Three-Axis Coil Covering for Accurate MEG/MRI Registration
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Solution Overview
Problem
The registration and fusion of magnetoencephalography (MEG) and magnetic resonance imaging (MRI) data are sources of bias, degrading the accuracy of functional localization in biomagnetic imaging.
Innovation Solution
A device comprising an envelope with markers and three-axis coils positioned on specific points of the patient's body, allowing for precise co-localization and self-referencing of optically pumped magnetometers during both biomagnetic and MRI examinations, facilitating the merging of MEG/MRI or MCG/MRI data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a two-step registration and fusion procedure is used to combine MEG and MRI data, then the imaging process can be completed, but registration and fusion biases are introduced that degrade the accuracy of functional localization
Solution Approach 1:
The patent applies preliminary action by pre-positioning co-localized markers and three-axis coils on the patient's head before both MEG and MRI examinations. This ensures that the reference points are established in advance, eliminating the need for subsequent registration and fusion operations that introduce biases. The markers and coils are fixed together on a support structure, guaranteeing their relative positions are maintained throughout both imaging procedures.
Solution Approach 2:
The patent introduces markers and three-axis coils as intermediary elements that serve as common reference points for both MEG and MRI systems. These intermediaries are visible to both imaging modalities and provide a bridge between the two coordinate systems, enabling direct co-registration without complex fusion algorithms that introduce errors.
2Measurement precision
If external optical or electromagnetic systems are used to locate singular points during MEG data acquisition, then the position of MEG sensors can be registered relative to the patient's head, but additional complexity and potential sources of error are introduced
Solution Approach 1:
The patent applies self-service by enabling the MEG system to automatically locate reference points using the magnetic fields emitted by the three-axis coils attached to the patient's head. The optically pumped magnetometers in the MEG system detect the magnetic signatures of the coils, allowing the system to self-register its sensor positions relative to the patient's anatomy without requiring external optical or electromagnetic tracking systems.
Solution Approach 2:
The patent replaces mechanical and optical external tracking systems with a magnetic field-based self-localization method. Instead of using external optical cameras or electromagnetic trackers to locate singular points, the system uses the intrinsic magnetic fields emitted by the three-axis coils on the patient's head, which are detected by the MEG's optically pumped magnetometers.
3Reliability
If SQUID sensors are positioned a few centimeters from the patient's head using cryogenic fluid, then the sensors can be cooled and operated, but the distance degrades the quality of the measured signal
Solution Approach 1:
The patent uses a flexible envelope or helmet structure made of non-magnetic material that can be positioned directly on the patient's head. This flexible shell holds the cooled SQUID sensors in close proximity to the scalp while maintaining the cryogenic environment, thereby minimizing the distance between sensors and neural sources without compromising sensor cooling or patient comfort.
4Ease of operation
If the patient's head moves relative to fixed SQUID sensors, then the examination can proceed, but the accuracy of the MEG imaging is compromised
Solution Approach 1:
The patent applies dynamics by making the entire sensor array movable relative to the patient's head. The helmet or envelope containing the SQUID sensors can be adjusted and repositioned to maintain optimal alignment with the patient's anatomical landmarks throughout the examination. This dynamic adjustment capability allows the system to compensate for head movements and maintain imaging accuracy without requiring the patient to remain perfectly still.
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 highly accurate combined medical imaging by eliminating registration and fusion biases, ensuring precise alignment of MEG/MRI or MCG/MRI data without the need for external systems, thus improving the accuracy of biomagnetic image registration.
Implementation Method 1
at least five three-axis coils, each three-axis coil being adapted to emit a magnetic field, the magnetic fields of said three-axis coils being detectable by an array of optically pumped magnetometers during a biomagnetic imaging examination
Implementation Method 2
said markers being adapted to create contrast when an image of the patient is acquired by magnetic resonance imaging
Implementation Method 3
The principle of MRI is based on the phenomenon of nuclear magnetic resonance, which involves the coupling between the magnetic moment of an atomic nucleus and an external magnetic field
Implementation Method 4
The protrusion acts as a guide for positioning the three-axis coil within the support
Data Source
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AI summary
The invention relates to a device for improving the precision of a biomagnetic image of a patient. The device comprises a covering (101), a plurality of markers (102, 102A, 102B, 102C, 102D, 102E) and at least five three-axis coils (103A, 103B, 103C, 103D, 103E). Three-axis coils (103A, 103B, 103C, 103D, 103E) and markers of the plurality of markers (102A, 102B, 102C, 102D, 102E) are placed at the same location on the covering (101) so that, when the covering (101) is positioned on the patient, singular points of the part of the patient can be detected by magnetic resonance imaging and by biomagnetic imaging (MEG, MCG).