CO2 digital subtraction splenoportography with the "skinny" needle: experimental study in a swine model

Carbon Dioxide Angiography: Scientific Principles and Practice

Carbon dioxide (CO₂) is a colorless, odorless gas which occurs naturally in the atmosphere and human body. With the advent of digital subtraction angiography, the gas has been used as a safe and useful alternative contrast agent in both arteriography and venography. Because of its lack of renal toxicity and allergic potential, CO₂ is a preferred contrast agent in patients with renal failure or contrast allergy, and particularly in patients who require large volumes of contrast medium for complex endovascular procedures. Understanding of the unique physical properties of CO₂ (high solubility, low viscosity, buoyancy, and compressibility) is essential in obtaining a successful CO₂ angiogram and in guiding endovascular intervention. Unlike iodinated contrast material, CO₂ displaces the blood and produces a negative contrast for digital subtraction imaging. Indications for use of CO₂ as a contrast agent include: aortography and runoff, detection of bleeding, renal transplant arteriography, portal vein visualization with wedged hepatic venous injection, venography, arterial and venous interventions, and endovascular aneurysm repair. CO₂ should not be used in the thoracic aorta, the coronary artery, and cerebral circulation. Exploitation of CO₂ properties, avoidance of air contamination and facile catheterization technique are important to the safe and effective performance of CO₂ angiography and CO₂-guided endovascular intervention.

CO2 Splenoportography for Evaluating the Splenic and Portal Veins before or after Liver Transplantation

The authors report their experience with CO(2) splenoportography in a retrospective review of 15 studies performed in 13 patients before or after liver transplantation. The studies were performed by injecting CO(2) through a small caliber needle introduced into the splenic parenchyma with ultrasound guidance and imaging with conventional digital subtraction techniques. The findings were compared with clinical follow-up and other imaging studies when available. Eight of the 15 studies were normal, of which two were confirmed by additional studies. Six of the 15 studies were abnormal, all of which were compared with additional studies. There was one nondiagnostic study and two false positives. There were no reported complications. The authors' experience suggests that CO(2) splenoportography is a minimally invasive method for safely and accurately evaluating the splenic and portal veins.