MRI may be utilized when echocardiographic images are suboptimal or to provide additional quantitative flow information with use of phase-contrast velocity encoded sequences. MRI offers multiplanar capacity in demonstration of leaflet morphology and motion and is less dependent upon patient anatomy than echocardiography. However, MRI requires multiple cardiac cycles for data collection, and imaging may be compromised in cases of arrhythmia, whereas echocardiography offers real-time valve morphologic assessment and is more mobile. MRI often shows lower peak velocities than Doppler US; however, mean flow is more accurately analyzed with phase-contrast techniques that account for variation in flow across a vessel diameter. MRI may be preferred over echocardiography in the assessment of the pulmonary valve and can be used to grade mitral, pulmonic, or aortic regurgitation if there is clinical uncertainty after echocardiography [21]. The assessment of regurgitant volume, left ventricular (LV) volume, and myocardial fibrosis may play an eventual role in risk prognosis in VHD. MRI quantified aortic insufficiency has shown correlation with surgical repair, with 85% of patients having regurgitant fraction >33% progressing to surgery, typically in <3 years [31]. Discordance between echocardiographic and MRI assessment of mitral insufficiency has been reported (r = 0.6), with MRI predicting postsurgical LV remodeling more accurately (r = 0.85, P < . 0001) than echocardiography (r = 0.32; P = . 1) in a prospective multicenter trial [32]. MRI provides high inter- and intrareader reproducibility [33] with semiautomated flow measurement in the ascending aorta and main pulmonary artery.
Dyspnea Suspected Cardiac Origin Ischemia Already Excluded . MRI may be utilized when echocardiographic images are suboptimal or to provide additional quantitative flow information with use of phase-contrast velocity encoded sequences. MRI offers multiplanar capacity in demonstration of leaflet morphology and motion and is less dependent upon patient anatomy than echocardiography. However, MRI requires multiple cardiac cycles for data collection, and imaging may be compromised in cases of arrhythmia, whereas echocardiography offers real-time valve morphologic assessment and is more mobile. MRI often shows lower peak velocities than Doppler US; however, mean flow is more accurately analyzed with phase-contrast techniques that account for variation in flow across a vessel diameter. MRI may be preferred over echocardiography in the assessment of the pulmonary valve and can be used to grade mitral, pulmonic, or aortic regurgitation if there is clinical uncertainty after echocardiography [21]. The assessment of regurgitant volume, left ventricular (LV) volume, and myocardial fibrosis may play an eventual role in risk prognosis in VHD. MRI quantified aortic insufficiency has shown correlation with surgical repair, with 85% of patients having regurgitant fraction >33% progressing to surgery, typically in <3 years [31]. Discordance between echocardiographic and MRI assessment of mitral insufficiency has been reported (r = 0.6), with MRI predicting postsurgical LV remodeling more accurately (r = 0.85, P < . 0001) than echocardiography (r = 0.32; P = . 1) in a prospective multicenter trial [32]. MRI provides high inter- and intrareader reproducibility [33] with semiautomated flow measurement in the ascending aorta and main pulmonary artery.