TMS Electric Field Evaluation Using Precomputed Maps
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Solution Overview
Problem
Current TMS systems face challenges in accurately and efficiently determining the electric fields induced by electromagnetic coils due to the complexity of brain structure and tissue conductivity, leading to sub-optimal coil positioning and slow simulation times that hinder real-time adjustments in clinical settings.
Innovation Solution
A system and method that utilize a predetermined Magnetic Stimulation Profile (MSP) and Boundary Element Method with Fast Multilevel Multipole (BEM-FMM) to rapidly determine and visualize the electric fields induced by an electromagnetic coil, allowing for real-time adjustments and accurate targeting of brain regions by aligning the coil position and orientation with pre-calculated E-field maps and boundary models.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional E-field simulation methods are used to account for tissue conductivity boundaries, then measurement precision is improved, but computing time increases significantly
Solution Approach 1:
The patent pre-calculates and stores E-field maps and Magnetic Stimulation Profiles (MSP) for various coil positions and orientations before the actual TMS procedure. This preliminary computation allows the system to quickly retrieve and interpolate pre-computed data during real-time coil positioning, avoiding time-consuming simulations while maintaining accuracy.
Solution Approach 2:
The patent creates simplified boundary models that replicate the essential geometric and conductivity properties of the subject's head without full anatomical complexity. These boundary models are used to generate representative E-field maps that capture the key physical characteristics needed for accurate coil positioning, reducing computational requirements while preserving measurement precision.
2Manufacturing precision
If detailed boundary models accounting for tissue conductivity are used, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts only the essential geometric and conductivity boundary information needed for E-field calculation from full anatomical MRI data. This selective extraction creates simplified boundary models that retain the critical physical properties affecting E-field distribution while removing unnecessary anatomical detail, reducing system complexity while maintaining positioning accuracy.
Solution Approach 2:
The patent transforms complex anatomical data into simplified geometric parameters and conductivity values that define the boundary models. By changing the representation from detailed anatomical structures to essential physical parameters, the system achieves accurate coil positioning without the complexity of processing full anatomical models in real-time.
3Ease of operation
If real-time E-field visualization is implemented, then ease of operation is improved, but computing speed requirements increase
Solution Approach 1:
The patent pre-computes E-field maps and MSP for a comprehensive set of coil positions and orientations before the TMS procedure. During real-time operation, the system simply retrieves and interpolates from these pre-computed data structures, enabling instantaneous visualization and adjustment without demanding high real-time computation rates.
Solution Approach 2:
The patent implements a dynamic data structure that efficiently stores and retrieves E-field information for different coil positions and orientations. This dynamic organization allows the system to quickly access and update E-field visualizations as the coil moves, providing real-time feedback with minimal computational overhead.
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 ultra-fast computation and real-time visualization of electric fields, improving the accuracy of TMS coil positioning and enabling rapid adjustments, thus enhancing diagnostic and therapeutic outcomes in neuromodulation techniques.
Implementation Method 1
TMS uses magnetic fields to stimulate nerve cells in the brain of the subject. The magnetic fields are generated by an electromagnetic coil that is placed over the scalp of the subject to induce electric currents in the underlying brain tissue.
Implementation Method 2
The magnetic fields are generated by electric pulses applied to and flowing though the electromagnetic coil.
Data Source
AI summary
Systems, methods, and media for E-field determination are provided. In some embodiments, a method for E-field determination for an electromagnetic coil positioned about a subject having one or more conductivity boundaries comprises: retrieving a predetermined electromagnetic coil E-field map, boundary model, and Magnetic Stimulation Profile (MSP), wherein the MSP comprises the incident E-field at a surface of interest (Ainc) caused by a basis set of magnetic dipoles, and the total E-field at the surface of interest (Atot) caused by the basis set, receiving location information of the electromagnetic coil, aligning the boundary model with the electromagnetic coil map, determining the incident E-field (Einc) of the electromagnetic coil at the surface of interest, determining basis function coefficients (m) that Ainc to Ein<sup2>c </sup2>at the surface of interest, determining an approximation (Edtot) of the total E-field of the electromagnetic coil at the surface of interest, wherein: (Edtot)=Atotmî, and outputting the approximation.