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Bec J, Zhou X, Villiger M, Southard JA, Bouma B, Marcu L. Dual modality intravascular catheter system combining pulse-sampling fluorescence lifetime imaging and polarization-sensitive optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2024; 15:2114-2132. [PMID: 38633060 PMCID: PMC11019710 DOI: 10.1364/boe.516515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/08/2024] [Accepted: 02/08/2024] [Indexed: 04/19/2024]
Abstract
The clinical management of coronary artery disease and the prevention of acute coronary syndromes require knowledge of the underlying atherosclerotic plaque pathobiology. Hybrid imaging modalities capable of comprehensive assessment of biochemical and morphological plaques features can address this need. Here we report the first implementation of an intravascular catheter system combining fluorescence lifetime imaging (FLIm) with polarization-sensitive optical coherence tomography (PSOCT). This system provides multi-scale assessment of plaque structure and composition via high spatial resolution morphology from OCT, polarimetry-derived tissue microstructure, and biochemical composition from FLIm, without requiring any molecular contrast agent. This result was achieved with a low profile (2.7 Fr) double-clad fiber (DCF) catheter and high speed (100 fps B-scan rate, 40 mm/s pullback speed) console. Use of a DCF and broadband rotary junction required extensive optimization to mitigate the reduction in OCT performance originating from additional reflections and multipath artifacts. This challenge was addressed by the development of a broad-band (UV-visible-IR), high return loss (47 dB) rotary junction. We demonstrate in phantoms, ex vivo swine coronary specimens and in vivo swine heart (percutaneous coronary access) that the FLIm-PSOCT catheter system can simultaneously acquire co-registered FLIm data over four distinct spectral bands (380/20 nm, 400/20 nm, 452/45 nm, 540/45 nm) and PSOCT backscattered intensity, birefringence, and depolarization. The unique ability to collect complementary information from tissue (e.g., morphology, extracellular matrix composition, inflammation) with a device suitable for percutaneous coronary intervention offers new opportunities for cardiovascular research and clinical diagnosis.
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Affiliation(s)
- Julien Bec
- Biomedical Engineering, University of California, Davis, CA 95616, USA
| | - Xiangnan Zhou
- Biomedical Engineering, University of California, Davis, CA 95616, USA
| | - Martin Villiger
- Wellman Center for Photomedicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Jeffrey A. Southard
- Division of Cardiovascular Medicine, UC Davis Health System, University of California-Davis, Sacramento, CA 95817, USA
| | - Brett Bouma
- Wellman Center for Photomedicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Laura Marcu
- Biomedical Engineering, University of California, Davis, CA 95616, USA
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Cerpentier J, Meuret Y. Freeform surface topology prediction for prescribed illumination via semi-supervised learning. OPTICS EXPRESS 2024; 32:6350-6365. [PMID: 38439340 DOI: 10.1364/oe.510808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 01/29/2024] [Indexed: 03/06/2024]
Abstract
Despite significant advances in the field of freeform optical design, there still remain various unsolved problems. One of these is the design of smooth, shallow freeform topologies, consisting of multiple convex, concave and saddle shaped regions, in order to generate a prescribed illumination pattern. Such freeform topologies are relevant in the context of glare-free illumination and thin, refractive beam shaping elements. Machine learning techniques already proved to be extremely valuable in solving complex inverse problems in optics and photonics, but their application to freeform optical design is mostly limited to imaging optics. This paper presents a rapid, standalone framework for the prediction of freeform surface topologies that generate a prescribed irradiance distribution, from a predefined light source. The framework employs a 2D convolutional neural network to model the relationship between the prescribed target irradiance and required freeform topology. This network is trained on the loss between the obtained irradiance and input irradiance, using a second network that replaces Monte-Carlo raytracing from source to target. This semi-supervised learning approach proves to be superior compared to a supervised learning approach using ground truth freeform topology/irradiance pairs; a fact that is connected to the observation that multiple freeform topologies can yield similar irradiance patterns. The resulting network is able to rapidly predict smooth freeform topologies that generate arbitrary irradiance patterns, and could serve as an inspiration for applying machine learning to other open problems in freeform illumination design.
