Fig. 9
From: Cardiovascular magnetic resonance in the evaluation of heart valve disease
Phase contrast velocity mapping in aortic regurgitation. Aortic flow has been measured at (a) aortic level and (b) pulmonary artery level. Note the difference in forward and reverse volumes generated by velocity mapping at the different sites. At (a) the aortic level the regurgitant fraction is 12% compared with 23% at (b) the PA level, which reflects lower calculated stroke volumes if flow is calculated at aortic level. Source: University Hospitals of Leicester NHS Trust