Broadband Fiber Optic Rotary Joint for Clinical Multimodal Optical Coherence Tomography

Intravascular optical coherence tomography (OCT) is a diagnostic imaging tool that provides high-resolution structural information inside arteries, which other imaging modalities cannot provide. Recently, fluorescence lifetime imaging (FLIm) has been integrated with OCT (FLIm-OCT) to enhance diagnoses of coronary artery disease by providing additional biochemical insights into atherosclerotic plaque. However, achieving high efficiency for both imaging modalities is challenging due to the broad spectral range of FLIm-OCT light sources. Here, we present a compact, free space-based multimodal fiber optical rotary joint (FORJ) designed for clinical FLIm-OCT imaging. The proposed custom-built rotary collimator, incorporating a ball lens, efficiently combines a broad spectral range from 355 nm to 1360 nm. Our compact co-axially rotating FORJ enables high-speed, stable scanning suitable for clinical applications. We successfully obtained FLIm-OCT images of human coronary arteries in vivo, successfully imaging various types of plaque.