Concordance of 18F-FDG PET Uptake in Tumor and Normal Tissues on PET/MRI and PET/CT

Aim: The aim of this study was to assess the concordance of PET measurements of F-18-FDG uptake in tumor and normal tissues obtained on Australia's first clinical PET/MRI scanner in comparison to PET/CT, with comparison against published data. Methods: One hundred subjects were prospectively recruited from an unselected, heterogeneous group of cancer patients to undergo F-18-FDG PET/CT and PET/MRI on the same day. SUVs of physiological regions and tumor tissues obtained by PET/MRI and PET/CTwere compared and benchmarked against existing published data. Physiological activity was measured in the thoracic aorta and right lobe of the liver. Tumor SUVs were analyzed by cancer type, body region, and a combined group of all lesions. Results: There was an excellent correlation between SUV measurements in tumor lesions obtained by PET/MRI and PET/CT, across all body regions and in all tumor types studied. There was a less robust correlation for SUVs measured in areas of physiological activity, but the level of agreement still fell within 2 SDs of mean. Data from this study showed comparable or smaller systemic biases and narrower confidence limits than existing studies in the literature comparing SUVs from PET/MRI and PET/CT. Conclusions: F-18-FDG PET/MRI appears promising as an adjunct or alternative to PET/CT for quantitative evaluation in oncology, independent of body region and tumor type, across a wide range of SUVs.