Na-23-T(1)Quantification With Saturation Recovery Truefisp And Variable Flip Angle Gre At 3t: A Phantom Study

Purpose The aim of the current study was to compare the reproducibility of sodium (Na-23)-T(1)estimation using a centric-reordered saturation recovery (SR) true fast imaging with steady-state precession (TrueFISP) and a variable flip angle (VFA) spoiled gradient echo (GRE). Additionally, we evaluated the effect of spatial averaging on(23)Na-T(1)estimation by the two methods. Methods Measurements were performed in the phantom, consisting of 10 dm(3)volume rectangular polyethylene container filled with distilled water solution of 0.6% NaCl + 0.004% CuSO4, using a dual-tunable(23)Na/H-1 coil at 3 Tesla.Na-23 images were acquired for FOV = 384 x 384 mm(2)and voxel size = 6 x 6 x 6 mm(3)using: (1) TrueFISP: TR/TE = 900/1.5 ms, flip angle = 90 degrees, bandwidth = 450 Hz/px, and (2) GRE: TR/TE = 30/1.5 ms, bandwidth = 350 Hz/px.Na-23-T(1)weightings were obtained with nonselective saturation prepulses delayed from the center of the k-space acquisition by 25/40/60/130/280 ms (SR-TrueFISP) and by applying different nominal flip angles: 10 degrees/30 degrees/50 degrees/70 degrees/90 degrees (VFA-GRE). Both sequences were acquired twice, applying 20 and 30 spatial averages. The resulting images were B-1-corrected with a double-angle GRE method. Results Image acquisition varied from 5:41 to 9:37 for TrueFISP and from 12:48 to 19:12 min for GRE using 20 and 30 spatial averages, respectively. Higher averaging increased the acquisition time by 53% and mean SNR at scan < 10%, without an effect on(23)Na-T(1)estimations with both methods (SR-Truefisp |Delta| = 1.58 ms, VFA-GRE |Delta| = 0.53 ms; for SNRP < .001). Overall, mean +/- SD of(23)Na-T(1)was found as 51 +/- 3 ms with SR-TrueFISP and 53 +/- 2 ms with VFA-GRE. Conclusion Both SR-TrueFISP and VFA-GRE provided similar(23)Na-T(1)estimates based on the phantom measurements with isotropic resolution.