Three-Dimensional Balanced Steady State Free Precession Ultra-short Echo Time MRI for Multiple Contrasts Whole Brain Imaging

Motivation: Typical ultra-short echo time (UTE) sequences lack of meaningful contrast for long T2 components, and lack of straightforward method to derive images with only ultra-short T2 (uT2) components. Goal(s): To develop a novel high-resolution fast UTE MRI sequence, potentially for myelin imaging. Approach: The sequence was developed based on combining balanced steady-state free precession (bSSFP) and UTE techniques, together with a 3D rosette dual-echo k-space trajectory. Results: The sequence provides PD contrast in both echo times (TEs) and enables easy separation of uT2 components by subtraction between two TEs, which is sensitive to MS patients’ lesions. Impact: The fast and high-resolution (0.94 mm isotropic resolution under three minutes) dual-echo bSSFP UTE sequence provides both structural information (PD contrast) and uT2 components imaging for myelin quantification (by subtraction). It has great potential aiding diagnosis of multiple sclerosis patients.