A cone-shaped gradient coil design for high-resolution MRI head imaging

Area of Science:

• Magnetic Resonance Imaging (MRI) Physics
• Medical Device Engineering
• Biomedical Engineering

Background:

• Insertable head gradient coils offer superior gradient strength and switching speed compared to whole-body coils due to proximity to the target.
• Asymmetric configurations in head coils, while improving performance, present dimensional constraints and can induce patient claustrophobia.
• Current head coil designs face limitations in balancing performance with patient comfort and practical implementation.

Purpose of the Study:

• To propose and evaluate a novel cone-shaped model for asymmetric head gradient coils.
• To enhance gradient coil performance and mitigate patient claustrophobia.
• To explore the impact of conical tilting angles on coil efficiency and patient experience.

Main Methods:

• A cone-shaped coil model was designed with varying diameters to improve proximity to the head and accommodate patient anatomy.
• Two simulation cases were analyzed: Case I (fixed patient-end bore size) and Case II (fixed iso-center bore size).
• Performance was evaluated by comparing conical coils with different tilting angles against cylindrical counterparts.

Main Results:

• In Case I, a 14° tilting angle optimized performance, yielding 100%-200% improvement in transverse coil parameters and 50% in longitudinal coils compared to a 42 cm cylindrical coil.
• Conical coils generated less heat and acoustic noise.
• In Case II, a 14° conical coil showed 20%-50% transverse performance improvement but a 20%-40% decrease in longitudinal performance compared to a 34 cm cylindrical coil, while offering improved patient space.

Conclusions:

• The proposed cone-shaped gradient coil design offers significant performance improvements, particularly for transverse coils, and enhances patient comfort.
• Optimal performance is achieved at a 14° tilting angle, balancing gradient strength, speed, and patient-friendly design.
• This innovative design holds promise for advancing brain imaging techniques like functional MRI (fMRI).