Endovascular procedures have drastically improved the available therapy options for a number of diseases and conditions. Catheters can now be navigated deep into the body, including the brain, but there’s still room for improvement to traverse particularly tortuous vascular anatomy.
These days, most guidewires that are used to make the initial journey through the vasculature are pretty dumb. They can be rotated and pushed, and that’s about it, which can be pretty frustrating for the physicians who have to use them to get through three-dimensional mazes. There are externally steerable systems out there, such as those made by Stereotaxis, but they are only steerable at the tip and are not applicable within some of the narrower vessels in the brain.
Engineers at MIT have now developed a steerable guidewire that responds to a magnetic field through much of its length, and is narrow, slick, and flexible enough to work inside the brain.
Made from a nitinol core, a shape-memory alloy, it has a rubbery coating seeded with magnetic particles. The outside of the device is a thin hydrogel film that gives the guidewire a smoothness that makes it glide through blood vessels.
The guidewire can be pushed at the proximal end, while a hand-held magnet can help to steer it at the distal end near the tip.
To prove that the device can indeed move through challenging anatomy, a one-to-one model of a real patient’s brain vasculature, obtained from CT scans, was created. The vessels were filled with a fluid with the viscosity of blood and the guidewire was used to successfully navigate through these vessels.
Additionally, the team replaced the nitinol core of the guidewire with an optical fiber and demonstrated that light, including laser light, can also be delivered the same way to a potential treatment site.
Here’s an MIT video showing off the new steerable guidewire:
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