Cobalt Oxide Anti-Artifact Layer for MRI Medical Devices
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Solution Overview
Problem
Conventional metallic medical devices, such as stents, cause artifacts in MRI due to their ferro- or ferri-magnetic properties, which can obstruct image visibility, especially when made from cobalt-based alloys lacking sufficient nickel content or exhibiting FFM properties in their oxidized state, where conventional anti-artifact methods are ineffective.
Innovation Solution
A cobalt-rich composition is applied as an anti-artifact layer on the metallic substrate, with at least 50% cobalt atomic percent in the oxide layer, where at least 90% of cobalt atoms are oxidized into Co(II) and Co(III) states, effectively reducing MRI artifacts by forming a thick cobalt oxide layer, particularly using physical vapor deposition and thermal treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metallic substrate with FFM properties is used to ensure adequate mechanical properties, then mechanical strength is improved, but MRI artifact production increases
Solution Approach 1:
An anti-artifact layer is introduced as an intermediary between the FFM metallic substrate and the MRI imaging process. This layer contains FFM materials in oxidized state that mask the magnetic properties of the underlying metal, reducing artifact production while preserving the mechanical integrity of the device
Solution Approach 2:
The medical device is constructed as a composite structure with a metallic substrate providing mechanical strength and an anti-artifact layer providing MRI compatibility. The anti-artifact layer itself is a composite of FFM materials in oxidized state, combining multiple materials to achieve both mechanical support and artifact reduction
2Reliability
If conventional anti-artifact methods are used on cobalt-based alloys with insufficient nickel content, then MRI compatibility is attempted to be improved, but the methods become ineffective
Solution Approach 1:
The invention changes the chemical state parameter of FFM materials from metallic to oxidized state. By oxidizing metals like chromium and iron in the alloy, the method creates an anti-artifact effect without requiring nickel, thus expanding applicability to cobalt-based alloys with insufficient nickel content
Solution Approach 2:
Instead of using non-FFM materials or reducing FFM content to improve MRI compatibility, the invention inverts the approach by utilizing FFM materials in oxidized state. This oxidation-based approach works effectively on cobalt-based alloys regardless of nickel content, making the method universally applicable
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 cobalt-rich anti-artifact layer significantly reduces MRI artifacts, enhancing the visibility of tissues and structures around and within medical devices, such as stents, by masking the ferro- or ferri-magnetic properties of the substrate, thereby improving imaging quality.
Implementation Method 1
physical vapor deposition
Implementation Method 2
at least 90% of cobalt atoms are oxidized into Co(II) and Co(III) states
Implementation Method 3
thermal treatment
Data Source
AI summary
Cobalt in oxidized state for use as anti-artifact layer (4) covering a metallic substrate (1) of a medical device for reducing the production of artifacts in MRI caused by the magnetic property of the (1), wherein the anti-artifact layer (4) is present at outermost surface of the metallic substrate (1) and has at least 30% of cobalt ratio (at % Co) to the total amount of transition metallic atoms present therein, and at least 90% of cobalt atoms present within the anti-artifact layer (4) are converted into at least one of Co(II) oxidized state and Co(III) oxidized state.