title: Porcine In Vivo Validation of a Virtual Contrast Model: The Influence of Contrast Agent Properties and Vessel Flow Rates.
abstract: Accurately and efficiently modeling the transport of angiographic contrast currently offers the best method of verifying computational fluid dynamics simulations and, with it, progress toward the lofty goal of prediction of aneurysm treatment outcome a priori. This study specifically examines the influence of estimated flow rate and contrast properties on such in silico predictions of aneurysm contrast residence and decay.
  
  
  
  Four experimental sidewall aneurysms were created in swine, with aneurysm contrast flow patterns and decay rates observed under angiography. A simplified computational fluid dynamics model of the experimental aneurysm was constructed from 3D angiography and contrast residence predicted a priori. The relative influence of a number of estimated model parameters (contrast viscosity, contrast density, and blood flow rate) on contrast residence was then investigated with further simulations.
  
  
  
  Contrast infiltration and washout pattern were accurately predicted by the a priori computational fluid dynamics model; however, the contrast decay rate was underestimated by ∼25%. This error was attributed to the estimated parent vessel flow rate alone, and the effects of contrast viscosity and density on the decay rate were found to be inconsequential. A linear correlation between the parent vessel flow rate and the corresponding contrast decay rate was observed.
  
  
  
  In experimental sidewall aneurysms, contrast fluid properties (viscosity and density) were shown to have a negligible effect on variation in the modeled contrast decay rate. A strong linear correlation was observed between parent vessel flow rate and contrast decay over a physiologically reasonable range of flow rates.
authors.affiliation: From the Department of Mechanical Engineering (T.W.P., Y.V.), University College London, London, UK.
authors.forename: T W
authors.identifier: 0000-0002-8774-519X
authors.initials: TW
authors.lastname: Peach
authors.affiliation: From the Department of Mechanical Engineering (T.W.P., Y.V.), University College London, London, UK y.ventikos@ucl.ac.uk.
authors.forename: Y
authors.identifier: 0000-0002-8589-8117
authors.initials: Y
authors.lastname: Ventikos
authors.affiliation: Department of Neuroradiology (J.V.B.), John Radcliffe Hospital, Oxford, UK.
authors.forename: J V
authors.identifier: 0000-0002-1268-3000
authors.initials: JV
authors.lastname: Byrne
authors.affiliation: Department of Engineering Science (Z.Y.), University of Oxford, Oxford, UK.
authors.forename: Z
authors.identifier: 0000-0002-5286-7218
authors.initials: Z
authors.lastname: You
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity / Q000502:physiology*; D002533:Cerebral Angiography / Q000379:methods*; D003198:Computer Simulation; D003287:Contrast Media; D006801:Humans; D057446:Hydrodynamics; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging*; D008955:Models, Cardiovascular; D013552:Swine
chemical_list: D003287:Contrast Media