Combined near-infrared fluorescent imaging and micro-computed tomography for directly visualizing cerebral thromboemboli

Dong Eog Kim, Jeong Yeon Kim, Su Kyoung Lee, Ju Hee Ryu, Ick Chan Kwon, Cheol Hee Ahn, Kwang Meyung Kim, Dawid Schellingerhout

Research output: Contribution to journalArticle

1 Citation (Scopus)

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.

Original languageEnglish
Article numbere54294
JournalJournal of Visualized Experiments
Volume2016
Issue number115
DOIs
Publication statusPublished - 2016 Sep 25
Externally publishedYes

Keywords

  • Cerebral infarction
  • Computed tomography
  • Embolic stroke
  • Gold nanoparticle
  • Issue 115
  • Medicine
  • MicroCT
  • Molecular imaging
  • Near-infrared fluorescent imaging
  • Thrombolysis
  • Thrombus imaging

ASJC Scopus subject areas

  • Neuroscience(all)
  • Chemical Engineering(all)
  • Immunology and Microbiology(all)
  • Biochemistry, Genetics and Molecular Biology(all)

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