Line-Scan Gradient Echo Sampling of Turbo Spin Echo (GESTSE) Enables Quantitative Relaxometry in a “Virtual Biopsy” with 150 µm Resolution

Motivation: Need for quantitative relaxometry at the spatial scale of cortical laminae to detect layer-specific pathology. Goal(s): Demonstrate feasibility of Line-Scanned Gradient Echo Sampling of Turbo Spin Echo (GESTSE)Approach: Novel 1D GESTSE sequence was developed, and data acquired in water phantom and pineapple at 7T. Data fitting algorithm was developed to accurately fit observed measurements and extract quantitative relaxometry data. Results: With specific gradient spoiling and phase cycling, and a fitting algorithm that accounts for system imperfections, transverse relaxation constants can be estimated at a 150 µm resolution along a 1D line-scan. Impact: Our novel line-scan GESTSE sequence and fitting algorithm enables accurate quantitative relaxometry at spatial scales sufficient to resolve human cortical laminae. This method offers a new avenue to efficiently detect layer-specific cortical structure and pathology in vivo.