FIGURE 3.

Normalized subtracted signal of the phantom experiment using FT‐VSI based VSASL with PLD of 1.2 s and 3D GRASE acquisition. In the VSI pulse trains, block (first row) and composite (second row) refocusing pulses were applied, at ${\mathrm{B}}_1^{+}$ scales of 0.7 (left column), 1.0 (middle column), and 1.3 (right column). Incorrect ${\mathrm{B}}_1^{+}$ settings yielded considerable false signal for block refocusing pulses, which were reduced substantially when using composite refocusing pulses, similar to the findings of numerical simulation results in Figure 2