Optical coherence tomography accurately identifies intermediate atherosclerotic lesions--an in vivo evaluation in the rabbit carotid artery

Abstract Objective: We tested the ability of optical coherence tomography (OCT) to identify very early stages of atherosclerosis in vivo. Methods: Twelve New Zealand white male rabbits (weight 3.5–4.0 kg) underwent perivascular electrical injury of the common carotid arteries, and were then fed a cholesterol-rich diet. At 43±16 (range 27–63) days after injury, arteries were imaged by OCT, then rabbits were euthanized and vessels processed for histology. Results: A total of 14 carotid arteries were imaged by OCT and histology; 22 atherosclerotic lesions were identified, 16 (73%) occurring at the site of the electrical injury. At histology, 4 lesions were defined as Stary type I (isolated macrophages), 8 as type II (intracellular lipid accumulations), and 10 as type III (small extracellular lipid pools). No advanced (≥type IV) lesions were documented. OCT failed to detect any type I lesions, but correctly defined a minority (2/8, 25%) of type II lesions and the majority (8/10, 80%) of type III lesions. For type III lesions, sensitivity, specificity and diagnostic accuracy of OCT were 80%, 95%, and 95%, respectively. Conclusions: OCT can accurately detect intermediate (type-III) atherosclerotic lesions in vivo, but still fails to identify earlier stages of atherosclerosis.