Abstract For several decades, contrast angiography has served as the principal imaging modality used to assess the anatomic severity of coronary artery disease. Recent technical advances in acoustics and microelectonics have permitted development and refinement of miniaturized ultrasound devices capable of real-time tomographic coronary imaging. This approach, intravascular ultrasound, represents an emerging alternative to angiography for direct visualization of coronary anatomy during diagnostic and interventional catheterization. Clinical studies comparing angiography to intravascular ultrasound have demonstrated frequent differences in quantitative or qualitative findings. Accordingly, intraluminal ultrasound imaging is increasingly utilized to confirm, refute, or supplement angiographie data in patients with coronary disease. The discrepancies between angiography and intravascular ultrasound can be explained by the characteristics of these two different imaging techniques. Angiography, which portrays the vessel as a silhouette of the lumen, whereas ultrasound depicts the coronary from a tomographic perspective, providing cross-sectional images that portray not only the lumen, but also the deeper intramural structures.