title: Microsphere skimming in the porcine coronary arteries: Implications for flow quantification.
abstract: Particle skimming is a phenomenon where particles suspended in fluid flowing through vessels distribute disproportionately to bulk fluid volume at junctions. Microspheres are considered a gold standard of intra-organ perfusion measurements and are used widely in studies of flow distribution and quantification. It has previously been hypothesised that skimming at arterial junctions is responsible for a systematic over-estimation of myocardial perfusion from microspheres at the subendocardium. Our objective is to integrate coronary arterial structure and microsphere distribution, imaged at high resolution, to test the hypothesis of microsphere skimming in a porcine left coronary arterial (LCA) network. A detailed network was reconstructed from cryomicrotome imaging data and a Poiseuille flow model was used to simulate flow. A statistical approach using Clopper-Pearson confidence intervals was applied to determine the prevalence of skimming at bifurcations in the LCA. Results reveal that microsphere skimming is most prevalent at bifurcations in the larger coronary arteries, namely the epicardial and transmural arteries. Bifurcations at which skimming was identified have significantly more asymmetric branching parameters. This finding suggests that when using thin transmural segments to quantify flow from microspheres, a skimming-related deposition bias may result in underestimation of perfusion in the subepicardium, and overestimation in the subendocardium.
authors.affiliation: Division of Imaging Sciences and Biomedical Engineering, King's College London, British Heart Foundation (BHF) Centre of Excellence, UK; National Institute of Heath Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Lambeth Wing, St. Thomas' Hospital, UK; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, Lambeth Wing, St. Thomas' Hospital, London, UK.
authors.forename: Matthew
authors.initials: M
authors.lastname: Sinclair
authors.affiliation: Division of Imaging Sciences and Biomedical Engineering, King's College London, British Heart Foundation (BHF) Centre of Excellence, UK; National Institute of Heath Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Lambeth Wing, St. Thomas' Hospital, UK; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, Lambeth Wing, St. Thomas' Hospital, London, UK.
authors.forename: Jack
authors.initials: J
authors.lastname: Lee
authors.affiliation: Division of Imaging Sciences and Biomedical Engineering, King's College London, British Heart Foundation (BHF) Centre of Excellence, UK; National Institute of Heath Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Lambeth Wing, St. Thomas' Hospital, UK; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, Lambeth Wing, St. Thomas' Hospital, London, UK; Department of Cardiology and Pneumology, Georg-August-University, Göttingen, Germany; German Centre for Cardiovascular Research (DZHK, Partner Site Göttingen), Göttingen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Schuster
authors.affiliation: Division of Imaging Sciences and Biomedical Engineering, King's College London, British Heart Foundation (BHF) Centre of Excellence, UK; National Institute of Heath Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Lambeth Wing, St. Thomas' Hospital, UK; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, Lambeth Wing, St. Thomas' Hospital, London, UK.
authors.forename: Amedeo
authors.initials: A
authors.lastname: Chiribiri
authors.affiliation: Department of Biomedical Engineering & Physics, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: Jeroen
authors.initials: J
authors.lastname: van den Wijngaard
authors.affiliation: Department of Biomedical Engineering & Physics, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: Pepijn
authors.initials: P
authors.lastname: van Horssen
authors.affiliation: Department of Biomedical Engineering & Physics, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: Maria
authors.initials: M
authors.lastname: Siebes
authors.affiliation: Department of Biomedical Engineering & Physics, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: Jos A E
authors.initials: JA
authors.lastname: Spaan
authors.affiliation: Division of Imaging Sciences and Biomedical Engineering, King's College London, British Heart Foundation (BHF) Centre of Excellence, UK; National Institute of Heath Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Lambeth Wing, St. Thomas' Hospital, UK; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, Lambeth Wing, St. Thomas' Hospital, London, UK.
authors.forename: Eike
authors.initials: E
authors.lastname: Nagel
authors.affiliation: Division of Imaging Sciences and Biomedical Engineering, King's College London, British Heart Foundation (BHF) Centre of Excellence, UK; National Institute of Heath Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Lambeth Wing, St. Thomas' Hospital, UK; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, Lambeth Wing, St. Thomas' Hospital, London, UK; Department of Engineering, University of Auckland, Auckland, New Zealand. Electronic address: nicolas.smith@kcl.ac.uk.
authors.forename: Nicolas P
authors.initials: NP
authors.lastname: Smith
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D003198:Computer Simulation; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000033:anatomy & histology / Q000502:physiology*; D005456:Fluorescent Dyes / Q000008:administration & dosage*; D006439:Hemodynamics; D000067268:Isolated Heart Preparation; D008279:Magnetic Resonance Imaging; D008863:Microspheres; D008953:Models, Anatomic; D008955:Models, Cardiovascular; D055420:Perfusion Imaging / Q000379:methods; D011237:Predictive Value of Tests; D012039:Regional Blood Flow; D016628:Replica Techniques; D015203:Reproducibility of Results; D013552:Swine
chemical_list: D005456:Fluorescent Dyes
keywords: Coronary flow model; Microspheres; Perfusion quantification; Skimming