3D cellular-resolution imaging in arteries using few-mode interferometry

Cross-sectional visualisation of the cellular and subcellular structures of human atherosclerosis in vivo is significant, as this disease is fundamentally caused by abnormal processes that occur at this scale in a depth-dependent manner. However, due to the inherent resolution-depth of focus tradeoff of conventional focusing optics, today’s highest-resolution intravascular imaging technique, namely, optical coherence tomography (OCT), is unable to provide cross-sectional images at this resolution through a coronary catheter. Here, we introduce an intravascular imaging system and catheter based on few-mode interferometry, which overcomes the depth of focus limitation of conventional high-numerical-aperture objectives and enables three-dimensional cellular-resolution intravascular imaging in vivo by a submillimetre diameter, flexible catheter. Images of diseased cadaver human coronary arteries and living rabbit arteries were acquired with this device, showing clearly resolved cellular and subcellular structures within the artery wall, such as individual crystals, smooth muscle cells, and inflammatory cells. The capability of this technology to enable cellular-resolution, cross-sectional intravascular imaging will make it possible to study and diagnose human coronary disease with much greater precision in the future. A technique that provides subcellular-level images of the heart’s vascular system could allow scientists to study and diagnose human coronary disease with much greater precision. Intravascular optical coherence tomography is the conventional method for assessing the build-up of coronary plaque, which narrows arteries and leads to coronary artery disease. However, the technique has a lateral resolution of only 30 microns and is unable to provide images at the subcellular level, which is key to understanding the disease. Now, Guillermo Tearney and colleagues from Department of Pathology and Wellman Center at Massachusetts General Hospital and Harvard Medical School, in the United States, have developed a few-mode interferometry intravascular imaging system with a resolution of around 3 microns, and can provide images of cellular and subcellular structures within the artery wall, such as individual crystals, smooth muscle cells, and inflammatory cells.