Transient-state CSF suppression for time-efficient, high-resolution 3T whole-brain 3D relaxometry

Motivation: Cerebrospinal fluid (CSF) pulsation artifacts using 3D unbalanced gradient-echo sequences hinder the accuracy of whole-brain relaxometry measurements. Goal(s): To develop a CSF-suppressed 3D MR-STAT sequence and eliminate CSF pulsation artifacts, allowing for fast, high-resolution whole-brain relaxometry with enhanced image quality. Approach: The time-varying RF flip-angle train is optimized with an additional CSF suppression constraint to achieve both high quantitative parameter encoding capability and low CSF signal intensity. Results: The new CSF-suppressed 3D MR-STAT sequence has been validated on healthy volunteers, demonstrating effective mitigation of CSF ghosting artifacts, and allowing whole-brain relaxometry acquisition within 5.5-minute scan time. Impact: The proposed MR-STAT sequence with CSF suppression requires a short scan time (less than 6 minutes) and shows robustness in whole-brain 1mm3 isotropic relaxometry, and therefore shows the ability to adopt quantitative imaging in broad neuroscientific and clinical applications.