Fine-needle percutaneous transhepatic parenchymal portal venography by using carbon dioxide: a pilot study in pigs

Our purpose was to evaluate the feasibility and safety of carbon dioxide (CO(2)) in fine-needle percutaneous transhepatic parenchymal portal venography and its potential clinical applications. Three Belgian landrace pigs received fine-needle percutaneous transhepatic parenchymal portal venography by using CO(2) as a contrast agent. Under fluoroscopic and B-mode ultrasonic guidance, right or left lobe of liver was punctured with a 22-G Chiba needle, through which CO(2) was injected with a dedicated CO(2) injector at injection rate of 20 ml/s for 20 ml, 40 ml/s for 40 ml, 40 ml/s for 60 ml, and 40 ml/s for 80 ml, respectively. The portal venograms were obtained by use of digital subtraction angiography (DSA) system with animal in supine position. In one pig transarterial portal venography was performed, in addition, using iodinated contrast agent. The portal vein was visualized in each run of venography. Optimal images of portal tree structure up to four-order branches were obtained in all those with CO(2) injection rate of 40 ml/s, which appeared much better in quality than those obtained by cranial mesenteric arteriography with iodinated contrast agent. No extravasation of CO(2), liver laceration, or any other complication occurred during the procedures. The technique we proposed demonstrated optimal portography, which appeared to be safe, minimally invasive, less time-consuming, cost-effective, and easy to perform, with great potential in clinical applications.