Circulation Journal Official Journal of the Japanese Circulation Society http://www. j-circ.or.jp ysis yields faster and more reproducible results; and (4) a variety of users (eg, cardiac anesthetists) wants to use the repeatable methodology offered by quantitative methods. Image-processing tools provide characterization of the complex 3D morphology and motion of the MV. Combined with the properties of the imaging modality and knowledge of anatomy, this yields quantitative descriptions that are useful in diagnostic and therapeutic decision-making. This review summarizes the current development and applications of quantitative analysis of the MV morphology using RT3DE.
Anatomic Consideration
MV LeafletsThe anterior leaflet (AL) is in fibrous continuity with the aortic valve and guards one-third of the anterior mitral annulus. Fine demarcations divide the AL into 3 smaller scallops. The posterior leaflet (PL) is crescent-shaped and spans the posterior n the past 5 years, advances in real-time 3-dimensional echocardiography (RT3DE) have revolutionized the imaging of the mitral valve (MV). Many studies have consistently shown the superiority of 3D transesophageal echocardiography (TEE) over 2D TEE for visualizing MV morphology. 1 RT3DE has become the imaging modality of choice for guiding MV surgery and catheter-based intervention. Currently, RT3D imaging of the MV involves mainly visualization and qualitative interpretation of volume-rendered images. This "qualitative" approach typically involves few quantitative measurements of MV morphology, and is prone to subjectivity that introduces bias, low reproducibility, and high dependency on imaging expertise.Quantitative cardiac imaging has growing importance for several reasons: (1) as imaging becomes more digital, the opportunity will create the need; (2) automated approaches to intervention and surgery design and planning are emerging from the laboratory and entering the clinic; (3) algorithm-driven anal- The mitral valve (MV) has complex 3-dimensional (3D) morphology and motion. Advance in real-time 3D echocardiography (RT3DE) has revolutionized clinical imaging of the MV by providing clinicians with realistic visualization of the valve. Thus far, RT3DE of the MV structure and dynamics has adopted an approach that depends largely on subjective and qualitative interpretation of the 3D images of the valve, rather than objective and reproducible measurement. RT3DE combined with image-processing computer techniques provides precise segmentation and reliable quantification of the complex 3D morphology and rapid motion of the MV. This new approach to imaging may provide additional quantitative descriptions that are useful in diagnostic and therapeutic decision-making. Quantitative analysis of the MV using RT3DE has increased our understanding of the pathologic mechanism of degenerative, ischemic, functional, and rheumatic MV disease. Most recently, 3D morphologic quantification has entered into clinical use to provide more accurate diagnosis of MV disease and for plannin...