Intracoronary ultrasound allows in vivo examination of the various layers of the wall of arteries affected by atherosclerosis. Its use in the catheterisation laboratory has therefore allowed better understanding of the mechanism of the action of the various angioplasty procedures, allowing better guidance of the indications and better control of these techniques. It also helps to guide these procedures, thereby facilitating an optimal immediate result, which determines the long-term outcome. The characteristics of intracoronary ultrasound (high resolution, proximity of the arterial wall, echogenicity of constituents of the plaque) make it the instrument of choice to study the composition and structure of the plaque, which determine the clinical presentation and active potential, especially the risk of complications (rupture). The development of image and crude acoustic signal processing techniques have improved the performance of the analysis of these documents and raise hopes of one day being able to predict and anticipate plaque rupture.