Echocardiography is the primary imaging modality to assess the location and quantify the severity of pros- thetic valve regurgitation, often requiring both TTE and TEE approaches.1,3 Although TTE provides supe- rior assessment of transvalvular gradients, chamber sizes, and function, TEE is better suited to identify the cause and location of regurgitation and is essential for prosthetic mitral valve because of acoustic shadow- ing on TTE. Even with prosthetic aortic valves, acous- tic shadowing may affect detection of a paravalvular leak by either TTE or TEE, with TTE being suboptimal to assess posterior paravalvular leak and TEE subop- timal to assess anterior defects.3 The Valve Academic Research Consortium (VARC) has suggested an approach for assessment of paravalvular leak severity and constructed a 5-class grading scheme.7 2. 3D echocardiography plays a significant role in determining the precise location and size of the paravalvular leak in patients undergoing interven- tion. For a successful transcatheter paravalvular leak closure, adequate paravalvular leak assess- ment includes 1) precise location of the defect(s), 2) precise dimensions, 3) orientation of the defect in relation to the sewing ring and prosthetic valve occluders or leaflets, and 4) location and orienta- tion of the subvalvular structures. Real-time 3D TEE allows optimal visualization of the defects and direct guidance for catheter movement and positioning of the implanted device(s) during the transcatheter 3D TEE also allows assessment of residual regurgitation after device placement. Limitations of 3D TEE include artifacts of ultrasound imaging (eg, dropout, acoustic shadowing, rever- beration artifacts) and reduced temporal and spatial Transcatheter closure using intracardiac echocardiography guidance is possible and allevi- ates the need for conscious sedation or anesthesia but allows only 2D and color Doppler imaging.9 11.9.2. 