Anatomy of mitral annulus insights from non-invasive imaging techniques.

The mitral annulus (MA) is not a continuous ring of connective tissue from which are suspended mitral leaflets. Instead, it is a much more complex structure made up of a mix of fibrous, muscular, and adipose tissues. MA is a key structure in any type of mitral valve repair and recently it has been targeted for transcutaneous devices. Thus, a deep understanding of MA anatomy has never been more important. Traditionally, cardiac anatomy has been described using anatomic specimens. Currently, sophisticated non-invasive techniques allow imaging of MA with a richness of anatomical details unimaginable only two decades ago. The aim of this review is to provide a better understanding of the peculiar aspects of MA as they are revealed through these imaging techniques and discuss clinical implications related to this complex structure.