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Li C, Bec J, Zhou X, Marcu L. Dual-modality fluorescence lifetime imaging-optical coherence tomography intravascular catheter system with freeform catheter optics. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:076005. [PMID: 35864574 PMCID: PMC9300477 DOI: 10.1117/1.jbo.27.7.076005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 06/27/2022] [Indexed: 06/15/2023]
Abstract
SIGNIFICANCE Intravascular imaging is key to investigations into atherosclerotic plaque pathobiology and cardiovascular diagnostics overall. The development of multimodal imaging devices compatible with intracoronary applications has the potential to address limitations of currently available single-modality systems. AIM We designed and characterized a robust, high performance multimodal imaging system that combines optical coherence tomography (OCT) and multispectral fluorescence lifetime imaging (FLIm) for intraluminal simultaneous assessment of structural and biochemical properties of coronary arteries. APPROACH Several shortcomings of existing FLIm-OCT catheter systems are addressed by adopting key features, namely (1) a custom fiber optic rotary joint based on an air bearing, (2) a broadband catheter using a freeform reflective optics, and (3) integrated solid-state FLIm detectors. Improvements are quantified using a combination of experimental characterization and simulations. RESULTS Excellent UV and IR coupling efficiencies and stability (IR: 75.7 % ± 0.4 % , UV: 45.7 % ± 0.35 % ) are achieved; high FLIm optical performance is obtained (UV beam FWHM: 50 μm) contemporaneously with excellent OCT beam quality (IR beam FWHM: 17 μm). High-quality FLIm OCT image of a human coronary artery specimen was acquired. CONCLUSION The ability of this intravascular imaging system to provide comprehensive structural and biochemical properties will be valuable to further our understanding of plaque pathophysiology and improve cardiovascular diagnostics.
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Affiliation(s)
- Cai Li
- University of California, Department of Biomedical Engineering, Davis, California, United States
| | - Julien Bec
- University of California, Department of Biomedical Engineering, Davis, California, United States
| | - Xiangnan Zhou
- University of California, Department of Biomedical Engineering, Davis, California, United States
| | - Laura Marcu
- University of California, Department of Biomedical Engineering, Davis, California, United States
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Alfonso-Garcia A, Cevallos SA, Lee JY, Li C, Bec J, Bäumler AJ, Marcu L. Assessment of Murine Colon Inflammation Using Intraluminal Fluorescence Lifetime Imaging. Molecules 2022; 27:1317. [PMID: 35209104 PMCID: PMC8875403 DOI: 10.3390/molecules27041317] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 02/11/2022] [Accepted: 02/13/2022] [Indexed: 01/22/2023] Open
Abstract
Inflammatory bowel disease (IBD) is typically diagnosed by exclusion years after its onset. Current diagnostic methods are indirect, destructive, or target overt disease. Screening strategies that can detect low-grade inflammation in the colon would improve patient prognosis and alleviate associated healthcare costs. Here, we test the feasibility of fluorescence lifetime imaging (FLIm) to detect inflammation from thick tissue in a non-destructive and label-free approach based on tissue autofluorescence. A pulse sampling FLIm instrument with 355 nm excitation was coupled to a rotating side-viewing endoscopic probe for high speed (10 mm/s) intraluminal imaging of the entire mucosal surface (50-80 mm) of freshly excised mice colons. Current results demonstrate that tissue autofluorescence lifetime was sensitive to the colon anatomy and the colonocyte layer. Moreover, mice under DSS-induced colitis and 5-ASA treatments showed changes in lifetime values that were qualitatively related to inflammatory markers consistent with alterations in epithelial bioenergetics (switch between β-oxidation and aerobic glycolysis) and physical structure (colon length). This study demonstrates the ability of intraluminal FLIm to image mucosal lifetime changes in response to inflammatory treatments and supports the development of FLIm as an in vivo imaging technique for monitoring the onset, progression, and treatment of inflammatory diseases.
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Affiliation(s)
- Alba Alfonso-Garcia
- Biomedical Engineering Department, University of California, Davis, CA 95616, USA; (C.L.); (J.B.); (L.M.)
| | - Stephanie A. Cevallos
- Medical Microbiology and Immunology Department, University of California, Davis, CA 95616, USA; (S.A.C.); (J.-Y.L.); (A.J.B.)
| | - Jee-Yon Lee
- Medical Microbiology and Immunology Department, University of California, Davis, CA 95616, USA; (S.A.C.); (J.-Y.L.); (A.J.B.)
| | - Cai Li
- Biomedical Engineering Department, University of California, Davis, CA 95616, USA; (C.L.); (J.B.); (L.M.)
| | - Julien Bec
- Biomedical Engineering Department, University of California, Davis, CA 95616, USA; (C.L.); (J.B.); (L.M.)
| | - Andreas J. Bäumler
- Medical Microbiology and Immunology Department, University of California, Davis, CA 95616, USA; (S.A.C.); (J.-Y.L.); (A.J.B.)
| | - Laura Marcu
- Biomedical Engineering Department, University of California, Davis, CA 95616, USA; (C.L.); (J.B.); (L.M.)
