**2.2 3-dimensional echocardiography**

3-Dimensional (3D) echocardiography is crucial in assessing AR severity. While numerous 2-Dimensional (2D) echocardiography parameters can be used to quantify AR, it remains challenging due to variations in the scan plane and irregularities in the shape of the vena contracta jet. 3D echocardiography, specifically measuring the vena contracta area (3D-VCA), provides a direct and accurate evaluation. Studies have shown that severe AR can be detected with a sensitivity of 89% and specificity of 98% using a 3D-VCA cutoff of 32 mm<sup>2</sup> [16]. 2D-derived parameters such as proximal iso-velocity surface area (PISA) and regurgitant volume (RVol) affected by geometric assumptions, angle correction limitations, and difficulty assessing multiple jets. Full-volume color Doppler echocardiography in 3D has been reported to be more accurate than 2D-PISA, especially for eccentric or multiple jets [17]. Moreover, 3D color Doppler echocardiography has demonstrated high accuracy and reproducibility for AR evaluation, exhibiting a strong correlation with cardiac magnetic resonance (CMR) imaging, considered the gold standard [18].
