[CO2 angiography: studies of gas filling of vessels and assessing the factors of influence on the injection process with a cardiovascular model].

Following the advent of digital subtraction angiography (DSA), carbon dioxide gas has become a useful contrast agent for arterial angiography. Former manual injection methods had precluded accurate dosing and reproducibility. An original gas injector was therefore developed and tested in a circulatory system model. This permitted an accurate evaluation of vascular gas-filling. it also proved possible to measure the injection parameters taking different influencing factors into account. It was shown that vessels up to 10 mm in diameter are virtually completely filled with gas. In vessels larger than 10 mm in diameter, a residual fluid level remains, which in turn reduces the possibility for complete vessel imaging. The injection flow is dependent primarily on the vascular circulation rate, vessel diameter and the inclination of the vessel. With respect to other factors examined, neither catheter size, number of holes nor the direction of the injection have any relevant influence.