title: Combined Near-infrared Fluorescent Imaging and Micro-computed Tomography for Directly Visualizing Cerebral Thromboemboli.
abstract: Direct thrombus imaging visualizes the root cause of thromboembolic infarction. Being able to image thrombus directly allows far better investigation of stroke than relying on indirect measurements, and will be a potent and robust vascular research tool. We use an optical imaging approach that labels thrombi with a molecular imaging thrombus marker - a Cy5.5 near-infrared fluorescent (NIRF) probe that is covalently linked to the fibrin strands of the thrombus by the fibrin-crosslinking enzymatic action of activated coagulation factor XIIIa during the process of clot maturation. A micro-computed tomography (microCT)-based approach uses thrombus-seeking gold nanoparticles (AuNPs) functionalized to target the major component of the clot: fibrin. This paper describes a detailed protocol for the combined in vivo microCT and ex vivo NIRF imaging of thromboemboli in a mouse model of embolic stroke. We show that in vivo microCT and fibrin-targeted glycol-chitosan AuNPs (fib-GC-AuNPs) can be used for visualizing both in situ thrombi and cerebral embolic thrombi. We also describe the use of in vivo microCT-based direct thrombus imaging to serially monitor the therapeutic effects of tissue plasminogen activator-mediated thrombolysis. After the last imaging session, we demonstrate by ex vivo NIRF imaging the extent and the distribution of residual thromboemboli in the brain. Finally, we describe quantitative image analyses of microCT and NIRF imaging data. The combined technique of direct thrombus imaging allows two independent methods of thrombus visualization to be compared: the area of thrombus-related fluorescent signal on ex vivo NIRF imaging vs. the volume of hyperdense microCT thrombi in vivo.
authors: Molecular Imaging and Neurovascular Research Laboratory, Dongguk University College of Medicine; kdongeog@duih.org.
authors: Dong-Eog
authors: DE
authors: Kim
authors: Molecular Imaging and Neurovascular Research Laboratory, Dongguk University College of Medicine.
authors: Jeong-Yeon
authors: JY
authors: Kim
authors: Molecular Imaging and Neurovascular Research Laboratory, Dongguk University College of Medicine.
authors: Su-Kyoung
authors: SK
authors: Lee
authors: Biomedical Research Center, Korea Institute of Science and Technology.
authors: Ju Hee
authors: JH
authors: Ryu
authors: Biomedical Research Center, Korea Institute of Science and Technology.
authors: Ick Chan
authors: IC
authors: Kwon
authors: Research Institute of Advanced Materials, Department of Materials Science and Engineering, Seoul National University.
authors: Cheol-Hee
authors: CH
authors: Ahn
authors: Biomedical Research Center, Korea Institute of Science and Technology.
authors: Kwangmeyung
authors: K
authors: Kim
authors: Departments of Radiology and Cancer Systems Imaging, University of Texas M.D. Anderson Cancer Center.
authors: Dawid
authors: D
authors: Schellingerhout
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D020767:Intracranial Thrombosis; D051379:Mice; D057054:Molecular Imaging; D013917:Thrombin; D013923:Thromboembolism; D013927:Thrombosis; D055114:X-Ray Microtomography
chemical_list: D013917:Thrombin