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\({\,\mathrm{mm}}\) 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.

中文翻译：

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一种用于血管内和心内应用的简单、逼真的有壁模型。

目的

这项工作旨在开发一种简单、解剖学和触觉逼真的血管幻影，与血管内和心内超声兼容。低成本的双层体模通过在超声成像中同时显示血管壁和周围组织，弥合了传统仅壁体模和无壁体模之间的差距。该体模可以更好地辅助临床工具培训、血管内设备测试、血流研究以及血管内和心内外科系统算法的验证。

方法

掺入散射剂的聚乙烯醇冷冻凝胶 (PVA-c) 用于获得血管和组织模拟材料。我们的具体设计针对使用 CAD 软件建模的下腔静脉和肾分叉。定制的模具和容器经过 3D 打印，用于塑造所需的血管壁。通过改变散射剂的浓度以及在制造过程中幻影层经受的冻融循环次数，制备了三个幻影。使用 Foresight™ ICE 探头使用超声成像对每个体模进行评估。通过将 CAD 设计与体模的 CT 扫描进行比较来提供几何验证。

结果

分别在血管和组织模拟层中使用 2.5% 和 0.05% 的散射剂浓度构建所需的血管模型。三个体模的成像表明，增加冻融循环次数并没有显着提高图像对比度。US 图像与其 CT 等效图像的​​比较导致管腔直径的平均误差为 0.9 \({\,\mathrm{mm}}\)。

结论

当使用心内超声成像时，该体模在解剖学上是逼真的，并为超声探头和导管提供了一个平滑的管腔以进行操作。血管模型能够验证血管内和心内图像引导系统。简单的构建技术还为设计复杂的多层动脉模型提供了工作流程。