Fig. 1
From: Impact of attenuation correction on clinical [18F]FDG brain PET in combined PET/MRI
FDG brain PET image reconstruction and postprocessing. a PET/CT delivered a low-dose CT (intrasystemly CT-derived μ-map not shown), and the resulting PETPETCT served as standard of truth for the visual analysis in this study. b PET/MRI was acquired on the same day. Using different μ-maps but the same reconstruction parameters, four PET datasets were reconstructed in PET/MRI. Dixon-standard Dixon μ-map; CT-derived—Hounsfield units from the low-dose CT were bilinearly transferred to μ values which replaced values in the original Dixon μ-map; PseudoCT—a pseudo CT was calculated using a T1-weighted native MRI according to Poynton et al.[11]; BoneDixon-bone voxels μ values from the vendor specific ultrashort echo time (UTE) sequence were replaced in the original Dixon μ-map. c PETCTderived served as standard for the quantitative analyses across different PET/MRI reconstructions in this study. For each patient, the percent deviations between and PETDixon/PseudoCT/BoneDixon and PETCTderived were calculated, resulting in relatively small deviations compared to gold standard PETCTderived if bone was accounted for (top) and larger deviations if bone was ignored (bottom)