Simultaneous multislice (SMS) imaging provides through-plane acceleration. While current reconstruction methods for non-Cartesian imaging (and also for Cartesian imaging) utilize either in-plane or through-plane coil information, we reasoned that a slice-SPIRiT model could utilize both in-plane and through-plane kernel calibration information, and potentially outperform methods like conjugate-gradient SENSE (CG-SENSE). We developed a slice-SPIRiT method and compared it to CG-SENSE for spiral cardiac cine imaging. Slice leakage artifacts using slice-SPIRiT were 52.9% lower than using CG-SENSE in phantoms, and the artifact power of slice-SPIRiT was 24.2% less than CG-SENSE in five volunteers. Slice-SPIRiT is a promising method for spiral SMS imaging.