Assessment of Coronary Atherosclerosis using Optical Coherence Tomography

Abstract

Optical coherence tomography (OCT) is a catheter-based imaging system that uses near-infrared light to produce cross-sectional images of the coronary arteries. With its extraordinarily high resolution (10-20 μm), OCT allows clinicians to observe various morphological features of coronary atherosclerosis in vivo. For example, intimal thickening presents as homogeneous, signal-rich regions on OCT, while fibroatheroma with a lipid-rich necrotic core is characterized by the presence of signal-poor regions with a diffuse border. Furthermore, plaque rupture is detected in 50-70% of culprit lesions of acute coronary syndrome (ACS), and plaque erosion develops over areas of intimal thickening and/or thick-cap fibroatheroma. Meanwhile, calcified nodules are common in older patients with hypertension and chronic renal disease. Platelet-rich thrombi are visualized as low backscattering structures and often detected in patients with unstable angina, whereas red blood cellrich thrombi exhibit a high backscattering structure with signal-free shadowing and are frequently noted in patients with acute myocardial infarction. Moreover, OCT-derived thin cap fibroatheroma has been shown to be a predictor of subsequent plaque progression and acute coronary events, while vasa vasorum and the macrophage density are associated with a thin fibrous cap and large necrotic core as well as increased serum levels of inflammatory biomarkers. One current challenge of OCT examinations is to detect morphologic characteristics capable of discriminating vulnerable from stable plaques. The ability to detect vulnerable plaques in vivo would allow physicians to identify patients at high risk for adverse coronary events, thus significantly helping to prevent ACS. J Atheroscler Thromb, 2014; 21:895-903.

Evaluation of coronary arterial calcification – Ex-vivo assessment by optical frequency domain imaging

“…This attenuation may be related to the pathogenesis of calcified nodule, for Sakakura et al reported that intra-calcification hemorrhage may be responsible to the development of calcified nodules [30], and red thrombus is known to be attenuated on OFDI [19,31]. On the other hand, the calcified nodule was displayed as acoustic shadow by IVUS, therefore, it is difficult to differentiate the calcified nodule from other types of calcification.…”

“…Optical coherence tomography (OCT) allows visualization of detailed features in atherosclerotic coronary arteries such as fibrous lesions, lipid-rich plaques, calcification, thrombus, and dissection [16,19,20]. While OCT has the advantage in the measurement of fibrous cap thickness over the necrotic core because of its high resolution (10e15 mm), this technology is also capable of Units and Abbreviations: OFDI, optical frequency domain imaging; PCI, percutaneous coronary intervention; IVUS, intravascular ultrasound; CTCA, computed tomographic coronary angiography; OCT, Optical coherence tomography; H&E, hematoxylin-eosin; ROC, receiver-operating characteristic; AUC, area under the ROC curve.…”

How to Look Closely to Vulnerable Atherosclerotic Plaques Using Nanoparticles

“…OCT has 10-fold higher spatial resolution than IVUS which permits the assessment to different parameters for plaque vulnerability classification: fibrous cap length, limited identification of macrophage distribution through the plaque and neovascularization. Some authors state that OCT is an ideal method for vulnerable plaque detection, mostly because OCT showed a better performance on the identification of fibrous cap disruption and erosion, intracoronary thrombus and thin-cap fibroatheroma than IVUS [12,13]. In addition, a study in which the ability of in vivo lipid pool assessment was evaluated, demonstrated the superiority of OCT when compared to IVUS, since IVUS showed only 24.1% of OCT sensitivity for this purpose.…”

Automatizáltan mérhető biomarkerek az akut myocardialis infarctus diagnosztikájában

“…A tanulmányok szerint az újonnan vizsgált necrosismarkerek (szívmio-zinkötő fehérje C és sarcoplasmás reticulum Ca 2+ -ATPáz) sokkal szívfajlagosabbak, mint a jelenleg használatosak [40,41,42]. A biomarkerek mellett olyan új képalkotó eljárások is segítik az AMI diagnózisát, mint a szív mág-neses rezonanciás képalkotás (cMRI) és az optikai koherens tomográfi a (OCT) [43,44]. Ha a szívbiomarker-csoportokban (plakk, prognosztikai, korai, necrosis) az újabban vizsgált anyagok közül valamelyik használható-sága széles körű megerősítést nyer, akkor akár teljesen átalakulhat az AMI laboratóriumi diagnosztikai eszköz-tára és módosulhat a defi níciója is.…”