OCT in CARDIOLOGY (general)

Optical coherence tomography (OCT) is a micron scale, catheter based imaging technology analogous to ultrasound that uses infrared light rather than sound.1-4  In the 1990’s OCT developed rapidly as a technology with the potential for guiding intracoronary procedures and identifying those plaques that lead to acute coronary syndromes (ACS).  Initially it was a ‘tabletop” technology for imaging optically transparent samples at extremely slow data acquisition rates.1, 5, 6, 13  By the end of the millennium, it’s potential for imaging thin capped fibroatheroma (TCFA) and stents was established, direct comparisons were made with high frequency ultrasound (IVUS), and ultimately imaging was performed in vivo, at video rate through small catheters.7-9, 14  In addition, adjuvant techniques such polarization sensitive OCT (PS-OCT), image processing, SOC spectroscopy, and elastography were developed that only further advanced its ability to characterize tissue above structural imaging.10-12  Therefore, in view of the tremendous potential of this technology as it entered the decade, why has it not yet received general acceptance by the cardiology community?  More specifically, other than its advantages as a research tool, will this technology ultimately be of benefit in managing patients?  Clinical studies in the early part of this decade were predominately observational and the technology was not readily available to the majority of clinical scientists with extensive backgrounds in clinical trails, nor basic researches with experience in hypothesis driven research14-23.  In addition, much research focused on specific technical issues, many of which may not have ultimately advanced the field without a defined clinical application.  But as OCT systems have recently become available to large numbers of skilled clinical and basic scientists, it has been invaluable in studying, for example, mechanisms for late acute occlusion in drug eluding stent (DES) placement (ex; neointima growth at 1 year) although its role in managing these patients has yet to be established.  Similarly, while its ability to identify TCFA is superior to any clinical technology, a fact known for over a decade, minimal studies were performed which sub classified these plaques by markers into the small percentage that lead to ACS.  This is in spite of a wide range of potential adjuvant techniques available toward this endpoint (example PS-OCT and elastography) 10,11.  As it was over 15 years ago, OCTs greatest potential lies in the identification of plaque leading to ACS and managing stent placement.   A recent review examines the path OCT has taken in intracoronary imaging, state of our current knowledge of the pathophysiology of relevant clinical scenarios (ex; TCFA rupture and stent placement), and potential paths for future clinical research that can lead to its general acceptance by the cardiology community in patient management 24.

References

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24. 24.Brezinski, M.E., Current Capabilities and Challenges for Optical Coherence Tomography as a High-Impact Cardiovascular Imaging Modality. Circulation. 2011; 123: 2913-2915.