Intravascular Molecular Imaging: Near-Infrared Fluorescence as a New Frontier

Abstract

Despite exciting advances in structural intravascular imaging [intravascular ultrasound (IVUS) and optical coherence tomography (OCT)] that have enabled partial assessment of atheroma burden and high-risk features associated with acute coronary syndromes, structural-based imaging modalities alone do not comprehensively phenotype the complex pathobiology of atherosclerosis. Near-infrared fluorescence (NIRF) is an emerging molecular intravascular imaging modality that allows for in vivo visualization of pathobiological and cellular processes at atheroma plaque level, including inflammation, oxidative stress, and abnormal endothelial permeability. Established intravascular NIRF imaging targets include macrophages, cathepsin protease activity, oxidized low-density lipoprotein and abnormal endothelial permeability. Structural and molecular intravascular imaging provide complementary information about plaque microstructure and biology. For this reason, integrated hybrid catheters that combine NIRF-IVUS or NIRF-OCT have been developed to allow co-registration of morphological and molecular processes with a single pullback, as performed for standalone IVUS or OCT. NIRF imaging is approaching application in clinical practice. This will be accelerated by the use of FDA-approved indocyanine green (ICG), which illuminates lipid- and macrophage-rich zones of permeable atheroma. The ability to comprehensively phenotype coronary pathobiology in patients will enable a deeper understanding of plaque pathobiology, improve local and patient-based risk prediction, and usher in a new era of personalized therapy.

Recent Advances in Transducers for Intravascular Ultrasound (IVUS) Imaging

“…NIRF imaging is an emerging cellular and molecular imaging technique that uses laser induced NIR signal to stimulate NIRF emission of vessel wall and plaques that have injected with fluorescence-imaging agents [174]. It has been demonstrated that the activity of plaque inflammation can be detected by injecting an imaging contrast agent to the sites of the inflamed tissues [175].…”

Mechanically Rotating Intravascular Ultrasound (IVUS) Transducer: A Review

“…Thus, more than one imaging modality has been integrated into the IVUS images. For example, IVUS/intravascular optical coherence tomography (IV-OCT) [184][185][186][187][188][189] and IVUS/near-infrared spectroscopy (NIRS) [190][191][192][193][194] are currently available for practical use, and IVUS images with near-infrared fluorescence (NIRF) [195][196][197][198][199], fluorescence lifetime imaging (FLIm) [200][201][202][203][204], and intravascular photoacoustic (IVPA) [123,[205][206][207][208] have been investigated at the laboratory level. These combinations can complement the drawbacks of each imaging modality while providing more clinical information.…”

Untethered Microrobots for Active Drug Delivery: From Rational Design to Clinical Settings

“…Intravascular ultrasound (IVUS) guidance of percutaneous coronary intervention (PCI) significantly reduces major cardiac adverse events. [ 81 ] The acquisition time of imaging of ultrasound is much faster than those of MRI, Positron Emission Computed Tomography (PET), and X‐ray. The wireless magnetic motion control and planning of soft untethered grippers demonstrated the ability of real‐time ultrasound imaging feedback, where visual feedback cannot be provided via cameras.…”