Carbon dioxide angiography
Carbon dioxide is an excellent low-density contrast material which has been used for a variety of vascular interventions since the introduction of digital subtraction angiography. Due to high solubility rate and rapid diffusibility via lung CO2 is safe for intravascular usage.
Physical and chemical properties
CO2 is inexpensive, highly compressible, low viscous, and nontoxic gas. It does not mix with blood and hence cannot be diluted, rather it pushes away blood column within the vascular bed. Its extreme buoyancy helps to opacify non-dependant vascular bed and its very low viscosity allowing injection via small (22G) needles or 3F catheters even when with a guidewire in place. Its low viscosity results in filling of smallest branches regardless of blood flow rate and degree of stenosis.
- allergy to iodinated contrast material
- poor renal function
- superior in:
- detection of bleeding
- opacification of small collaterals in occlusive disease
- AV shunting in tumours
- CO2 has potential neurotoxic and cardiotoxic effects hence it should not be used for cerebral or coronary artery (above diaphragm aorta) angiograms.
- prone position injection should be avoided due to possible spinal ischemia
- arterial limb of dialysis AVF
- COPD patients
- in conjunction with nitrate oxide- marked increase in volume
- 1. Kyung Cho, Irvin F. Hawkins. Carbon Dioxide Angiography. ISBN: 9781420016260