Doppler ultrasound compatible plastic material for use in rigid flow models

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Materials Science

Background:

• Investigating carotid atherosclerosis requires accurate flow phantoms for Doppler ultrasound (DUS).
• Current methods for fabricating vascular flow phantoms can be time-consuming and lack geometric precision.
• A need exists for rapid and accurate methods to create flow phantoms with varied vascular geometries.

Purpose of the Study:

• To demonstrate the feasibility of using numerically controlled direct-machining to fabricate DUS-compatible plastic flow phantoms.
• To evaluate Teflon as a suitable material for creating carotid atherosclerosis flow models.
• To assess the accuracy and DUS compatibility of machined Teflon flow phantoms.

Main Methods:

• Candidate plastics were tested for speed of sound (SoS) and acoustic attenuation at 5 MHz.
• Teflon was selected based on its SoS and machinability.
• A carotid bifurcation flow model with eccentric stenosis was numerically machined into Teflon.
• Geometric accuracy was verified using micro-computed tomography.
• Doppler ultrasound data was acquired and compared with a tissue-mimicking phantom.

Main Results:

• Teflon exhibited an appropriate SoS (1376 m/s) for DUS applications, though with higher attenuation than other materials.
• Direct-machining produced a geometrically accurate carotid bifurcation phantom.
• Sufficient signal power was achieved in the Teflon phantom for Doppler data acquisition.
• Velocity profiles obtained in the Teflon phantom were comparable to those in tissue-mimicking phantoms.

Conclusions:

• Numerically controlled direct-machining is a feasible technique for fabricating DUS flow phantoms.
• Teflon offers a suitable combination of machinability and DUS compatibility for creating rigid flow models.
• This method facilitates the rapid and accurate production of vascular flow phantoms for atherosclerosis research.