Label-free classification of atherosclerosis plaque via OCT and ultraviolet autofluorescence spectroscopy.

We proposed a label-free method for the identification and classification of atherosclerosis plaques by combining optical coherence tomography (OCT) with ultraviolet autofluorescence spectroscopy (uFLS). By aligning the OCT source and the FLS excitation beams, we were able to illuminate the same spot on plaques fixed to the integrated probe, which underwent rotational scanning. This setup enabled the detection of both OCT images and uFLS spectra of the plaques in a co-localized manner. In our approach, a 1300 nm centered swept laser source was utilized for OCT imaging, while a 355 nm laser source, along with a lensed multimode fiber, served as the fluorescence probe for uFLS. The successful acquisition of OCT-uFLS images provided complementary information regarding the tomographic internal structure and biochemical components within the vessels, allowing for comprehensive identification and classification of atherosclerosis plaques. Furthermore, we achieved quantitative measurements and analysis of fluorescence spectra from three main component channels, corresponding to collagen, elastin, and lipid. This enabled us to differentiate atherosclerosis from normal vessel walls and determine the specific types. With the implementation of this dual-modal OCT-uFLS technique, it is possible to facilitate the label-free classification of various histopathological types of atherosclerosis plaques, which holds the potential for both diagnosis and image-guided ablation therapy applications.