ABSTRACT
Real-time ultrasound imaging originated in the late 1960s following the development of linear array transducers for visualizing cardiac chambers and valves.[1] The first transluminal images of human arteries were recorded by Yock and colleagues in 1988, when a miniaturized and single-transducer system was placed within the coronary arteries.[2] Ever since, intravascular ultrasound (IVUS) has become an increasingly important catheter-based imaging technology. In contemporary clinical practice, the major utility of IVUS is to guide and optimize stent implantation, especially in complex lesion subsets, including bifurcations and during left main coronary artery (LMCA) intervention.[3] IVUS can also inform management of lesions of intermediate angiographic stenosis, providing data as to when revascularization can be safely deferred.[4] As IVUS directly images the full thickness of the coronary arterial wall, its use allows measurement of plaque size, distribution, and composition.[5] Thus, IVUS has become established as the method of choice for the serial assessment of changes in atherosclerotic plaque burden in numerous progression-regression trials. Spectral analysis of the radiofrequency IVUS signals, termed virtual histology (VH)-IVUS, has led to a more detailed assessment of atherosclerotic plaque composition.[6] Although this remains principally a research tool, use of VH-IVUS has led to important advances in the understanding of the natural history of atherosclerotic plaques.[7]