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Kellnberger S, Wissmeyer G, Albaghdadi M, Piao Z, Li W, Mauskapf A, Rauschendorfer P, Tearney GJ, Ntziachristos V, Jaffer FA. Intravascular molecular-structural imaging with a miniaturized integrated near-infrared fluorescence and ultrasound catheter. JOURNAL OF BIOPHOTONICS 2021; 14:e202100048. [PMID: 34164943 PMCID: PMC8492488 DOI: 10.1002/jbio.202100048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 05/11/2021] [Accepted: 06/10/2021] [Indexed: 05/29/2023]
Abstract
Coronary artery disease (CAD) remains a leading cause of mortality and warrants new imaging approaches to better guide clinical care. We report on a miniaturized, hybrid intravascular catheter and imaging system for comprehensive coronary artery imaging in vivo. Our catheter exhibits a total diameter of 1.0 mm (3.0 French), equivalent to standalone clinical intravascular ultrasound (IVUS) catheters but enables simultaneous near-infrared fluorescence (NIRF) and IVUS molecular-structural imaging. We demonstrate NIRF-IVUS imaging in vitro in coronary stents using NIR fluorophores, and compare NIRF signal strengths for prism and ball lens sensor designs in both low and high scattering media. Next, in vivo intravascular imaging in pig coronary arteries demonstrates simultaneous, co-registered molecular-structural imaging of experimental CAD inflammation on IVUS and distance-corrected NIRF images. The obtained results suggest substantial potential for the NIRF-IVUS catheter to advance standalone IVUS, and enable comprehensive phenotyping of vascular disease to better assess and treat patients with CAD.
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Affiliation(s)
- Stephan Kellnberger
- Cardiovascular Research Center, Cardiology Division, Massachusetts General Hospital, Boston, MA 02114
| | - Georg Wissmeyer
- Cardiovascular Research Center, Cardiology Division, Massachusetts General Hospital, Boston, MA 02114
| | - Mazen Albaghdadi
- Cardiovascular Research Center, Cardiology Division, Massachusetts General Hospital, Boston, MA 02114
| | - Zhonglie Piao
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114
| | - Wenzhu Li
- Cardiovascular Research Center, Cardiology Division, Massachusetts General Hospital, Boston, MA 02114
| | - Adam Mauskapf
- Cardiovascular Research Center, Cardiology Division, Massachusetts General Hospital, Boston, MA 02114
| | - Philipp Rauschendorfer
- Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Neuherberg, Germany
- Chair of Biological Imaging, Central Institute for Translational Cancer Research (TranslaTUM), Technical University of Munich, Germany
| | - Guillermo J. Tearney
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114
| | - Vasilis Ntziachristos
- Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Neuherberg, Germany
- Chair of Biological Imaging, Central Institute for Translational Cancer Research (TranslaTUM), Technical University of Munich, Germany
| | - Farouc A. Jaffer
- Cardiovascular Research Center, Cardiology Division, Massachusetts General Hospital, Boston, MA 02114
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114
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Alfonso-Garcia A, Bec J, Weyers B, Marsden M, Zhou X, Li C, Marcu L. Mesoscopic fluorescence lifetime imaging: Fundamental principles, clinical applications and future directions. JOURNAL OF BIOPHOTONICS 2021; 14:e202000472. [PMID: 33710785 PMCID: PMC8579869 DOI: 10.1002/jbio.202000472] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 03/03/2021] [Accepted: 03/05/2021] [Indexed: 05/16/2023]
Abstract
Fluorescence lifetime imaging (FLIm) is an optical spectroscopic imaging technique capable of real-time assessments of tissue properties in clinical settings. Label-free FLIm is sensitive to changes in tissue structure and biochemistry resulting from pathological conditions, thus providing optical contrast to identify and monitor the progression of disease. Technical and methodological advances over the last two decades have enabled the development of FLIm instrumentation for real-time, in situ, mesoscopic imaging compatible with standard clinical workflows. Herein, we review the fundamental working principles of mesoscopic FLIm, discuss the technical characteristics of current clinical FLIm instrumentation, highlight the most commonly used analytical methods to interpret fluorescence lifetime data and discuss the recent applications of FLIm in surgical oncology and cardiovascular diagnostics. Finally, we conclude with an outlook on the future directions of clinical FLIm.
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Affiliation(s)
- Alba Alfonso-Garcia
- Department of Biomedical Engineering, University of California, Davis, Davis, California
| | - Julien Bec
- Department of Biomedical Engineering, University of California, Davis, Davis, California
| | - Brent Weyers
- Department of Biomedical Engineering, University of California, Davis, Davis, California
| | - Mark Marsden
- Department of Biomedical Engineering, University of California, Davis, Davis, California
| | - Xiangnan Zhou
- Department of Biomedical Engineering, University of California, Davis, Davis, California
| | - Cai Li
- Department of Biomedical Engineering, University of California, Davis, Davis, California
| | - Laura Marcu
- Department of Biomedical Engineering, University of California, Davis, Davis, California
- Department Neurological Surgery, University of California, Davis, California
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