[18F]FDG brain PET-MR versus PET/CT in a clinical cohort: intra-subject quantitative comparisons

There is limited evidence on the advantages of brain 2-deoxy-2-[18F]fluoroglucose (FDG) positron emission tomography (PET) with simultaneous magnetic resonance imaging (PET-MR) over PET with computed tomography (PET/CT). We quantitatively compared brain FDG PET/CT and PET-MR images from a large clinical cohort. Participants with refractory epilepsy or cognitive problems underwent PET/CT at approximately 30 min post-injection, followed by PET-MR at approximately 100 min.

Standardized uptake values (SUVs) were extracted in anatomical regions using a multi-atlas method, and voxel-wise comparisons were performed with statistical parametric mapping. Fifty-five image pairs passed quality control. Within-subject correlations between modalities were very high (0.96, range 0.84–0.99); within-region, across-participant correlations were 0.82 (0.72–0.90).

PET-MR SUVs were on average 20% higher than PET/CT, more so for higher-uptake regions. Voxel-wise, PET-MR showed relatively higher uptake in visual and auditory cortices, lower uptake in medial frontal and anteromesial temporal cortices, and better grey-white matter contrast. We found a very close correspondence between the two modalities with their respective attenuation correction methods and sensory activation between scans; the different uptake times explain differences in absolute SUV levels and grey-white matter contrast.

With awareness of these differences, brain PET-MR can be used clinically. (FMRIB [Functional Magnetic Resonance Imaging of the Brain] Software Library) Multi-atlas propagation with enhanced registration Magnetization-prepared rapid gradient echo Ordinary Poisson Ordered Subset Expectation Maximisation Positron emission tomography/computed tomography Positron emission tomography-magnetic resonance We would like to thank all the technologists and technical staff at the King’s College London & Guy’s and St Thomas’ PET Centre for supporting this work, and the participants for donating their time. This study did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. The School of Biomedical Engineering and Imaging Sciences is supported by the Wellcome EPSRC Centre for Medical Engineering at King’s College London (WT 203148/Z/16/Z) and the Department of Health via the National Institute for Health Research (NIHR) comprehensive Biomedical Research Centre award to Guy’s & St Thomas’ NHS Foundation Trust in partnership with King’s College London and King’s College Hospital NHS Foundation Trust.

King’s College London & Guy’s and St Thomas’ PET Centre, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, UK Arick Sagel Martinez, Anthime Flaus, Joel Dunn, Sufian Al-Ethawi, Sami Jeljeli, Colm J. McGinnity & Alexander Hammers Nuclear Medicine Department, Hospices Civils de Lyon, Medical Faculty of Lyon Est, University Claude Bernard Lyon 1, Lyon, France Lyon Neuroscience Research Center, INSERM U1028/CNRS UMR5292, Lyon, France Department of Medical Radiation Sciences, University of Gothenburg, Gothenburg, Sweden Research Department of Biomedical Computing, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, UK Research Department of Early Life Imaging, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, UK The authors declare no competing interests. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

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