Development of a Double Echo-Shifted QUTE for quantification of T2* relaxation time at Ultra-High Field MRI.

Motivation: T2* relaxation time is typically assessed using a multi-echo GRE sequence. However, the accurate quantification of slow-relaxing water pools, such as CSF, necessitates an extended scan time in comparison to that required for the quantification of brain tissue. Goal(s): We present a new sequence (DES-QUTE), which is capable of acquiring three bunches of echoes corresponding to short, intermediate, and long TEs without a significant increase in the scan time. Approach: The proposed sequence integrates QUTE with an improved echo-shifting technique. Results: The DES-QUTE demonstrated accurate and precise T2* quantification at ultra-high field MRI, while providing a potential for simultaneous quantification of diffusion coefficients. Impact: The proposed sequence offers an opportunity to sample different ranges of TE images and quantify both T2* and D information without a significant increase in scan time. This method is expected to make significant contributions to the study of neurofluids.