MRI Catheter RF Tracking Coils for Radiation Reduction
Solution Overview
Problem
Conventional cardiac EP systems rely on X-ray imaging, which lacks the detailed tissue visualization and increased radiation exposure, necessitating the development of MRI-guided systems for more precise and safer cardiac ablation procedures.
Innovation Solution
An MRI-compatible ablation catheter with a flexible shaft, RF tracking coils, and a thermocouple, along with an MRI-guided interventional system that uses RF tracking coils to obtain real-time MRI images and track the catheter's position within the heart, allowing for precise articulation and visualization during procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If X-ray imaging is used for catheter guidance, then real-time visualization is achieved, but patient radiation exposure increases and tissue detail visualization is insufficient
Solution Approach 1:
The patent replaces X-ray imaging with MRI imaging for catheter guidance. MRI uses magnetic fields and radio waves instead of ionizing radiation, eliminating the harmful radiation effect while providing superior soft tissue contrast and detailed visualization of cardiac structures and ablation lesions.
Solution Approach 2:
The patent changes the imaging modality parameter from X-ray (ionizing radiation) to MRI (magnetic resonance), fundamentally altering the physical principles used for imaging. This parameter change eliminates radiation exposure while enhancing tissue detail visualization through MRI's superior soft tissue contrast capabilities.
2Object-affected harmful factors
If MRI imaging is used for catheter guidance, then patient radiation exposure is reduced and tissue detail visualization is improved, but device tracking capability is lost
Solution Approach 1:
The catheter is designed with multi-functionality: it combines ablation capability with MRI-compatible tracking features. The catheter includes MRI-visible materials and potentially embedded sensors that allow it to be both an effective ablation tool and a trackable object in the MRI environment, serving multiple functions simultaneously.
Solution Approach 2:
The patent introduces MRI-compatible tracking markers or fiducial markers as intermediaries. These markers are attached to or integrated with the catheter and are visible in MRI images, serving as mediators that enable catheter position tracking without requiring the catheter itself to be directly visible or emit signals in the MRI environment.
3Reliability
If conventional ablation catheters are used in MRI environment, then ablation function is maintained, but device heating and artifact generation occur
Solution Approach 1:
The catheter materials and design parameters are specifically modified for MRI compatibility. This includes using non-ferromagnetic materials, optimizing conductor geometries to minimize RF-induced heating, and designing electrode configurations that reduce artifact generation while maintaining ablation effectiveness.
Solution Approach 2:
The catheter employs composite materials that combine electrical conductivity for ablation with MRI compatibility. This may include using specific alloys or coatings that provide the necessary electrical properties for RF energy delivery while being non-magnetic and having low RF absorption characteristics to minimize heating and artifacts in the MRI environment.
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 precise placement of the ablation tip and reduces patient radiation exposure by providing detailed, real-time MRI images for guiding catheter placement and tissue ablation, enhancing the safety and effectiveness of cardiac ablation procedures.
Implementation Method 1
at least one RF tracking coil positioned adjacent the ablation tip and that includes a conductive lead, such as a coaxial cable, extending between the at least one, RF tracking coil and the electrical connector interface and configured to electrically connect the at least one tracking coil to an MRI scanner
Implementation Method 2
a thermocouple for measuring temperature
Data Source
AI summary
An MRI-compatible catheter includes an elongated flexible shaft having opposite distal and proximal end portions. A handle is attached to the proximal end portion and includes an actuator in communication with the shaft distal end portion that is configured to articulate the shaft distal end portion. The distal end portion of the shaft may include an ablation tip and includes at least one RF tracking coil positioned adjacent the ablation tip that is electrically connected to an MRI scanner. The at least one RF tracking coil is electrically connected to a circuit that reduces coupling when the at least one RF tracking coil is exposed to an MRI environment. Each RF tracking coil is a 1-10 turn solenoid coil, and has a length along the longitudinal direction of the catheter of between about 0.25 mm and about 4 mm.