Self-Expanding Spherical Tissue Marker for Stable Imaging
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Solution Overview
Problem
Existing implantable marking devices for tissue sites suffer from alignment-dependent visibility issues in imaging methods and are prone to migration or displacement after implantation, particularly in cases where tissue pressure is present.
Innovation Solution
A self-expanding, approximately spherical marking device with a woven or braided support structure made of metal wires, which expands against tissue pressure to ensure uniform visibility across different imaging modalities and prevents migration, filled with hydrogel to enhance ultrasound visibility and filled with hydrogel to maintain shape and visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a marking device is implanted via cannula into tissue, then it can mark the tissue site, but it may migrate or fall back into the cannula due to tissue pressure
Solution Approach 1:
The marking device transitions from a compressed delivery state to an expanded deployed state after implantation. The self-expanding support structure dynamically changes configuration to engage with tissue and prevent migration, while the hydrogel filler dynamically responds to tissue pressure to maintain positional stability.
Solution Approach 2:
The marking device is divided into distinct functional components: a support structure (woven/braided metal wires) that provides mechanical stability, and a hydrogel filler that provides pressure resistance and visibility. This segmentation allows each component to address specific aspects of the migration problem independently.
2Measurement precision
If the marking device is made visible for imaging diagnostics, then it can mark tissue sites, but visibility may be alignment-dependent
Solution Approach 1:
The support structure is configured to form an approximately spherical shape when expanded. This spherical geometry provides uniform visibility characteristics in imaging diagnostics regardless of the device's orientation or alignment, eliminating the alignment-dependent visibility problem.
Solution Approach 2:
The marking device combines metal wires (for structural integrity and X-ray visibility) with hydrogel (for ultrasound visibility and shape maintenance). This composite material approach ensures multi-modal imaging visibility that is independent of alignment, as each material contributes different visibility properties.
3Reliability
If the marking device expands against tissue pressure, then it prevents migration, but it increases interaction with adjacent tissue
Solution Approach 1:
The support structure is formed from flexible woven or braided metal wires that can conform to the tissue cavity shape. This flexibility allows the device to expand gently against tissue pressure to prevent migration while minimizing mechanical irritation and interaction with adjacent tissue structures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The marking device provides unambiguous visibility in various imaging methods and remains stable in tissue, minimizing migration risks and interaction with adjacent tissue, while allowing percutaneous implantation with minimal invasiveness.
Implementation Method 1
The support structure is formed by a multiplicity of metal wires and is elastic and compressible and self-expanding
Implementation Method 2
The support structure is formed from at least one wire, consisting of superelastic material, in particular of nitinol
Implementation Method 3
filled with hydrogel to enhance ultrasound visibility and filled with hydrogel to maintain shape and visibility
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3C
AI summary
Marking device (100) for implantation into a tissue (260), having a support structure (102) which is formed by at least one elastic metal wire or a slit tube (111), is compressible and is self-expanding and which, in an expanded state, encompasses an interior space wherein the marking device (100) is designed to transform itself on its own from a compressed state into an expanded state, even against a tissue pressure prevailing at a tissue site to be marked, and the marking device (100) in the expanded state has a hollow, approximately spherical shape.