An algorithm for direct 4-D PET image reconstruction/non-rigid motion estimation with limited MRI prior information

MP-JRM performs better in situations where JRM and MRI-IR under-perform. This is because MP-JR relies on both MRI and PET data, whereas JRM and MRI-IR rely on one modality only. In addition, results tend to show that with temporal smoothing on B-spline parameters, a subset of MRI volumes gives enough information to compensate for motion. Further work is in progress to analyse variance and bias as well as reconstruction from real gated data.