Carbon Dioxide Angiography

Carbon Dioxide Angiography: Scientific Principles and Practice

Kyung Jae Cho

Department of Radiology, Frankel Cardiovascular Center, University of Michigan Health System, University of Michigan Medical School, Ann Arbor, MI, USA. Vascular Specialist International. Vol. 31, No. 3, September 2015

"The use of carbon dioxide (CO2) as a contrast agent goes back to 1920s when the gas was used to visualize retroperitoneal structures. In the 1950s and early 1960s, CO2 was injected intravenously to delineate the right atrium

for the detection of pericardial effusion. This imaging technique developed from animal and clinical studies which

demonstrated that CO2 was safe and well tolerated with venous injections"

"CO2 is 28 times more soluble than oxygen and 54 times O2 more soluble than nitrogen. This high solubility of CO2 allows its injection into the arteries below the diaphragm and veins without clinically significant gas embolism. The solubility of CO2 and air can be assessed by DSA or fluoroscopy of the gas trapped in the right atrium in the left lateral decubitus position (right-side up position). Five mL of CO2 trapped in the right atrium will dissolve within 45 seconds. Larger volumes of CO2 will take a longer time to dissolve."

"The main benefit of CO2 as a contrast agent is the lack of renal toxicity and anaphylactic response. Therefore, it is the preferred alternative contrast agent in patients with renal failure and contrast allergy. Since CO2 is eliminated by the lungs in a single pass, unlimited volumes of CO2 can be used but injections should be separated by 2 to 3 minutes."

"The other important advantage of using CO2 is that it is a safe and effective flushing medium for the catheter and sheath. Because CO2 is immiscible with blood, it can prevent clots developing in the catheter."