肢静脉造影图像质量的主要因素,注射速率1.5 ml/s和2.5 ml/s组的图像评级差异有统计学意义(χ~2=5.495,P=0.019),稀释浓度为25%与15%的图像评级差异无统计学意义(χ~2=3.333,P=0.068).CT下肢静脉造影与X线下肢静脉造影在胫前静脉、胫后静脉、腘静脉与股静脉显示能力相同(χ~2=2.095,P=0.148),CT下肢静脉造影显示髂静脉的能力优于X线下肢静脉造影(χ~2=8.324,P=0.004).结论 CT下肢静脉造影髂静脉优于X线下肢静脉造影;采用延迟50 s经足背静脉以2.5 ml/s速度注射45 mgI/ml浓度(非离子型300 mgI/ml对比剂稀释15%)可获得较满意的诊断图像.

Preliminary application of multi-slice CT direct venography in lower extremity vein

Objective To discuss the injective method, contrast agent concentration and delay time of MSCT direct venography in lower extremity vein, in order to make optimal venographic schedule. Methods Thirty-two patients with lower extremity vein diseases underwent MSCT direct venography in using different concentration and injective rate of contrast agent, and the images were analyzed. The displaying ability of MSCT direct venography in lower extremity vein segment was compared with that of X-ray venography in 22 patients. Results Blood flow correlation constructed defect was the main factor impacting image quality of CT venography in lower extremity. The image scores between the groups of injective rate 1.5 ml/s and the group of 2.5 ml/s were statistically different (χ~2=5.495, P=0.019), whereas no difference of image score was found between the group of concentration of 25% and 15% (χ~2=3.333, P=0.068). The displaying ability of CT and X-ray venography in anterior tibial vein, posterior tibial vein, popliteal vein and femoral vein was not statistically different (χ~2=2.095, P=0.148). For iliac vein, the displaying ability of CT outstripped that of X-ray venography (χ~2=8.324, P=0.004). Conclusion With the schedule of delay time 50 s, injective rate 2.5 ml/s and concentration 45 mgI/ml (nonionic 300 mgI/ml and diluted 15%), MSCT direct venography in lower extremity can acquire satisfactory image, and its displaying ability of iliac vein is better than that of X-ray venography.