Editors' ChoiceCardiovascular Imaging

Setting Sights on a Silent Killer

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Science Translational Medicine  20 Jul 2011:
Vol. 3, Issue 92, pp. 92ec115
DOI: 10.1126/scitranslmed.3002894

Coronary artery disease is a killer that works at the cellular level. Heart attacks occur when the endothelium of a vulnerable atherosclerotic plaque is disrupted. The ability to determine which patient has a “vulnerable” plaque that is going to rupture—causing a deadly heart attack—is determined by the pathologist, through a microsope, after the rupture has occurred. Clearly, it would benefit the patient to track down these vulnerable plaques before rupture. To this end, Liu and colleagues present a new form of optical coherence tomography (OCT), called micro-optical coherence tomography (µOCT). µOCT boasts 1- to 2-µm resolution, which allows for in vivo imaging of cellular and subcellular structures of the human coronary wall.

Liu et al. constructed an OCT system that uses a broad bandwidth light source and common-path spectral domain OCT. They highlight the system’s imaging capabilities by taking us on a tour of both human cadaver and swine atherosclerotic plaques. Starting at the plaque surface (endothelium) and then moving deeper into the necrotic core, the authors were able to image leukocytes, lipid-laden macrophages, smooth muscle cells, and cholesterol calcifications. The resolution was such that one can see leukocytes rolling along the endothelium and monocytes transmigrating the endothelium. Similarly, µOCT was able to identify microscopic features of thrombus (blood clot) formations on the surface of atherosclerotic plaques. This is important for detecting atherosclerosis because clot deposition suggests an underlying vulnerable plaque.

Liu et al. showed how µOCT can generate 3D histology and microscopy images in a real-time, in vivo setting. Intracoronary µOCT could therefore be used to monitor healing in patients who have undergone cardiac stent placement or even to help guide antiplatelet therapy duration by seeing how well the endothelium has healed. Most importantly, µOCT could be key to identifying vulnerable plaques that are the silent killers in cardiovascular disease.

L. Liu et al., Imaging the subcellular structure of human coronary atherosclerosis using micro–optical coherence tomography. Nat. Med. 10 July 2011 (10.1038/nm.2409). [Abstract]

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