Cone Beam CT Indirect Portal Vein Angiography X-ray Exposure Time Delay Parameters Optimization

Objective: During indirect portal phlebography under cone beam CT, we chose different X-ray exposure delay value, and make a statistical analysis of the manifestation result of main branch and the 2°to 3° sub-branches of portal vein, and the active blood flow changes to figure out the optimal time window of manifesting multiple degrees of portal vein. Furthermore, we analyze the relationship between stage of liver cancer and the portal vein flow changes to optimize the treatment via liver artery occlusion.Methods: 120 cases of liver cancer patients during June 2013 to December 2014 was selected(all the patient was clinically diagnosed as primary liver cancer or liver metastatic cancer), and randomly assigned into groups A, B, C and D. Each group contains 30 cases. In each group a specific exposure delay value was set as listed: group A=12s, group B=14s, group C=16s, group D=18s. Contrast enhancement auto injector was set a delay of 1.1s. 20-30 m L iodixanol-320 was injected as the radiographic contrast medium, with an infusion rate of 4-5m L/s. For each group, we selected the 8s- Digital radiography(DR) scan, and the data gathering was finished on Syngo Workplace workstation by multiple plate reconstruction(MPR), which shows the blood flow of main branch and the 2°-3° sub-braches of portal vein. We observed the manifestation result of main branch and the 2°-3° sub-braches of portal vein in liver cancer patient in different exposure delays. All the data gathered was analyzed by chi-square difference testing in SPSS 12.0.Results: group A: exposure delay=12s,manifested portal vein(cases):18, manifested 2°-3°sub-branches of vein(cases):7, no 4°-5°sub-branches of vein shown; group B: exposure delay=14s, manifested portal vein(cases):23, manifested 2°-3°sub-branches of vein(cases):12, no 4°-5°sub-branches of vein shown; group C: exposure delay=16s, manifested portal vein(cases):29, manifested 2°-3°sub-branches of vein(cases):22, 4°-5°sub-branches of vein partly shown; group D: exposure delay=18s, manifested portal vein(cases):24, manifested 2°-3°sub-branches of vein(cases):24, 4°-5°sub-branches of vein partly shown. For each group, it shows a significant difference(P<0.05) between various exposure delay and the manifestation result of portal vein and its sub-branches. The prognosis of treatment guided by imaging result greatly increases.Conclusions: In cone beam CT indirect portal phlebography, there is a significant difference(P<0.05) between various X-ray exposure delay and the manifestation result of portal vein and its sub-branches. Therefore, cone beam CT indirect portal phlebography can correctly shows the relationship between stage of liver cancer and the portal vein flow changes, and can be administered clinically for treatment via artery occlusion and infusion.