title: Convergence optimization of parametric MLEM reconstruction for estimation of Patlak plot parameters.
abstract: In dynamic positron emission tomography data many researchers have attempted to exploit kinetic models within reconstruction such that parametric images are estimated directly from measurements. This work studies a direct parametric maximum likelihood expectation maximization algorithm applied to [(18)F]DOPA data using reference-tissue input function. We use a modified version for direct reconstruction with a gradually descending scheme of subsets (i.e. 18-6-1) initialized with the FBP parametric image for faster convergence and higher accuracy. The results compared with analytic reconstructions show quantitative robustness (i.e. minimal bias) and clinical reproducibility within six human acquisitions in the region of clinical interest. Bland-Altman plots for all the studies showed sufficient quantitative agreement between the direct reconstructed parametric maps and the indirect FBP (--0.035x+0.48E--5).
authors.affiliation: MRC Clinical Sciences Centre, Imperial College London, Cyclotron Building, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK. georgios.angelis@mmic.man.ac.uk
authors.forename: Georgios I
authors.initials: GI
authors.lastname: Angelis
authors.forename: Kris
authors.initials: K
authors.lastname: Thielemans
authors.forename: Andri C
authors.initials: AC
authors.lastname: Tziortzi
authors.forename: Federico E
authors.initials: FE
authors.lastname: Turkheimer
authors.forename: Charalampos
authors.initials: C
authors.lastname: Tsoumpas
mesh_terms: D000465:Algorithms; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D049268:Positron-Emission Tomography / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity