3D Printed Flow Phantoms With Fiducial Markers for Super-Resolution Ultrasound Imaging

The improved resolution provided by ultrasound super-resolution imaging (SRI) sets new demands on the fabrication of phantoms for the validation and verification of the technique. Phantoms should resemble tissue and replicate the 3D nature of tissue vasculature at the microvascular scale. This paper presents a potential method for creating complex 3D phantoms, via 3D printing of water-filled polymer networks. By using a custom-built stereolithographic printer, projected light of the desired patterns converts an aqueous poly(ethylene glycol) diacrylate (PEGDA) solution into a hydrogel, a material capable of containing 75 wt% of water. Due to the hydrogel mainly consisting of water, it will, from an acoustical point of view, respond very similar to tissue. A method for printing cavities as small as (100 μm)3 is demonstrated, and a 3D printed flow phantom containing channels with cross sections of (200 μm)2 is presented. The designed structures are geometrically manufactured with a 2% increase in dimensions. The potential for further reduction of the flow phantom channels size, makes 3D printing a promising method for obtaining microvascular-like structures.