Demonstration of the phase modulation strategy for 8 spiral interleaves at MB = 1,2,3 and 4. (a) Spiral perfusion images acquired separately from 4 slice positions. (b) Hadamard excitation RF phase modulation pattern as applied to each slice position for MB factors of 1–4. (c) For slices 2–4 there is nearly complete suppression of image with an incoherent residual aliasing artifact that varies by slice position. (d) The combined SMS images for MB factors 1–4 show the image at slice position 1 with superposition of the aliasing patterns from the other slices as shown in (c). By applying phase demodulation, the images from the other slice locations can be generated through phase demodulation as shown in (e, f and g). Images at each slice location have a different aliasing pattern in time due to golden angle rotation of the trajectory, and the residual aliasing can be removed using an SMS-L1-SPIRiT reconstruction.