Role of Cardiovascular Magnetic Resonance in the Assessment of Native Aortic Regurgitation With Insights on Mixed and Multiple Valvular Heart Disease: A Narrative Review

Cardiovascular magnetic resonance imaging (CMR) has received extensive validation for the assessment of valvular heart disease (VHD) and offers an accurate and direct method for the quantification of aortic regurgitation (AR). According to the current guidelines, CMR represents a useful second-line investigation in patients with poor acoustic windows or when echocardiography is inconclusive, for example, in cases of multiple or eccentric aortic jets. Without ionizing radiation exposure, CMR provides in-depth information not only on the severity degree of AR, providing a precise quantification of regurgitant volume and fraction, but also on cardiac structure and function, being recognized as the gold standard for the assessment of heart chamber size and systolic function. CMR allows a free choice of cardiac imaging planes and provides further information on the myocardium, thanks to the tissue characterization ability offered by several sequences, such as the late gadolinium enhancement technique. The possibilities offered by CMR become even more interesting in the context of mixed and multiple VHD, where the echocardiographic assessments often encounter difficulties in the quantification of each single valve lesion. The current scientific data support a greater expansion of CMR in this field, thanks to its additional advantages for the diagnosis, risk stratification, and to guide treatment. This review investigates the current CMR techniques and protocols in AR, with special insights into the evaluation of mixed aortic valve disease and multiple VHD including AR.