A novel catheter (IntelliCath, Intelligent Catheter Navigation) has been equipped with a special optical fibre containing tiny “mirrors”; these mirrors help operators see how a device moves through a patient’s vasculature, in 3D, during a procedure. Torben Pätz (Fraunhofer MEVIS, Bremen, Germany) and his co-developers have already tested the catheter’s feasibility.
According to a press release, the mirrors in the fibre reflect a portion of light when light passes through it. Whenever the fibre bends, the reflected light changes colour and sensors can then measure the change in colour. Additionally, live information from the fibre is fed into a 3D model—based on pre-procedural computed tomography (CT) or MR imaging—of the patient’s vasculature during an endovascular procedure. As a result, an operator can use the model to see how the device moves through the vascular labyrinth live and in 3D.
Talking about evaluating the feasibility of the catheter, Pätz comments: “We connected several silicone hoses into a curved labyrinth. Then, we inserted our device containing an optical fibre into the labyrinth.” On the monitor, he and his colleagues were able to locate the catheter’s position in real-time with precision approaching five millimetres. “The signal from the sensors gives us information about the intensity and direction of the curvature. To some extent, the fibre knows how it is formed,” Pätz adds. Pätz et al have already applied for two patents.
Although several medical device companies also work on similar projects, Pätz says, they have expended “a great deal of technical effort into trying to reconstruct the shape of the entire catheter, which can be up to two meters long”. “Our algorithm, however, only needs a fraction of the data to localise the catheter in a known vascular system,” he explains. The aim with their catheter is provide cost-effective technology without special fibres and measurement systems and, also, a system that is less sensitive to measurement errors than previous approaches.
Next, Pätz et al will test the IntelliCath system on both a full-body phantom of the human vascular system and a pig lung. Towards the end of the current project phase in 2020, a prototype will be ready to serve as a foundation for a clinical trial.
Furthermore, the investigators are developing acoustic feedback to relieve operators of the constant need to view at the monitor. The idea is to employ various indication sounds to signal how far the next vessel junction is and in which direction the catheter should be inserted. “It is similar to a car’s parking assistance system, where you also receive acoustic indications about the distance to the next obstacle,” Pätz states.
The press release reports that IntelliCath is a part of the SAFE (software support and assistance systems for minimally invasive neurovascular procedures) project. Its goal is to support physicians by facilitating X-ray navigation during catheter procedures. For example, software can display supplementary information extracted from CT or MR images into the live X-ray image. Additionally, artificial intelligence (AI) will be able to automatically detect the position of the catheter.
The project partners at the project group for Automation in Medicine and Biotechnology at the Fraunhofer Institute for Manufacturing Engineering and Automation IPA are developing an intelligent assistance system to support catheter procedures from support for manual navigation of the catheter to completely automatic navigation. SAFE is a Fraunhofer project with funding of 2.4 million euros. It commenced in April 2017 and will end in September 2020.