Calibration-Free pTx of the Cervical, Thoracic, and Lumbar Spinal Cord at 7T

Motivation: Addressing the issue of lengthy parallel transmit (pTx) adjustment times caused by the absence of a dedicated spinal cord (SC) coil setting, which limits SC imaging at ultra-high field. Goal(s): Enhance imaging efficiency by universal shim modes that can be applied without the need for additional adjustment time for different SC regions and coils. Approach: We have built a library of channel-wise B1+ maps and optimized universal RF shims to optimize transmit homogeneity and efficiency. Results: The proposed universal shims significantly improve B1+ efficiency, achieving a 50% enhancement compared to the default shim mode, while eliminating the need for subject-specific pTx adjustments. Impact: The development of universal shims not only enhances SC imaging efficiency at ultra-high field but also streamlines the process by eliminating lengthy subject-specific pTx adjustments, expecting SC imaging to become more usable for non-pTx experts.