University of Pittsburgh and Virginia Commonwealth researchers have developed a stretchable, ultra-low profile wireless sensor using thin film nitinol (TFN). This sensor, with its ultra-low profile, is designed to be incorporated into an aneurysm coil or flow-diverting device and provide continuous monitoring of intra- and post-operative hemodynamic quiescence. Such wireless monitoring could allow for non-invasive continuous monitoring of blood flow within the aneurysm sac during and after surgical intervention.
A very-low profile (<1 mm) sensor has been developed to monitor hemodynamics around aneurysms. Produced using thin film nitinol (TFN), these sensors are biocompatible and can allow clinicians to monitor blood flow non-invasively to determine when intra-aneurysmal hemodynamic quiescence has been achieved, or if risk of aneurysm recurrence exists.
Description
When blood vessel walls weaken over time, localized enlargement of a blood vessel can form an aneurysmal sac. Rupturing of this sac can have devastating consequences, and mortality rates of up to 50% in cerebral aneurysms are reported. Endovascular embolization (EE) is a lower-risk treatment compared to an open craniotomy. In EE, a coil or flow-diverter is used to stop blood flow into the aneurysm. These techniques can fail leading to high recurrence rates which require long-term follow-up of patients, expensive imaging, invasive angiograms and increased patient anxiety. This wireless sensor could be an alternative approach to monitor aneurysm healing, improving patient outcomes.
Applications
• Intracranial aneurysm
• Carotid aneurysm
• Other neuroendovascular conditions
Advantages
While several wireless sensors are available for cardiovascular and aortic applications, their size makes them unsuitable for cerebral endovascular procedures which typically require microdelivery catheters. The need for any signal from a sensor to travel through thick tissue and skull is another challenge not met by existing technology.
This TFN sensor has an ultra-low profile and can be placed into an aneurysm or blood vessel along with endovascular devices during surgical intervention. Based on how blood flow can change the capacitance of a dialectic layer, these sensors can accurately detect blood flow and complete occlusion of an aneurysm.
Invention Readiness
Using micro-machine processes, flow sensors were produced using TFN and a dielectric elastomer. In vitro testing confirmed devices were hemocompatible. When used with a flow-divertor in vitro, the sensor could quantify intra-aneurysmal blood flow with a detection limit of 0.032 m/s. Further work is required to understand the long-term performance of the sensor and to develop wireless telemetry that would facilitate real-time continuous monitoring of hemodynamic quiescence.
IP Status
https://patents.google.com/patent/US11432731B2
