Fabrication of rigid and flexible refractive-index-matched flow phantoms for flow visualisation and optical flow measurements

P. H. Geoghegan, N. A. Buchmann, C. J.T. Spence, S. Moore, Mark C. Jermy

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Abstract

A method for the construction of both rigid and compliant (flexible) transparent flow phantoms of biological flow structures, suitable for PIV and other optical flow methods with refractive-index-matched working fluid is described in detail. Methods for matching the in vivo compliance and elastic wave propagation wavelength are presented. The manipulation of MRI and CT scan data through an investment casting mould is described. A method for the casting of bubble-free phantoms in silicone elastomer is given. The method is applied to fabricate flexible phantoms of the carotid artery (with and without stenosis), the carotid artery bifurcation (idealised and patient-specific) and the human upper airway (nasal cavity). The fidelity of the phantoms to the original scan data is measured, and it is shown that the cross-sectional error is less than 5% for phantoms of simple shape but up to 16% for complex cross-sectional shapes such as the nasal cavity. This error is mainly due to the application of a PVA coating to the inner mould and can be reduced by shrinking the digital model. Sixteen per cent variation in area is less than the natural patient to patient variation of the physiological geometries. The compliance of the phantom walls is controlled within physiologically realistic ranges, by choice of the wall thickness, transmural pressure and Young's modulus of the elastomer. Data for the dependence of Young's modulus on curing temperature are given for Sylgard 184. Data for the temperature dependence of density, viscosity and refractive index of the refractiveindex- matched working liquid (i.e. water-glycerol mixtures) are also presented.

Original languageEnglish
Pages (from-to)1331-1347
Number of pages17
JournalExperiments in Fluids
Volume52
Issue number5
DOIs
Publication statusPublished - May 2012

Keywords

  • Particle Image Velocimetry
  • Nasal Cavity
  • Digital Model
  • Silicone Elastomer
  • Medical Imaging Data

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  • Research Output

    • 7 Article
    • 1 Conference contribution

    A Review of Arterial Phantom Fabrication Methods for Flow Measurement Using PIV Techniques

    Yazdi, S. G., Geoghegan, P. H., Docherty, P. D., Jermy, M. & Khanafer, A., 9 Jul 2018, In : Annals of Biomedical Engineering.

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  • A PIV comparison of the flow field and wall shear stress in rigid and compliant models of healthy carotid arteries

    Geoghegan, P. H., Jermy, M. C. & Nobes, D. S., 21 Jul 2017, In : Journal of Mechanics in Medicine and Biology. 17, 3, 1750041.

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    Open Access
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  • Regressive cross-correlation of pressure signals in the region of stenosis: Insights from particle image velocimetry experimentation

    Docherty, P. D., Geoghegan, P. H., Huetter, L., Jermy, M. & Sellier, M., 1 Feb 2017, In : Biomedical Signal Processing and Control. 32, p. 143-149 7 p.

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