Comparison of CMR and echocardiography in aortic regurgitation. Comparison of CMR and echocardiography in aortic regurgitation. In 109 asymptomatic patients with moderate or severe aortic regurgitation on echocardiography, prognosis was better related to the regurgitant fraction on CMR with a cut-point of 33%.The graph shows CMR regurgitant fraction ≤ 33% in blue and >33% in red. The regurgitation was either moderate or severe by echocardiography in both of these two CMR groups. John B Chambers et al. Open Heart 2016;3:e000330 ©2016 by British Cardiovascular Society