“…Furthermore, over-and underestimation of LV volumes in humans [64] and phantoms [65,66] have been described comparing different imaging methods, e.g., native 2D-and 3D echocardiography, contrast echocardiography, CMR, and computed tomography. Recently, conclusive LV volume assessment by 2D echocardiography was illustrated if image quality is adequate [67][68][69][70]. The differences in LV volumes between 2D echocardiography Table 2 Proposal to classify primary mitral regurgitation (PMR) more in detail with respect to specific echocardiographic findings, the chronicity of the underlying diseases, and the clinical complaints of the patients and CMR can be minimized by triplane, 3D-, and contrast echocardiography [71,72].…”