Three-dimensional assessment of the mitral valve in clinical practice.

Three-dimensional echocardiography (3DE), via both transthoracic and transoesophageal approaches, has become an essential tool in the assessment of mitral valve (MV) disease, providing detailed anatomical and functional insights fundamental to both diagnosis and therapeutic planning. By offering a unique volumetric perspective, 3DE allows a comprehensive visualization of the entire MV apparatus, enhancing the capacity to appreciate anatomical and functional details. In mitral regurgitation (MR), 3DE adds pivotal information about leaflet morphology, annular geometry, and sub-valvular structures across all Carpentier subtypes, playing a central role in surgical and percutaneous procedural planning. 3D colour-mode imaging improves spatial localization of regurgitant jets and enables advanced MR quantification techniques. Specifically, 3D proximal isovelocity surface area and 3D vena contracta area offer improved accuracy over 2D methods, particularly in functional MR, and in multiple or complex jets. Additionally, the 3D indirect volumetric method and emerging semi-automated software are further tools for MR quantification. In mitral stenosis, 3D planimetry via transthoracic and transoesophageal echocardiography provides more accurate and reproducible measurements of the MV area compared with 2D, especially in challenging anatomies or suboptimal imaging planes. 3DE, especially using the transoesophageal approach, also improves commissural evaluation, which is essential for patient selection for percutaneous valvuloplasty. Overall, 3DE has redefined MV imaging by offering unparalleled anatomical and quantitative assessment. Its integration into routine clinical practice is critical for modern echocardiography and should be considered a core competency for cardiovascular imaging specialists.