Intracoronary Imaging and Its Use in Interventional Cardiology.

In 1971, Bom and colleagues developed one of the first catheter-based real-time imaging techniques for use in the cardiac system. By placing a set of phased-array ultrasound transducers within the cardiac chambers, it was shown that higher frequencies could be used to produce high-resolution images of cardiac structures without interference from bony structures that occurs with conventional transthoracic ultrasound imaging. By the late 1980s, my mentor at Stanford, Prof Paul G. Yock, and his colleagues had successfully miniaturized a single-transducer intravascular ultrasound (IVUS) catheter system to enable the transducer placement within coronary arteries. Over the decades since then, IVUS has become a pivotal catheter-based imaging technology worldwide, having provided practical guidance for percutaneous interventions as well as scientific insights into vascular biology in clinical settings. During this period, several other advanced imaging technologies were also developed and introduced into the clinical arena, including catheter-based optical coherence tomography (OCT), an optical analog of IVUS offering greater axial resolution at the expense of beam penetration, and intravascular near-infrared spectroscopy (NIRS), which is specifically designed to identify the lipid component within the vessel wall. While current evidence regarding the impact of intracoronary imaging on cardiovascular outcomes is founded mostly on the results of clinical IVUS studies due to its longest history in clinical application, solid data are rapidly accumulating to support the benefits of the newer imaging technologies as well. This issue of Interventional Cardiology Clinics is therefore intended to serve as an up-to-date resource of IVUS, OCT, and NIRS, not only for practicing cardiologists, residents, and students but also for researchers and engineers with aspirations to apply or advance these sophisticated catheter-based imaging technologies. In each modality, experts in the field discuss its diagnostic application, specifically focusing on vulnerable plaque and acute coronary syndrome, its practical application, and latest evidence in image-guided percutaneous coronary intervention, as well as ongoing technical efforts to further enhance the utility of the principal imaging technology. Furthermore, the use of intravascular imaging in other specific applications is addressed in dedicated articles, such as cardiac allograft vasculopathy, symptomatic myocardial bridging, and imaging-derived coronary physiology assessment. Despite recent advancements in noninvasive imaging allowing rapid and detailed visualization of cardiovascular structures, clinical demand for catheter-based imaging is growing, largely driven by increasing complexity of target lesions for percutaneous interventions as well as evolving treatment technologies that require precise procedural guidance or real-time assessment of the treatment effects. It is my hope that this focused issue will prove useful to the medical and health care engineering community, in its effort to serve as a comprehensive guide to understanding this rapidly evolving field and its role in patient care and clinical research in interventional cardiology. Being asked to serve as the guest editor of this issue has been a great privilege. However, the successful production has required the support and cooperation of a number of individuals. I would like to express my deep appreciation to all the authors, who generously contributed their time and expert knowledge to this issue, as well as the journal editor, Dr Marvin H. Eng, and the staff of Elsevier, in particular, Ms Arlene B. Campos and Ms Joanna Collett. Without their expertise, dedication, and time commitment, this issue would not have been possible.