Intravascular ultrasound (IVUS) is a valuable tool that complements angiography in the diagnosis and treatment of coronary disease. While angiography provides a 2D view of the lumen, IVUS offers a tomographic assessment of lumen area, plaque size, distribution, and composition. IVUS is safe and has been shown to detect occult disease in angiographically normal sites. It is particularly useful in identifying atheromas at risk of rupture and in evaluating transplant vasculopathy. IVUS-derived residual plaque burden is a key predictor of clinical outcomes. It also helps in understanding arterial remodeling, which refers to changes in vascular dimensions during atherosclerosis. IVUS can detect negative remodeling, which contributes to luminal stenosis. However, IVUS has limitations, including the difficulty in distinguishing between different tissue types and the potential for artifacts to affect image quality. IVUS is not routinely used for stent optimization, and there is no consensus on optimal procedural endpoints. Despite these limitations, IVUS has emerged as the optimal method for detecting transplant vasculopathy and has been used to guide interventions such as angioplasty and atherectomy. IVUS has also been used to evaluate the effectiveness of brachytherapy and to assess the outcomes of stent placement. New and emerging applications for IVUS are continuing to evolve, particularly in atherosclerosis regression-progression trials. IVUS is currently used in a growing number of coronary interventions, with an average of 5% to 8% of interventions performed with IVUS guidance. The use of IVUS varies across different regions, influenced by factors such as reimbursement and practice patterns. IVUS is expected to play an increasingly important role in the future of coronary imaging and intervention.Intravascular ultrasound (IVUS) is a valuable tool that complements angiography in the diagnosis and treatment of coronary disease. While angiography provides a 2D view of the lumen, IVUS offers a tomographic assessment of lumen area, plaque size, distribution, and composition. IVUS is safe and has been shown to detect occult disease in angiographically normal sites. It is particularly useful in identifying atheromas at risk of rupture and in evaluating transplant vasculopathy. IVUS-derived residual plaque burden is a key predictor of clinical outcomes. It also helps in understanding arterial remodeling, which refers to changes in vascular dimensions during atherosclerosis. IVUS can detect negative remodeling, which contributes to luminal stenosis. However, IVUS has limitations, including the difficulty in distinguishing between different tissue types and the potential for artifacts to affect image quality. IVUS is not routinely used for stent optimization, and there is no consensus on optimal procedural endpoints. Despite these limitations, IVUS has emerged as the optimal method for detecting transplant vasculopathy and has been used to guide interventions such as angioplasty and atherectomy. IVUS has also been used to evaluate the effectiveness of brachytherapy and to assess the outcomes of stent placement. New and emerging applications for IVUS are continuing to evolve, particularly in atherosclerosis regression-progression trials. IVUS is currently used in a growing number of coronary interventions, with an average of 5% to 8% of interventions performed with IVUS guidance. The use of IVUS varies across different regions, influenced by factors such as reimbursement and practice patterns. IVUS is expected to play an increasingly important role in the future of coronary imaging and intervention.