A MR compatible mechatronic system to facilitate magic angle experiments in vivo

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Orthopaedics

Background:

• The magic angle effect significantly increases MRI signal intensity in tendons and cartilage when oriented at 55 degrees to the main magnetic field (Bo).
• Clinical diagnosis of orthopaedic injuries benefits from understanding and utilizing this phenomenon.
• Previous experimental studies were limited by practical challenges in precisely orienting tissues within MRI scanners.

Purpose of the Study:

• To develop a novel MRI-compatible mechatronic system for precise positioning of limbs for diagnostic and research purposes.
• To overcome the limitations of manual tissue positioning in MRI studies of the magic angle effect.
• To facilitate better imaging of tendons and cartilage, aiding in the diagnosis of injuries.

Main Methods:

• Development of an MRI-compatible mechatronic system actuated by a novel pneumatic motor with a geared air turbine.
• Closed-loop control of the system using standard optical encoders for precise positioning.
• Testing the system's MR compatibility and performance through preliminary trials on human volunteers.

Main Results:

• The mechatronic system successfully positioned limbs within the MRI scanner's field of view.
• MR compatibility was demonstrated, showing no interference with imaging quality.
• Preliminary trials imaging the Achilles tendon showed a 4 to 13-fold increase in signal intensity at the magic angle orientation.

Conclusions:

• The developed mechatronic system is a viable tool for research and diagnosis in orthopaedics and related fields.
• Precise control over tissue orientation in MRI enhances the magic angle effect, leading to improved signal intensity.
• This technology has the potential to significantly advance the diagnostic accuracy of musculoskeletal injuries through MRI.