An electromagnetic actuator for brain magnetic resonance elastography with high frequency accuracy

Area of Science:

• Biomedical Engineering
• Medical Imaging Physics

Background:

• Magnetic Resonance Elastography (MRE) requires precise mechanical actuation to assess brain tissue stiffness.
• Existing actuators, such as pneumatic devices, can have limitations in accuracy, stability, and magnetic field interference.

Purpose of the Study:

• To design, test, and verify a novel electromagnetic actuator for brain MRE.
• To evaluate the actuator's performance in terms of magnetic field compatibility, vibration accuracy, and efficiency.

Main Methods:

• A grappler-shaped electromagnetic actuator was designed.
• Electromagnetic field simulations were performed to assess B0 field interference.
• Phantom and volunteer experiments were conducted to evaluate vibration spectra and MRE performance.

Main Results:

• The actuator exhibited a fringe field below 3 G, ensuring no interference with MRE imaging.
• Vibration analysis showed a significantly lower frequency offset and higher transmission efficiency compared to pneumatic devices.
• Brain MRE using the actuator yielded shear moduli consistent with literature values.

Conclusions:

• The developed electromagnetic actuator is suitable for multifrequency brain MRE with high accuracy.
• The actuator is user-friendly, patient-comfortable, portable, and offers superior performance to pneumatic alternatives.