This is a clinical trial to test the clinical feasibility and safety of a novel CMR protocol. It aims to investigate a new Cardiovascular Magnetic Resonance (CMR) technique, called oxygenation-sensitive CMR (OS-CMR).~OS-CMR is a T2*-sensitive CMR sequence based on the so-called blood-oxygen-level-dependent (BOLD) effect. Because de-oxygenated hemoglobin acts as an endogenous paramagnetic contrast agent, the signal intensity (SI) in OS-CMR images is linearly correlated with hemoglobin oxygenation in the tissue. An increase in deoxyhemoglobin results in an drop in SI in OS-CMR images, while an increase in tissue oxygenation results in an increase in SI.~Therefore, OS-CMR has been found capable of assessing myocardial oxygenation and is being increasingly used to identify the vascular response of the coronary circulation to different stimuli.~Very recently, OS-CMR was used to identify the coronary vascular response to specific breathing maneuvers. Specifically, a marked increase of myocardial oxygenation was observed during a long breath-hold following a 60s period of hyperventilation. The combination of these two maneuvers appear to induce consistent and detectable changes of myocardial oxygenation, based on CO2-mediated coronary vasoconstriction and vasodilation, while being well tolerated by participants.~In this study, the investigators will use breathing maneuvers as coronary vasoactive stimuli to assess the myocardial oxygenation changes induced by such maneuvers with OS-CMR.~The investigators aim to assess if the breathing-induced relative increase of myocardial oxygenation (Breathing-induced Myocardial Oxygenation REserve, B-MORE) in a coronary territory is clinically feasible to serve as a marker for the severity of coronary artery stenosis.~Moreover, the investigators will assess the feasibility and safety of OS-CMR with breathing maneuvers in patients with suspected coronary artery disease in a multi-center setting.
This is a clinical trial to test the clinical feasibility and safety of a novel CMR protocol, combined with a specific breathing maneuver to identify myocardial regions exposed to severe coronary artery stenosis.