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Simultaneous PET-MRI reveals brain function in activated and resting state on metabolic, hemodynamic and multiple temporal scales

Abstract

Combined positron emission tomography (PET) and magnetic resonance imaging (MRI) is a new tool to study functional processes in the brain. Here we study brain function in response to a barrel-field stimulus simultaneously using PET, which traces changes in glucose metabolism on a slow time scale, and functional MRI (fMRI), which assesses fast vascular and oxygenation changes during activation. We found spatial and quantitative discrepancies between the PET and the fMRI activation data. The functional connectivity of the rat brain was assessed by both modalities: the fMRI approach determined a total of nine known neural networks, whereas the PET method identified seven glucose metabolism–related networks. These results demonstrate the feasibility of combined PET-MRI for the simultaneous study of the brain at activation and rest, revealing comprehensive and complementary information to further decode brain function and brain networks.

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Figure 1: Comparison of PET and fMRI activation.
Figure 2: Quantification of PET-MRI stimulus response.
Figure 3: PET-MRI functional connectivity.
Figure 4: Networks in the whisker system.

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Acknowledgements

We thank F. Cay and M. Koenig for excellent technical support during this project. This study was supported by the German Research Foundation (Deutsche Forschungsgemeinschaft PI 771/1-1, PI 771/5-1), the Wilhelm Schuler-Foundation and the Werner Siemens-Foundation.

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Authors and Affiliations

Authors

Contributions

H.F.W. and B.J.P. designed the study, evaluated and analyzed data and prepared the manuscript, H.F.W., M.H., K.L., C.-C.L., I.B. and B.J.P. developed the PET insert, G.R. produced the radiotracer, H.F.W. and M.H. made PET-MRI measurements, H.F.W., P.M. and F.S. developed the MRI sequence, and all authors read and edited the manuscript.

Corresponding author

Correspondence to Bernd J Pichler.

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Competing interests

B.J.P. receives grant and research support from AstraZeneca, Bayer Healthcare, Boehringer-Ingelheim, Bruker, Oncodesign, Merck, Siemens and the Werner Siemens-Foundation. K.L. is an employee of Bruker.

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Supplementary Figures 1–11, Supplementary Tables 1 and 2, Supplementary Results, Supplementary Discussion and Supplementary Methods (PDF 5899 kb)

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Wehrl, H., Hossain, M., Lankes, K. et al. Simultaneous PET-MRI reveals brain function in activated and resting state on metabolic, hemodynamic and multiple temporal scales. Nat Med 19, 1184–1189 (2013). https://doi.org/10.1038/nm.3290

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