Helical toroid phantom for 3D flow imaging investigations.

Area of Science:

• Medical Physics
• Biomedical Engineering
• Fluid Dynamics

Background:

• Existing calibration phantoms do not adequately assess three-dimensional (3D) flow imaging performance.
• There is a need for a tool that can holistically evaluate complex flow patterns.

Purpose of the Study:

• To design and fabricate a novel omnidirectional, three-component (3-C) flow phantom.
• To validate the phantom's ability to mimic complex flow trajectories using computational fluid dynamics (CFD) and ultrasound.

Main Methods:

• A helical toroid lumen structure was designed and fabricated using polyvinyl alcohol cryogel (PVA).
• Computational fluid dynamics (CFD) simulations were used to model flow patterns.
• 3D ultrasound and pulsed Doppler measurements were employed for validation.

Main Results:

• The phantom's helical toroid geometry was confirmed by 3D ultrasound.
• Flow velocity magnitudes and vectors from pulsed Doppler measurements showed good agreement with CFD simulations (<7% difference in magnitude, 10° in angle).
• Ultrasound color flow imaging demonstrated alignment between the phantom's axial flow and CFD profiles.

Conclusions:

• The developed helical toroid phantom serves as an effective calibration tool for 3D flow imaging.
• This phantom has significant potential for advancing flow vector estimation and visualization algorithms in medical imaging.