Movement compensation during carbon dioxide coronary angiography: In-vitro validation

The aim of this in vitro study was to evaluate the feasibility of movement compensation for CO2 coronary angiography. The use of CO2 as a contrast medium for coronary angiography in a routine clinical setting is still premature. Nonetheless, the gas can solve most of the problems related to iodine contrast-induced nephropathy and can be safely used for patients with renal insufficiency. In a previous work [I. Corazza et al., AIP Adv. 8(1), 015225 (2018)], we demonstrated that an adequate setting of the CO2 injection parameters (pressures and volumes) allows gas injection into the coronaries, avoiding reflux into the aorta and cerebral circulation. A mechanical mock simulating coronary circulation and movement was used to simulate different CO2 injection conditions. Simultaneous acquisition of ECG and optical images allowed synchronous frame extraction for post-processing analysis, like masking and stacking processes. A single test with a radiological apparatus was done to demonstrate the feasibility of the technique. By injecting CO2 at a pressure between the dicrotic notch and diastolic value, no reflux into the aorta was observed and the new software yielded final optical images of clinical quality after about 8 seconds of injection. The feasibility test under the X-ray apparatus gave promising results. CO2 coronary angiography is still far from becoming a clinical standard, but our bench evaluation demonstrates that if the injection parameters are well-controlled and physiological values known, CO2 can be used as a contrast agent not only for the lower part of the body, but also for the coronary arteries, respecting basic safety standards.