Optical Coherence Tomography (OCT)

What is Optical Coherence Tomography (OCT)?

If a conventional angiogram is a static photograph of a blood vessel taken from the outside, OCT is an intra-luminal, “4K Ultra HD” quality video captured from the very inside of the vessel.

How Does OCT Work?

OCT represents an adaptation of high-resolution optical technology originally developed for ophthalmology (retinal imaging) to evaluate coronary arteries.

• Infrared Light Imaging: An ultra-thin imaging catheter is advanced into the artery, emitting near-infrared light from its distal tip.
• Exceptional Spatial Resolution: Because it relies on light waves rather than sound, OCT delivers a spatial resolution approximately 10 times higher than Intravascular Ultrasound (IVUS). It can capture structural details at a microscopic scale of 10 to 15 microns (thinner than a single strand of human hair).
• Rapid Automated Pullback: As the catheter is automatically pulled back through the vessel, it scans the lumen in a matter of seconds, reconstructing a comprehensive 3-dimensional, high-definition volumetric map of the entire segment.

Clinical Efficacy: What is it Used For?

OCT serves as an indispensable tool for interventional cardiologists in clinical scenarios requiring microscopic precision:

• Thrombus (Blood Clot) Detection: It visualizes intra-luminal thrombi with greater clarity than any other imaging modality. This makes it an unparalleled tool during acute myocardial infarction (heart attack) to definitively identify the culprit lesion.
• Plaque Rupture and Vulnerability Assessment: OCT can measure the thickness of the fibrous cap overlying an atheromatous plaque. Detecting a thin-cap fibroatheroma (TCFA) or microscopic fissures allows clinicians to identify vulnerable plaques and preemptively prevent an impending myocardial infarction.
• Precision Stent Optimization: It provides detailed evaluation of stent deployment, verifying perfect vessel wall apposition down to the micron level. It accurately detects edge dissections (tissue tissue tears caused by the stent) or incomplete strut expansion.
• Long-Term Neointimal Tissue Evaluation: For patients with previously implanted stents, OCT is utilized to evaluate the healing process by verifying whether the stent struts have been adequately covered by a healthy layer of endothelial cells or if intimal hyperplasia (re-narrowing) has occurred.