Hybrid intravascular imaging: recent advances, technical considerations, and current applications in the study of plaque pathophysiology

Abstract

Cumulative evidence from histology-based studies demonstrate that the currently available intravascular imaging techniques have fundamental limitations that do not allow complete and detailed evaluation of plaque morphology and pathobiology, limiting the ability to accurately identify high-risk plaques. To overcome these drawbacks, new efforts are developing for data fusion methodologies and the design of hybrid, dual-probe catheters to enable accurate assessment of plaque characteristics, and reliable identification of high-risk lesions. Today several dual-probe catheters have been introduced including combined near infrared spectroscopy-intravascular ultrasound (NIRS-IVUS), that is already commercially available, IVUS-optical coherence tomography (OCT), the OCT-NIRS, the OCT-near infrared fluorescence (NIRF) molecular imaging, IVUS-NIRF, IVUS intravascular photoacoustic imaging and combined fluorescence lifetime-IVUS imaging. These multimodal approaches appear able to overcome limitations of standalone imaging and provide comprehensive visualization of plaque composition and plaque biology. The aim of this review article is to summarize the advances in hybrid intravascular imaging, discuss the technical challenges that should be addressed in order to have a use in the clinical arena, and present the evidence from their first applications aiming to highlight their potential value in the study of atherosclerosis.

Intravascular optical coherence tomography [Invited]

“…16 and 17). A discussion of other hybrid modalities is somewhat outside the scope of this review, but interested readers my enjoy another survey that has recently summarized efforts on this front [124]. Considering the unique capabilities of OCT, the progress that has been made to date with developing, validating, commercializing, and disseminating intravascular systems, and the advances with its utilization as a powerful research tool for investigating coronary atherosclerosis and the response of disease to intervention, as well as its potential role in routinely guiding interventions, it is clear that this technology will continue to make significant impact in cardiology.…”

Invasive or non-invasive imaging for detecting high-risk coronary lesions?

“…In addition, NIRS does not enable visualization and assessment of the lumen, outer vessel wall dimensions, and plaque burden and lacks image depth resolution that enables localization of the necrotic core within the plaque and differentiation of TCFA from thick cap fibroatheromas. To overcome these limitations, efforts were made to spectroscopically assess fibrous cap thickness and develop dual-probe imaging catheters that will provide simultaneous assessment of plaque characteristics from two imaging modalities with complementary strengths, thus enabling a more accurate characterization of plaque pathobiology [61,62].…”

“…Moreover, efforts are made to develop other invasive imaging techniques such as intravascular magnetic resonance imaging (MRI) or Raman spectroscopy [82,83]. These modalities are expected to enable not only more accurate evaluation of plaque morphology but also its biology and predict atherosclerotic evolution (Figure 2) [61,62].…”

“…Two studies compared the plaque burden estimations of black-blood MRI and IVUS and the first showed a good correlation between MRI and IVUS estimations while in the other report, there was a weak association between MRI and IVUS [110,111]. [62] and Abran et al [84]. Full color available online.…”

Understanding Why and When Optical Coherence Tomography Does Not Detect Vulnerable Plaques

“…IVUS or OCT+assessment of endothelial shear stress? The many potential combinations have been summarized in a review article by Bourantas et al 30 Many of these combinations are technically possible although some are more practical than others; and issues of intellectual property, financing, ease-of-use, and adoption may limit the commercialization of certain combinations.…”