Optical coherence tomography accurately identifies intermediate atherosclerotic lesions—An in vivo evaluation in the rabbit carotid artery

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.