Dependency on Tissue Anisotropy and White Matter Fiber Orientation of Phase-Cycled bSSFP Relaxometry at 3 Tesla
Key Points
All metrics (T1, T2, AI) demonstrated sensitivity to white matter fiber orientation and fractional anisotropy, highlighting their importance in neuroimaging.
Phase-cycled bSSFP effectively quantifies relaxation parameters that relate to brain tissue microstructure, offering insights into tissue integrity.
Diffusion tensor imaging was utilized alongside pc-bSSFP to correlate metrics with tissue structure, underscoring robust methodology across a large cohort.
Results indicate that relaxation parameters are dependent on unique tissue characteristics, calling for further explorations into clinical applications.
Abstract
Motivation: Magnetic resonance relaxation anisotropy in tissue has been reported previously for both T1 and T2, with implications to assess the integrity of tissue microstructure. Goal(s): To evaluate the dependency on brain tissue anisotropy and white matter fiber orientation of relaxometry metrics (T1, T2) and asymmetry index (AI), derived from phase-cycled bSSFP (pc-bSSFP), in a large cohort of healthy subjects. Approach: 80 healthy subjects were scanned at 3T using pc-bSSFP and diffusion tensor imaging. T1 and T2 were quantified using MIRACLE - an SSFP configuration-based approach. Results: All metrics (T1, T2, AI) showed a distinct sensitivity to white matter fiber orientation and fractional anisotropy. Impact: Relaxation parameters and frequency profile asymmetries derived from pc-bSSFP demonstrated a distinct sensitivity to brain tissue microstructure, with a dependency on white matter fiber orientation and fractional anisotropy.