Determinants of myocardial perfusion reserve measured from coronary sinus phase-contrast imaging during regadenoson stress CMR

Background Measurement of myocardial perfusion reserve (MPR) can potentially extend the scope of conventional myocardial perfusion imaging from detection of flow limiting epicardial stenosis to assessment of coronary microvascular function. Recent studies have suggested that MPR may improve risk stratification of patients with known or suspected CAD. MPR has traditionally been measured using PET or CMR time-intensity curves. However, these techniques are cumbersome, require radiation (for PET) and are not practical for routine clinical practice. Measurement of coronary sinus (CS) flow with phase-contrast MRI is an alternative, simple method for assessing MPR. The aim of this study was to identify the clinical determinants of MPR using this method in patients with symptoms of possible myocardial ischemia presenting for CMR stress testing.