The Earlier Research Of Postcaval Direct Venography With Multi-slice Spiral CT

Objective: To investigate the method of postcaval direct venography with Multi-slice spiral CT.Materials and Methods: 50 patients underwent postcaval direct venography (injected constrast medium through one or both lower extremities veins) with a Lightspeed 16 scanner or Lightspeed 64 scanner (GE, U.S.A), and compared with 10 patients who underwent indirect method (injected contrast medium through Veins of upper extremity). The Z scanning span was from the crista iliaca to about 2cm above diaphragm(reaching right atrium). Nonionic contrast (Ultravist 300, 100ml or 160ml diluted agents, 25%,50% ,75%level)was injected at speed of 1.5,2.5,3.5ml/s respectively via one or both lower extremities veins. Time delayed: Began scanning when 80% agents was injected. 0.5-0.6s /rotation, 5.0mm thickness, FOV 500mm. 120-140Kv, 300-400mA. Patients must hold their breath when scanning. The raw data of MSCTA were reconstructed with maximum intensity projection (MIP), volume rendering (VR), multiplannar reconstruction(MPR) and curved plannar reconstruction(CPR) techniques. Two radiologists independently evaluate the results of the two different methods.Results: In the 60 cases, when injected agents through both lower extremities veins, strethened with abdominal-belt, 25% level, injecting speed 1.5ml/s, volume 160ml, Time delayed when 80% agents was injected, the reconstructed imaging was best, and obviously better than the imaging of indirect method.Conclusion: Direct venography with multi-detector spiral CT is better than indirect method in showing inferior caval vein. Postcaval direct venography is an important method in detecting inferior caval vein diseases.