In Vivo Plaque Characterization Using Intravascular Ultrasound–Virtual Histology in a Porcine Model of Complex Coronary Lesions

Abstract

Objective-To determine the accuracy of detection of different tissue types of intravascular ultrasound-virtual histology (IVUS-VH) in a porcine model of complex coronary lesions. Methods and Results-Coronary lesions were induced by injecting liposomes containing human oxidized low-density lipoprotein into the adventitia of the arteries. IVUS-VH imaging was performed in vivo at 8.2Ϯ1.6 weeks after injection. A total of 60 vascular lesions were analyzed and compared with their correspondent IVUS-VH images. Correlation analysis was performed using linear regression models. Key Words: animal model Ⅲ intravascular ultrasound Ⅲ vulnerable plaque C omplex atherosclerotic plaques containing specific morphological features appear to be responsible for the majority of major coronary events. 1-4 Therefore, the accurate identification and characterization of these lesions has become one of the major challenges of interventional cardiology. 5 Several catheter-based imaging devices designed and built to characterize such features are currently undergoing development. 6 -10 Mainly because of the lack of a large animal model of atherosclerotic vascular disease, the initial development of these technologies is based on the construction of mathematical algorithms based on data acquired from ex vivo evaluation of postmortem human arterial specimens. Therefore, the translation of these algorithms of detection into an in vivo setting may not be universally accurate.Virtual histology is an intravenous ultrasound (IVUS)-based technology that studies the spectral analysis of the radio frequency signals backscattered from the plaque during IVUS imaging and reconstructs the morphology of the plaque through color-coded maps. 11 Although this technique has been validated in vitro and ex vivo in human coronary arteries [11][12][13][14] and preliminary clinical experience has been published, 15,16 little data have been published on histological correlates of images acquired in vivo. 17 In the present study, we describe the histological characteristics of complex coronary lesions analyzed in vivo using intravascular ultrasoundvirtual histology (IVUS-VH) in a porcine model of disease.

Tissue Characterization of Coronary Plaques Comparison of Integrated Backscatter Intravascular Ultrasound With Virtual Histology Intravascular Ultrasound

“…A recent in vivo study using a porcine model reported that IVUS-VH was not accurate in detecting the area of each specific component within the corresponding histological specimen. 30 In the present study, neither the sensitivity nor the specificity of IVUS-VH in detecting different tissue types was as robust as validated in previous ex vivo studies. In our direct qualitative comparison, the overall agreement between the histological and IVUS-VH diagnoses was not as high ( =0.30) as in the quantitative comparison ( =0.73).…”

“…This tendency is consistent with previously-reported results. 30 In contrast, good in-vivo diagnostic accuracy of IVUS-VH compared with histology has been reported, using tissue samples obtained by directional coronary atherectomy (DCA). 24 The reason for the discrepancy in diagnostic accuracy for tissue characterization may be explained as follows.…”

Early Effect of Lipid-Lowering Therapy With Pitavastatin on Regression of Coronary Atherosclerotic Plaque Comparison With Atorvastatin

“…As described in many reports, it is possible that thrombus was present in the observation of regression of the PV in the acute phase because their discrimination is difficult on IVUS, and this might also have influenced the results. Moreover, the accuracy and reproducibility of identification of tissue properties on VH-IVUS might be uncertain 31 and this also requires further study. The study focused on the effects of statins over a short period, but long-term observation is necessary to judge the clinical efficacy.…”

Lipid detection in atherosclerotic human coronaries by spectroscopic intravascular photoacoustic imaging

“…IVUS radiofrequency data analysis techniques for tissue characterization, namely VH-IVUS (20 MHz, phased-array transducer, Volcano Therapeutics), and iMap (40 MHz, mechanical-type transducer, Boston Scientific), have been developed as an extension to grayscale imaging [8]. However, the accuracy of VH-IVUS in complex lesions in a porcine model was limited [9,10]. Significant and systematic variability in plaque composition estimates was found in a study comparing VH-IVUS and iMap in vivo [11].…”