Adjustable MRI Tracking Device for Guidewire Localization
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Solution Overview
Problem
Existing MRI tracking devices for interventional instruments, such as guidewires and stents, cause signal loss and obscure anatomical details in MR images due to their magnetic susceptibility, making it difficult to accurately locate the device while visualizing surrounding tissues.
Innovation Solution
A tracking device with two or more members of different magnetic susceptibilities that can be adjusted between an 'on' and 'off' configuration, where the 'on' configuration produces a measurable local magnetic field and the 'off' configuration reduces this field, allowing for accurate device localization with minimal signal loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a paramagnetic indicator element is used to track the interventional device in MRI, then the device location can be determined, but signal loss occurs in the adjacent tissue region
Solution Approach 1:
The patent applies the dynamics principle by making the magnetic susceptibility of the indicator element adjustable through rotation. The indicator element can be rotated to different orientations relative to the MRI system's magnetic field, dynamically changing its magnetic susceptibility effect. When the indicator element is rotated to be perpendicular to the magnetic field, its magnetic susceptibility effect is minimized, thereby reducing signal loss in adjacent tissue while still allowing device tracking when oriented parallel to the field.
Solution Approach 2:
The patent implements parameter changes by altering the magnetic susceptibility of the indicator element through rotational movement. By changing the orientation parameter of the indicator element relative to the MRI magnetic field, the magnetic susceptibility effect is modulated. This allows the system to switch between states of high visibility (when parallel to field) and low signal interference (when perpendicular to field), resolving the contradiction between tracking accuracy and tissue signal preservation.
2Measurement precision
If the magnetic susceptibility of the indicator element is increased to improve device visibility, then tracking accuracy improves, but signal loss in adjacent tissue increases
Solution Approach 1:
The patent makes the magnetic susceptibility effect dynamic rather than static. The indicator element's orientation can be changed during the MRI procedure, allowing the magnetic susceptibility to be adjusted based on the specific imaging needs. When high tracking accuracy is required, the indicator is oriented parallel to the magnetic field; when tissue signal preservation is prioritized, it is rotated perpendicular to the field.
Solution Approach 2:
The patent changes the effective magnetic susceptibility parameter by rotating the indicator element. This parameter change allows the system to optimize between two extremes: maximum susceptibility for tracking accuracy and minimum susceptibility for tissue signal preservation. The rotational degree of freedom provides continuous control over the magnetic susceptibility effect.
3Measurement precision
If a paramagnetic marker is used to visualize the device tip, then the device can be located in MR images, but anatomical details in the vicinity are obscured
Solution Approach 1:
The patent applies dynamics by enabling rotational adjustment of the indicator element's orientation. This dynamic capability allows the operator to temporarily enhance device visibility by aligning the indicator parallel to the magnetic field for localization, then rotate it perpendicular to the field to preserve anatomical detail when precise localization is no longer needed. The system adapts its magnetic susceptibility effect based on the procedural stage.
Solution Approach 2:
The patent utilizes parameter changes through rotational movement to modulate the magnetic susceptibility of the indicator element. By changing the orientation parameter, the effective magnetic susceptibility is adjusted, allowing the system to switch between states that prioritize device localization and states that prioritize anatomical image quality in the region of interest.
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
Enables accurate tracking of interventional devices within MRI systems while minimizing signal distortion in adjacent tissues, improving diagnostic image quality by allowing visualization of both the device and surrounding anatomy.
Implementation Method 1
A tracking device with two or more members of different magnetic susceptibilities that can be adjusted between an 'on' and 'off' configuration, where the 'on' configuration produces a measurable local magnetic field
Implementation Method 2
the 'off' configuration reduces this field, allowing for accurate device localization with minimal signal loss
Data Source
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Figure 4~4A
AI summary
A tracking device configured to be coupled to an interventional instrument and tracked by a magnetic resonance imaging system is provided. The tracking device includes, for example, paramagnetic and diamagnetic components that form first and second tracking members. When the tracking device is adjusted into a first arrangement, the tracking device will produce a local magnetic field in the presence of the magnetic field of an MRI system that is measurable by the MRI system. However, when the tracking device is adjusted into a second arrangement, the local magnetic field produced by the tracking device is reduced relative to the first arrangement, wherein the reduced local magnetic field produces substantially no magnetic field disturbances detectable by the MRI system. Images may be acquired of a patient in which the tracking device has been introduced and, using a numerical fitting method, an accurate location of the tracking device can be determined.