Translational Medical Device Lab, University of Galway, H91 TK33 Galway, Ireland.
Electrical and Electronic Engineering, University of Galway, H91 TK33 Galway, Ireland.
Sensors (Basel). 2024 May 17;24(10):3195. doi: 10.3390/s24103195.
Abdominal aortic aneurysm (AAA) is a dilation of the aorta artery larger than its normal diameter (>3 cm). Endovascular aneurysm repair (EVAR) is a minimally invasive treatment option that involves the placement of a graft in the aneurysmal portion of the aorta artery. This treatment requires multiple follow-ups with medical imaging, which is expensive, time-consuming, and resource-demanding for healthcare systems. An alternative solution is the use of wireless implantable sensors (WIMSs) to monitor the growth of the aneurysm. A WIMS capable of monitoring aneurysm size longitudinally could serve as an alternative monitoring approach for post-EVAR patients. This study has developed and characterised a three-coil inductive read-out system to detect variations in the resonance frequency of the novel Z-shaped WIMS implanted within the AAA sac. Specifically, the spacing between the transmitter and the repeater inductors was optimised to maximise the detection of the sensor by the transmitter inductor. Moreover, an experimental evaluation was also performed for different orientations of the transmitter coil with reference to the WIMS. Finally, the FDA-approved material nitinol was used to develop the WIMS, the transmitter, and repeater inductors as a proof of concept for further studies. The findings of the characterisation from the air medium suggest that the read-out system can detect the WIMS up to 5 cm, regardless of the orientation of the Z-shape WIMS, with the detection range increasing as the orientation approaches 0°. This study provides sufficient evidence that the proposed WIMS and the read-out system can be used for AAA expansion over time.
腹主动脉瘤 (AAA) 是指主动脉直径大于正常直径 (>3 厘米) 的扩张。血管内动脉瘤修复术 (EVAR) 是一种微创治疗选择，涉及在主动脉瘤部分放置移植物。这种治疗需要多次进行医学成像随访，这对医疗系统来说是昂贵、耗时和资源密集的。一种替代解决方案是使用无线植入式传感器 (WIMS) 来监测动脉瘤的生长。一种能够纵向监测动脉瘤大小的 WIMS 可以作为 EVAR 后患者的替代监测方法。本研究开发并表征了一种三线圈感应读出系统，用于检测植入 AAA 囊内的新型 Z 形 WIMS 共振频率的变化。具体来说，优化了发射器和中继器感应器之间的间距，以最大限度地提高感应器在发射器感应器中的检测效果。此外，还针对发射器线圈相对于 WIMS 的不同方向进行了实验评估。最后，使用经过 FDA 批准的材料镍钛诺来开发 WIMS、发射器和中继器感应器，作为进一步研究的概念验证。空气介质中的特性分析结果表明，无论 Z 形 WIMS 的方向如何，读取系统都可以检测到距离达 5 厘米的 WIMS，检测范围随着方向接近 0°而增加。本研究提供了充分的证据表明，所提出的 WIMS 和读取系统可用于随时间监测 AAA 的扩张。
