Transceiver 16-Channel Coaxial-End Dipole Array for Combined Head and C-Spine MRI at 9.4 T

Area of Science:

• Medical Imaging
• Biomedical Engineering
• Radiofrequency Engineering

Background:

• Current MRI technology faces limitations in simultaneously imaging the brain and cervical spine.
• Optimizing radiofrequency (RF) coil design is crucial for improving image quality and coverage in neuroimaging.

Purpose of the Study:

• To design and evaluate a novel double-row transceiver array for combined brain and cervical spine Magnetic Resonance Imaging (MRI).
• To optimize array geometry for enhanced transmit efficiency, B1+ field homogeneity, and safety (SAR).

Main Methods:

• Electromagnetic simulations were used to optimize a 16-element folded-end coaxial-end dipole array.
• The optimized array was constructed and tested using phantoms and healthy volunteers for anatomical imaging and transmit field mapping.
• Key performance metrics including transmit efficiency, B1+ homogeneity, and specific absorption rate (SAR) efficiency were evaluated.

Main Results:

• The designed array achieved RF excitation covering the entire brain and C-spine down to C7 (over 365 mm field of view).
• Excellent B1+ field homogeneity (~31% coefficient of variation) and mean transmit efficiency (~0.38 μT/√W) were measured.
• High SAR efficiency (~0.65 μT/√W/kg) was achieved in circularly polarized mode, ensuring patient safety.

Conclusions:

• The developed transceiver array effectively enables simultaneous high-quality imaging of the brain and cervical spine.
• This innovative coil design offers improved coverage and performance for comprehensive neuro-spinal MRI examinations.
• The findings support the clinical utility of this array for advanced diagnostic imaging of the central nervous system.