16层螺旋CT对肺动脉栓塞及下肢静脉血栓行联合成像的技术优势

目的探讨16层螺旋CT同时扫描肺动脉和下肢静脉的联合成像技术。方法40例疑为肺动脉栓塞(简称肺栓塞)的病人于16层螺旋CT上行肺动脉和下肢静脉联合成像。CT后处理包括最大密度投影(MIP)、多平面重建(MPR)及容积再现(VR)。采用t检验进行统计学分析。结果肺栓塞、下肢静脉血栓同时存在者25例，单纯下肢静脉血栓者8例，单纯肺栓塞者2例，二者均正常者5例。不同重建层厚均可清晰显示肺动脉栓子。肺动脉、下肢静脉增强后的CT值显著高于栓子的CT值。MPR、MIP、VR三者对肺栓塞的显示率分别为100％、100％、65％，下肢静脉血栓的显示率分别为100％、60％、50％。结论16层螺旋CT联合肺动脉、下肢静脉成像将为肺栓塞的诊断提供新的方法。

The technique advantages of 16-detector multi-slice spiral CT in evaluating combined pulmonary and deep vein thromboembolism

Objective To study the scanning technique of 16-detector multic-slice spiral CT (MSCT) for combined pulmonary artery and deep vein of lower limb in pulmonary thromboembolism (PE) patients.Methods Forty suspected pulmonary thromboembolism patients were performed both pulmonary artery angiography (CTA) and indirect deep vein venography (CTV) on 16-detector MSCT. The parameters of the latter as following :total contrast volume 120-150 ml, injection rate 4.0-4.5 ml/s (from antecubital vein), delay time 4.0 for CTA 20-23 s, CTV 120-180 s, collimation for CTA 1.25 mm and 0.625 mm, CTV 2.5 mm, scan range of CTV: from popliteal vein to the level of bilateral renal vein into the inferior vena cava. Postprocessing include MPR, MIP, and VR. The test was used to analyzed the images.Results Twenty five patients had both pulmonary thromboembolism(PE) and deep vein thromboembolism (DVT), 8 patients had only DVT, 2 had only PE, and 5 had neither. There was no difference between different collimation in depicting thrombus. The CT value number of enhanced pulmonary artery and lower deep vein was obviously higher than the thrombus. The value of MPR, MIP, VR for PE was 100%, 100%, and 65%, The value of MPR,MIP,VR for DVT is 100%, 60%, and 50%.Conclusion The technique of combined pulmonary CTA and deep vein CTV of 16-detector MSCT will provide a new modality for pulmonary thromboembolism patients.