Figure 8.

Simultaneous multislice imaging utilizes multiple‐channel coil arrays to separate multiple slices excited simultaneously (shown in orange and blue in (a)). The collapsed slices can be separated using parallel imaging, given there are sufficient variations in the coil sensitivities. However, in the case of high slice acceleration, the distances between the aliased voxels become small, making it difficult to resolve the aliasing due to the lack of coil sensitivity variations (b). The result is residual artifacts and amplified noise (g‐factor penalty) in the reconstructed images. With CAIPI scheme (eg, blipped‐CAIPI in SSH‐EPI), the distances between slices are increased by an apparent shifting along the phase‐encoding direction (c), which can significantly improve the reconstruction.