A Steady State T1rho-weighted Sequence for Breast MRI at Ultra-low Field (6.5 mT)

Motivation: Ultra-low field (ULF) MRI is a cost-effective and accessible technology, making it a promising option for breast cancer screening. T1rho, which reflects macromolecular dynamics, shows potential as a biomarker for identifying lesions. Implementing T1rho-weighted MRI at ultra-low fields could pave the way for non-contrast breast screening methods. Goal(s): To achieve T1rho-weighted breast MRI with high SNR and efficient scanning at ULF. Approach: We developed a sequence that incorporates a balanced spin-lock module within the bSSFP sequence to enable steady-state T1rho-weighted imaging. Results: The new steady state T1rho-weighted sequence has demonstrated the T1rho contribution to the contrast in phantom imaging, and in participant imaging. Impact: T1rho, reflecting macromolecular dynamics, is a valuable biomarker for tumor imaging. Our study aims to improve the performance of T1rho-weighted MRI at ultra-low field, providing a potential non-contrast approach for breast cancer screening.