This chapter provides a practical guide to computed tomography (CT) planning for transcatheter aortic valve implantation (TAVI), focusing on accurate anatomical measurements using DICOM software such as Horos™ or Osiri XMD™. The step-by-step approach includes assessment of the aortic annulus, coronary ostia, sinus of valsalva (SOV), left ventricular outflow tract (LVOT), ascending aorta, and iliofemoral access vessels. Detailed instructions are provided for multiplanar reconstruction, annulus plane identification, nadir alignment for implant projection, and valve angulation measurement. Strategies for evaluating native calcifications and generating three−/four-dimensional (3D/4D) reconstructions to optimize procedural planning are also included. This structured approach ensures standardized and reproducible measurements essential for prosthesis selection, procedural strategy, and minimizing complications during TAVI.