FIGURE 9.

The quantitative ${\mathrm{T}}_2^{\ast }$ and tissue phase maps at 72× and 32× retrospective undersampling with VDS temporal‐variant CAIPI. The scan time of fully sampled scan was 25 minutes at 1.1 mm isotropic resolution, which can be reduced to 21 seconds and 48 seconds by 72× and 32× folds acceleration, respectively. At R = 72, the tissue phase is comparable to reference, but ${\mathrm{T}}_2^{\ast }$ map shows artifacts and noise. Using R = 32, the error of ${\mathrm{T}}_2^{\ast }$ map is reduced with higher SNR, and the acquisition time is still less than 1 minute