A technique for the rapid but accurate fabrication of multiple flow phantoms with variations in vascular geometry would be desirable in the investigation of carotid atherosclerosis. This study demonstrates the feasibility and efficacy of implementing numerically controlled direct-machining of vascular geometries into Doppler ultrasound (DUS)-compatible plastic for the easy fabrication of DUS flow phantoms. Candidate plastics were tested for longitudinal speed of sound (SoS) and acoustic attenuation at the diagnostic frequency of 5 MHz. Teflon® was found to have the most appropriate SoS (1376 ± 40 m s-1 compared with 1540 m s-1 in soft tissue) and thus was selected to construct a carotid bifurcation flow model with moderate eccentric stenosis. The vessel geometry was machined directly into Teflon® using a numerically controlled milling technique. Geometric accuracy of the phantom lumen was verified using nondestructive micro-computed tomography. Although Teflon® displayed a higher attenuation coefficient than other tested materials, Doppler data acquired in the Teflon® flow model indicated that sufficient signal power was delivered throughout the depth of the vessel and provided comparable velocity profiles to that obtained in the tissue-mimicking phantom. Our results indicate that Teflon® provides the best combination of machinability and DUS compatibility, making it an appropriate choice for the fabrication of rigid DUS flow models using a direct-machining method. (E-mail: email@example.com).
|Number of pages
|Ultrasound in Medicine and Biology
|Published - Nov 2008
Bibliographical noteFunding Information:
We acknowledge ATL (Advanced Technology Laboratories, Philips, Seattle, WA, USA) for the UM9 ultrasound unit. Financial support has been provided by the Heart and Stroke Foundation of Ontario (grant #T-5135). Vessel models were fabricated with support from the Canadian Institutes for Health Research (group grant #GR-14973). Dr. Holdsworth is a Career Investigator, supported by the Heart and Stroke Foundation of Ontario. Dr. Poepping is supported by a University Faculty Award given by the Natural Sciences and Engineering Research Council of Canada.
- Acoustic attenuation
- Blood flow velocity
- Carotid artery
- Doppler ultrasound
- Flow model
- Speed of sound