A simple, realistic walled phantom for intravascular and intracardiac applications

Abstract

Purpose This work aims to develop a simple, anatomically and haptically realistic vascular phantom, compatible with intravascular and intracardiac ultrasound. The low-cost, dual-layered phantom bridges the gap between traditional wall-only and wall-less phantoms by showing both the vessel wall and surrounding tissue in ultrasound imaging. This phantom can better assist clinical tool training, testing of intravascular devices, blood flow studies, and validation of algorithms for intravascular and intracardiac surgical systems. Methods Polyvinyl alcohol cryogel (PVA-c) incorporating a scattering agent was used to obtain vessel and tissue-mimicking materials. Our specific design targeted the inferior vena cava and renal bifurcations which were modelled using CAD software. A custom mould and container were 3D-printed for shaping the desired vessel wall. Three phantoms were prepared by varying both the concentrations of scattering agent as well as the number of freeze–thaw cycles to which the phantom layers were subjected during the manufacturing process. Each phantom was evaluated using ultrasound imaging using the Foresight™ ICE probe. Geometrical validation was provided by comparing CAD design to a CT scan of the phantom. Results The desired vascular phantom was constructed using 2.5% and 0.05% scattering agent concentration in the vessel and tissue-mimicking layers, respectively. Imaging of the three phantoms showed that increasing the number of freeze–thaw cycles did not significantly enhance the image contrast. Comparison of the US images with their CT equivalents resulted in an average error of 0.9 for the lumen diameter. Conclusion The phantom is anatomically realistic when imaged with intracardiac ultrasound and provides a smooth lumen for the ultrasound probe and catheter to manoeuvre. The vascular phantom enables validation of intravascular and intracardiac image guidance systems. The simple construction technique also provides a workflow for designing complex, multi-layered arterial phantoms.

Development of Custom Wall-Less Cardiovascular Flow Phantoms with Tissue-Mimicking Gel

“…In general, walled flow phantoms present their own unique set of challenges such as increased difficulty in creating complex geometries and consistent wall thickness along with increased cost. 7 , 40 , 59 Additionally, this study utilized continuous flow whereas pulsatile flow is often desired for cardiovascular flow phantoms. Preliminary experimentation has qualitatively shown realistic mechanical reactions of the gel phantoms in response to pulsatile flow.…”

“… 9 , 11 , 19 , 24 , 51 , 53 , 54 Multiple studies have created phantoms by embedding a 3D print in various materials with subsequent removal to yield the desired geometry, most often producing wall-less phantoms, consisting of a tissue-mimicking block with a void or hollow lumen, as opposed to a walled phantom that has a thin, variable material thickness. 2 , 23 , 39 , 40 , 48 , 49 , 60 These wall-less phantoms are particularly useful in ultrasound-based imaging applications; however, the mechanical properties of the materials used are often not prioritized and thus their mimicry of human tissue in this regard is limited.…”

Toward Fluoro-Free Interventions: Using Radial Intracardiac Ultrasound for Vascular Navigation

“…A polyvinyl alcohol cryogel (PVA-C) vascular phantom was manufactured to imitate the infrarenal portion of the IVC (Nisar et al 2020). The phantom generated realistic US imaging when scanned with intravascular (IVUS) or intracardiac (ICE) US, thus displaying a vessel-mimicking layer, blood-mimicking fluid in the lumen and a surrounding tissue-mimicking layer.…”

“…As a visual validation, we determined what USbased navigation may look like. A tracked, straight-tip guidewire (Piazza et al 2020), augmented with a 5-DOF EM sensor, was maneuvered to navigate the vessels in the phantom.…”

Application of Binary Genetic Algorithm for Holographic Vascular Mimicking Phantom Reconstruction

“…He et al generated a breast phantom via three-dimensional (3D) printing and they used CT and MRI imaging modalities [12]. Nisar et al presented a vascular phantom and compared their model obtained by carrying out CAD software to the CT scan [13].…”