4-Dimensional Modeling of the Mitral Valve by Real-time 3-Dimensional Transesophageal Echocardiography

Objectives: The complexity of the mitral valve (MV) anatomy and function is not yet fully understood. Assessing especially the dynamic movement and interaction of MV components to define MV physiology during the complete cardiac cycle remains a challenge. We herein describe a novel semi-automated 4-dimensional MV model.

Methods: The model applies quantitative analysis of the MV during a complete cardiac cycle based on real-time 3-dimensional echocardiography (RT3DE) data. In 18 consecutive surgical patients with isolated coronary artery diseases (CAD) (mean age 68 ± 10 years; 13 male) and left ventricular ejection fraction of mean 54 ± 13%, RT3DE was performed. The MV annulus and leaflets were semi-automatically reconstructed. Mitral annular (anteroposterior and anterolateral-posteriomedial diameter, circumference, area) and leaflet dimensions (orifice area, intercommissural distance) were acquired. Variability and reproducibility (intraclass correlation coefficient, ICC) for interobsever and intraobserver comparison were quantified at 4 time points of the cardiac cycle (mid-systole, end-systole, mid-diastole, end-diastole).

Results: Mitral annulus dimensions provided excellent reliable and reproducible measurements throughout the cardiac cycle for interobserver (variability range, 0.5–1.5%; ICC range, 0.895–0.987) and intraobserver (variability range, 0.5–1.6%; ICC range, 0.827–0.980) comparison, respectively. Leaflet dimensions showed higher variability and lower correlation in systolic phase (variability range, 0.6–22.4%; ICC range, 0.446–0.915). Whereas leaflet parameters showed high reliability in diastolic phase (variability range, 0.6–9.1%; ICC range, 0.750–0.986).

Conclusions: This 4-dimensional model allows detailed reconstruction including quantification of the complex MV structure and dynamic for the first time. The model has proven feasibility, reliability and repeatability.