This document discusses the use of intravascular ultrasound (IVUS) in chronic total occlusions (CTO) percutaneous coronary intervention (PCI), highlighting its benefits in resolving vessel architecture ambiguities and improving procedural success. It outlines ten specific applications of IVUS during CTO PCI, including cap puncture, wire positioning, and stent optimization. The document concludes that IVUS enhances efficiency, maximizes success, and may improve long-term outcomes, positioning it as an essential skill for CTO operators.