Positron emission tomography (PET) attenuation correction artefacts in PET/CT and PET/MRI

Objective:To compare the effect of implanted medical materials on 18F-fludeoxyglucose (18F-FDG) positron emission tomography (PET)/MRI using a Dixon-based segmentation method for MRI-based attenuation correction (MRAC), PET/CT and CT-based attenuation-corrected PET (PETCTAC).Methods:12 patients (8 males and 4 females; age 58±11 years) with implanted medical materials prospectively underwent whole-body 18F-FDG PET/CT and PET/MRI. CT, MRI and MRAC maps as well as PETCTAC and PETMRAC images were reviewed for the presence of artefacts. Their morphology and effect on the estimation of the 18F-FDG uptake (no effect, underestimation, overestimation compared with non-corrected images) were compared. In PETMRAC images, a volume of interest was drawn in the area of the artefact and in a reference site (contralateral body part); the mean and maximum standardised uptake values (SUVmean; SUVmax) were measured.Results:Of 27 implanted materials (20 dental fillings, 3 injection ports, 3 hip prostheses and 1 sternal cercl...