Transcatheter aortic valve implantation has been introduced into the clinical arena as an alternative to traditional surgical aortic valve replacement for these high-risk patients. The anatomic suitability is decided by a number of imaging techniques including 2-dimensional transthoracic (2D TTE) and transesophageal (2D TEE) echocardiography, coronary and peripheral angiography, and computed tomography scanning from the aortic root to the common femoral artery. New insights into the anatomy of the aortic valve complex in the beating heart became possible with the rapidly increasing availability of 3-dimensional imaging techniques that have extended our concepts of the “in vivo” 3D morphology of the valve. A comprehensive understanding of the 3D anatomy of aortic root is of paramount importance for both interventionalists and experts in cardiac imaging. The purposes of this chapter are: to describe 3D TEE anatomy of normal aortic root ; to describe RT 3D TEE imaging of calcific aortic stenosis and, finally, to outline the debated role of 2D TEE and 3D TEE during the procedure.