Holistic Structural Visualization of Coronary Arteries with Single-catheter Dual-modality Intravascular Imaging Combining IVUS and OFDI
Authors: Ren Jian , Shishkov Milen , Villiger Martin , Otsuka Kenichiro , Nadkarni Seemantini , Bouma Brett 
Published: June 2020

SummaryObjectivesTo test the imaging performance and practical use of a novel dual-modality intravascular imaging system combining intravascular ultrasound (IVUS) and optical coherence tomography (OCT) into a single catheter.BackgroundIVUS enables assessing coronary plaque burden, a robust metric for patient prognosis, while OCT and OFDI provide high-resolution images of coronary microstructure and detailed assessment of stent implantation. Owing to their complementary strengths, co-registering IVUS and OFDI provides a more comprehensive assessment of coronary lesions during PCI.MethodsWe developed a 2.6Fr imaging catheter integrating both IVUS and OFDI, interfacing to a dual-modality imaging console through a fast interchange connector. A novel algorithm fuses the IVUS and OFDI signals into a single combined image. We verified the performance of the two modalities and their visualization by imaging of cadaveric coronary arteries and tested practical imaging in the catheterization laboratory in swine in vivo.ResultsCoronary atherosclerotic lesions of cadaver hearts revealed complementary optical and acoustic image features. Spatial co-registration of the modalities was confirmed by high correlation of measured lumen areas. Fused into a combined visualization, dual-modality imaging offers quantitative characterization of lesions, including plaque-burden and fibrous cap thickness. Imaging in vivo does not add procedural complexity compared to conventional single modality imaging.ConclusionDual-modality IVUS/OFDI imaging with fused visualization provides improved assessment of coronary atherosclerotic lesions and is compatible with a routine clinical setting. Combining the strength of the two modalities offers unique opportunities both as a powerful research instrument and to improve clinical management of patients undergoing PCI.Visual abstractHighlights▪A catheter-based imaging system integrating ultrasound and optical frequency domain imaging enables real time intravascular holistic structural visualization (IV-HSV) of coronary arterial lesions with a single pullback during cardiac catheterization procedures.▪A computational method to automatically fuse images from both modalities generates a single complete map of vessel wall structures - the IV-HSV image, which offers holistic investigation of coronary plaque key features, such as fibrous cap thickness, calcification, and plaque burden.▪The visualization of plaque morphology along the entire extent of the coronary arterial wall reveals vital information for guiding percutaneous coronary interventions and for advancing our understanding of the pathophysiology of coronary artery diseases.Condensed abstractTo facilitate a holistic investigation of coronary arterial lesions for both basic research and clinical interventions, this work presents a catheter-based imaging system integrating IVUS and OFDI, as well as a new rendering method that computationally fuses the intrinsically co-registered images from both modalities into a single cross-sectional map of vessel structures. Imaging human cadaveric coronary arteries shows the benefit of this system by revealing near-lumen microstructures and spatially correlated macrostructures deep inside the vessel wall. The co-registration accuracy and operation in a clinical setting of this system was demonstrated through swine catheterization in vivo.