T1ρ dispersion imaging is a very time-consuming process because full T1ρ-mapping at different spin-lock amplitudes is required. Due to this issue, investigation of T1ρ dispersion is hardly feasible in the limited measurement time of a small animal experiment. In this work, we present a novel approach for the rapid measurement of cardiac T1ρ dispersion called dispersion reconstruction. With our new concept a T1ρ dispersion image is generated by only acquiring a fraction of the required mapping data. Phantom and in vivo experiments confirm the applicability of our new method as part of a conventional protocol for small animal studies.