Fig. 1

Coronary flow reserve measurement of the coronary sinus using phase contrast cine cardiovascular magnetic resonance (CMR). A–C Locations of region-of-interest (ROI) for coronary sinus blood flow measurements and phase-offset correction. D Representative blood flow in the coronary sinus. Coronary sinus blood flow typically peaks twice during the systolic and diastolic phases. CBF coronary blood flow, CFR coronary flow reserve