MRI Stylet with Recessed Conductor Loops for Signal Resolution
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Solution Overview
Problem
There is a need for alternative MRI-compatible configurations and designs suitable for MRI-guided surgical procedures, particularly for intrabody imaging and deep brain or cardiac interventions, as existing technologies do not adequately address the requirement for high-resolution signal acquisition and tissue imaging.
Innovation Solution
The development of MRI-compatible stylets with a rigid non-ferromagnetic body featuring longitudinally extending recessed surfaces and transversely spaced apertures, which include conductors forming external loops to act as MRI antennas, connected to a coaxial cable and tuned with capacitors for optimal signal reception, along with RF decoupling and matching circuits for safe operation during MRI procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional MRI-compatible configurations are used, then basic MRI imaging is possible, but high-resolution signal acquisition and real-time tissue imaging are not achieved
Solution Approach 1:
The MRI antenna is segmented into multiple discrete loops (first loop, second loop, third loop) arranged along the stylet body. Each loop can be independently configured and positioned, allowing the system to achieve high-resolution signal acquisition through multiple spatial sampling points while maintaining manageable device complexity through modular design
Solution Approach 2:
The patent transitions from conventional single-plane or simple coil configurations to a three-dimensional arrangement of multiple loops around the cylindrical stylet body. The loops are positioned at different angular positions (e.g., 0 degrees, 90 degrees, 180 degrees) and distances from the stylet surface, creating a volumetric antenna array that captures MRI signals from multiple spatial dimensions, thereby achieving high-resolution imaging
2Measurement precision
If multiple external loops are added to improve signal reception, then MRI image resolution improves, but device complexity increases
Solution Approach 1:
The stylet body serves multiple functions: it provides structural support, defines the geometric configuration for multiple conductor loops, and acts as a non-ferromagnetic core that maintains loop positions. The conductor itself serves dual purposes by forming both the MRI antenna loops and potentially serving as electrical leads for other functions, reducing overall device complexity
Solution Approach 2:
Multiple conductor loops are merged into a single integrated antenna system that operates cooperatively during MRI procedures. The loops are electrically connected through the conductor, which extends from one loop through the stylet body to other loops, creating a unified multi-element antenna array that improves signal reception without requiring separate independent components
3Measurement precision
If the stylet body is made rigid for structural stability, then positioning accuracy improves, but flexibility for intrabody navigation is reduced
Solution Approach 1:
The stylet is divided into segments with different mechanical properties: a rigid stylet body portion that provides stable positioning and antenna support, and a flexible distal portion or tip that can navigate tortuous intrabody pathways. This segmentation allows the device to combine the positioning accuracy of rigid structures with the navigation flexibility of flexible components
Solution Approach 2:
The stylet body is constructed from composite materials or material combinations that provide both rigidity and flexibility. The proximal portion uses rigid non-ferromagnetic materials (such as ceramic or rigid polymer) for structural stability and antenna mounting, while the distal portion incorporates flexible materials that allow bending and navigation through body cavities, achieving both positioning accuracy and navigation versatility
4Measurement precision
If the conductor loops are positioned close to the stylet body surface, then signal reception efficiency improves, but the risk of RF heating and interference increases
Solution Approach 1:
Different regions of the stylet body have different loop configurations and spacing. In regions where signal reception is critical and tissue access is limited, loops are positioned closer to the surface. In regions where RF heating risk is higher or tissue accessibility is better, loops are positioned farther away or spaced more densely. This local optimization allows the system to maximize signal reception efficiency while minimizing RF heating risks in different anatomical locations
Solution Approach 2:
The antenna system incorporates adjustable or reconfigurable loop positions and configurations that can be dynamically optimized during the procedure. The conductor loops can be repositioned along the stylet body to adjust the distance from the tissue surface, allowing the operator to balance signal reception efficiency against RF heating risk based on real-time procedural requirements and tissue characteristics
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
These stylets enable high-resolution MRI imaging and real-time signal detection within the body, facilitating precise diagnostic and interventional procedures by providing effective MRI signal reception and isolation during RF transmissions, thus enhancing the accuracy and safety of MRI-guided surgeries.
Implementation Method 1
the at least one conductor with the at least one loop is configured to act as an MRI antenna
Data Source
AI summary
Intrabody MRI-compatible medical devices with a rigid stylet body with opposing distal and proximal ends with a wall enclosing at least one cavity extending therebetween. The stylet body has first and second laterally spaced apart and opposing external longitudinally extending recessed surfaces and at least one pair of transversely spaced apart apertures extending through the wall and at least one conductor having a length that extends through the cavity then exits the cavity to define at least one external loop extending between the distal end of the stylet body and the pair of transversely spaced apart apertures. First and second legs of each loop snugly abut a respective first and second recessed surface of the stylet body to thereby cooperate with the stylet body to define a substantially cylindrical shape. The at least one conductor with the at least one loop is configured to act as an MRI antenna.