Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.05.01.071662v1?rss=1 Authors: Jamadar, S. D., Ward, P. G. D., Liang, E. X., Orchard, W. R., Chen, Z., Egan, G. Abstract: Simultaneous FDG-PET/fMRI ([18F] fluorodeoxyglucose positron emission tomography functional magnetic resonance imaging) provides the capacity to image two sources of energetic dynamics in the brain, glucose metabolism and haemodynamic response. Functional fMRI connectivity has been enormously useful for characterising interactions between distributed brain networks in humans. Metabolic connectivity based on static FDG-PET has been proposed as a biomarker for neurological disease; but static FDG-PET cannot be used to estimate subject-level measures of connectivity, only across-subject covariance. Here, we applied high-temporal resolution constant infusion functional PET (fPET) to measure subject-level metabolic connectivity simultaneously with fMRI connectivity. fPET metabolic connectivity was characterised by fronto-parietal connectivity within and between hemispheres. fPET metabolic connectivity showed moderate similarity with fMRI primarily in superior cortex and frontoparietal regions. fPET metabolic connectivity showed little similarity with static FDG-PET metabolic covariance, indicating that metabolic connectivity is a non-ergodic process that cannot be used to infer individual-level connectivity from across-subject covariance. In sum, our results highlight the complementary strengths of fPET and fMRI in measuring the intrinsic connectivity of the brain, and opens up the opportunity for new multivariate metabolic neuroimaging biomarkers for neurological disease Copy rights belong to original authors. Visit the link for more info