Custom-made flow phantoms for quantitative ultrasound microvessel imaging

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Fluid Dynamics

Background:

• Morphologically realistic flow phantoms are crucial for validating quantitative ultrasound-based microvessel imaging.
• Developing advanced imaging tools necessitates more complex vessel-mimicking phantoms.

Purpose of the Study:

• To propose a novel method for fabricating sub-millimeter, morphologically complex vessel-mimicking phantoms.
• To evaluate different tissue-mimicking materials (TMMs) for their suitability in microflow imaging.

Main Methods:

• Fabrication of phantoms with sub-millimeter channels (0.15-1.25 mm) using metal wires and various TMMs (silicone rubber, plastisol, conventional gelatin, medical gelatin).
• Creation of bifurcations and complex geometries like branches and curvatures.
• Assessment of quantitative parameters and accuracy of measurements against ground truth.

Main Results:

• Medical gelatin emerged as the optimal TMM due to ease of fabrication, high transmittance, and acoustic properties similar to human tissue.
• Observed channel diameter increases (76-270%) in power Doppler images due to fluid pressure.
• Achieved physiological flow velocity (0.85 ± 0.01 mm/s) in the smallest medical gelatin phantom.

Conclusions:

• The developed method successfully fabricates complex, realistic microvessel phantoms using medical gelatin.
• These phantoms are suitable for validating quantitative ultrasound microvessel imaging techniques.
• The findings open new avenues for research in microvascular imaging and diagnostics.