Figure 8.

Signal intensity and tSNR comparison for the acquisitions with a constant flip‐angle and the data acquired with a flip‐angle sweep. A, The 4 LL readouts of the fourth Hadamard labeling block. The ASL signal decreased over the multiple LL readouts when a constant flip‐angle of 35° was used, which would lead to modulations in the SNR of the ASL signal over the 28 time points. A constant signal over the 4 LL readouts was obtained by using a flip‐angle sweep of 30°, 35°, 45°, and 90°. B, Mean GM and arterial tSNR of all volunteers for both acquisitions over time, that is, either with constant flip‐angle or by using a flip‐angle sweep, demonstrating a higher tSNR for the third and fourth LL phase when a flip‐angle sweep is utilized as compared to the tSNR for the acquisitions with a constant flip‐angle. The constant flip‐angle readout train resulted in higher tSNR for the first phase for the longer PLDs. Significant difference (P < 0.05) is indicated with an asterisk. a.u. = arbitrary units