Self-Expanding Tissue Marker Structure for Stable Multi-Modal Imaging
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Solution Overview
Problem
Existing marking devices for tissue sites have issues with visibility in various imaging methods and can migrate or be dislodged post-implantation, particularly in biopsy sites, due to their alignment-dependent visibility and shape.
Innovation Solution
A self-expanding, compressible marking device with a support structure formed by elastic metal or plastic wires, designed to assume a spherical shape, ensuring visibility across different imaging methods and preventing migration by expanding against tissue pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a marking device is designed with a fixed shape and size, then it can be easily manufactured and implanted, but it cannot adapt to different tissue pressures and may migrate or be dislodged post-implantation
Solution Approach 1:
The marking device employs a self-expanding support structure that transitions from a compressed delivery state to an expanded marking state. The support structure includes expandable elements such as a spherical cage or mesh framework that automatically expands upon release from the delivery catheter, adapting to the surrounding tissue pressure and preventing migration. This dynamic transformation resolves the contradiction by providing stability in tissue without requiring complex active control mechanisms.
Solution Approach 2:
The marking device utilizes material properties and geometric parameters that enable automatic expansion. The support structure is designed with specific dimensional ratios and material elasticity characteristics that cause it to expand from a compressed state to a larger marking state upon release. This parameter-based self-expansion allows the device to adapt to tissue pressure and maintain stability without complex control systems.
2Difficulty of detecting and measuring
If a marking device has alignment-dependent visibility, then it can be simplified in structure, but it becomes difficult to detect in imaging methods when not properly aligned
Solution Approach 1:
The marking device incorporates a spherical or radially symmetric support structure that provides uniform visibility in multiple imaging planes. The spherical cage or mesh framework ensures that the marking device can be detected consistently regardless of its orientation relative to the imaging beam, eliminating alignment-dependent visibility issues. This geometric choice resolves the contradiction by providing reliable detection without requiring complex active orientation mechanisms.
3Ease of operation
If a marking device is implanted in a compressed state through a catheter, then it can be delivered through small incisions, but it must transform itself against tissue pressure to achieve proper marking
Solution Approach 1:
The marking device is pre-compressed into a delivery catheter in a controlled manner during manufacturing. The support structure is designed with predetermined expansion characteristics that enable it to transform from the compressed delivery state to the expanded marking state upon release. This preliminary compression allows delivery through small incisions while the built-in expansion mechanism provides sufficient force to overcome tissue pressure and maintain proper marking geometry.
4Duration of action of stationary object
If a marking device remains permanently in tissue, then it provides long-term marking capability, but it may cause chronic tissue interaction or degradation
Solution Approach 1:
The marking device utilizes a porous or mesh-like support structure that allows tissue ingrowth and fluid permeation. The porous cage or mesh framework provides long-term structural stability for marking while allowing the tissue to interact with the device in a benign manner, preventing chronic inflammation or harmful tissue reactions. The porosity enables the device to remain permanently in tissue without causing excessive tissue interaction or degradation.
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 ultrasound, X-ray, and MRI imaging, while minimizing migration and displacement, ensuring long-term marking without degrading and causing tissue interaction.
Implementation Method 1
The marking device 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
Implementation Method 2
The support structure is self-expanding and can transform itself from a compressed state into an expanded state
Data Source
AI summary
A marking device comprises a support structure configured to transition between radially compressed and axially compressed states. The support structure comprises a plurality of substantially rectangular segments bounded by first and second tubular ends extending along a longitudinal axis of the marking device and each having a first end and a second end. At least one of the first ends and the second ends terminates at one of the first and second tubular ends. When the support structure is in the radially compressed state, the plurality of segments extend substantially parallel to one another along the longitudinal axis of the marking device. And, when the support structure is in the axially compressed state, at least a portion of the plurality of segments flair radially outward such that a central portion of the support structure has a curved shape encompassing an interior space bounded by the first and second tubular ends.