Figure 4.

Bloch simulations for the MPFLAGRE‐4 sequence, adding a delayed S₄ block. See Figure 3A for the time course. Behavior of 5 tissue components identified CSF (blue), GM (black), and WM (red); and GM and WM with long T₂ values for pathology. Calculated R intensities are shown: R_1/3 and R_(1+2)/3 intensities as a function of T₁, T₂ space (A) and plots of signal amplitude from the 5 tissue points (far right). B, The R_1/4 and R_(1+2)/4 intensities. The R_1/3, R_(1+2)/3 amplitudes show CSF suppression and increased amplitudes over long T₂ components. The R_1/4 amplitude shows predominantly T₂ dependence. The R_(1+2)/4 intensity, similar to R_(1+2)/3, shows a larger dynamic range for T₂ dependence