Sci‐Fri AM: MRI and Diagnostic Imaging ‐ 01: Estimating the Transverse Relaxation Time of Taurine Protons in Rat Brain at 9.4 T with Optimized PRESS Sequence Timings

Purpose: To investigate the response of taurine (Tau) protons as a function of PRESS echo times, TE 1 and TE 2 , to determine two TE combinations that can be employed to estimate the T 2 (transverse relaxation) value of Tau at 9.4 T. The Tau protons are involved in J‐coupling interactions; therefore, the two timing combinations should result in similar signal losses due to J‐coupling. Methods: Experiments were performed with a 9.4 T animal MRI scanner. Numerical calculations of the response of Tau as a function of PRESS TE 1 and TE 2 were calculated and two TE combinations that yield a similar area for the 3.42 ppm Tau resonance were selected as optimal. The timings were verified on a 50 mM Tau/10 mM Cr (creatine) phantom. In‐vivo experiments were performed on four rats. Spectra were acquired with the timings from a voxel placed in the rat brain and Tau peak areas were fit to monoexponentially decaying functions to obtain T 2 values. Results: The PRESS TE combinations selected for Tau T 2 determination are {TE 1 , TE 2 } = {17 ms, 10 ms} and {80 ms, 70 ms}; the signal yield for the two timings differs by 5 % theoretically. The average Tau T 2 for the four rats was found to be 106 ms with a standard deviation of 12 ms. Conclusions: We have demonstrated that acquiring PRESS spectra with {TE 1 , TE 2 } = {17 ms, 10 ms} and {TE 1 , TE 2 } = {80 ms, 70 ms} enables T 2 corrected measures of Tau to be obtained at 9.4 T.