FIG. 1.

k-Space acquisition pattern for the first four time points in a four-shot dynamic series with three echoes. Only a single slice is shown for clarity. Data are acquired in an interleaved fashion, and the combination of four subsequent interleaves yields a fully sampled k-space (R = 1) from which coil sensitivity maps or GRAPPA weights can be determined. Maximum temporal resolution (Δt = TR) can be achieved with R equal to the number of interleaves (here, 4). A reduced temporal resolution with increased SNR is possible with this acquisition pattern, as interleaving results in R = 2 by combining pairs of shots, or R = 1 by combining all four shots.