A 4-minute solution for submillimeter whole-brain T_1ρ quantification

Purpose: To develop a robust, accurate, and accelerated T_1ρ quantification solution for submillimeter in vivo whole-brain imaging. Methods: A multislice T_1ρ mapping solution (MS-T_1ρ) was developed based on a two-acquisition scheme using turbo spin echo with RF cycling to allow for whole-brain coverage with 0.8-mm in-plane resolution. A compressed sensing–based fast imaging method, SCOPE, was used to accelerate the MS-T_1ρ acquisition time to a total scan time of 3 minutes 31 seconds. A phantom experiment was conducted to assess the accuracy of MS-T_1ρ by comparing the T_1ρ value obtained using MS-T_1ρ with the reference value obtained using the standard single-slice T_1ρ mapping method. In vivo scans of 13 volunteers were acquired prospectively to validate the robustness of MS-T_1ρ. Results: In the phantom study, the T_1ρ values obtained with MS-T_1ρ were in good agreement with the reference T_1ρ values (R² = 0.9991) and showed high consistency throughout all slices (coefficient of variation = 2.2 ± 2.43%). In the in vivo experiments, T_1ρ maps were successfully acquired for all volunteers with no visually noticeable artifacts. There was no significant difference in T_1ρ values between MS-T_1ρ acquisitions and fully sampled acquisitions for all brain tissues (p-value >.05). In the intraclass correlation coefficient and Bland-Altman analyses, the accelerated T_1ρ measurements show moderate to good agreement to the fully sampled reference values. Conclusion: The proposed MS-T_1ρ solution allows for high-resolution whole-brain T_1ρ mapping within 4 minutes and may provide a potential tool for investigating neural diseases.