4-D PET joint image reconstruction/non-rigid motion estimation with limited MRI prior information

Abstract

Motion compensated gated PET image reconstruction methods include joint-reconstruction (JR) and indirect reconstruction (IR) with pre-estimated motion from MRI (MRI-IR). JR suffers from poor PET data quality whereas MRI-IR requires high-quality MRI volumes at each gate. We propose a penalised maximum-likelihood approach combining JR and MRI-IR. Our method is referred to as minimal MRI prior JR (MP-JR).The M gates data are stored in g = [g1; …; gM] where gm is the measurement vector at gate m. Each gm is a Poisson distributed vector of parameter where P is the projector, W(αm) is the m-th motion of parameter αm, rm is the m-th average random/scatter vector and f is the activity at m = 1. JR is achieved with (1).1MRI-IR is achieved by solving (2)2MP-JR is achieved with (3).3The first term accounts for PET data, whereas the second term accounts for MRI motion information from subset S. The last term controls temporal smoothness.We tested each method on 9 PET FDG volumes generated from a ...