title: Transient effects of tumor location on the functional architecture at rest in glioblastoma patients: three longitudinal case studies.
abstract: BACKGROUND
  The cognitive function of brain tumor patients is affected during the treatment. There is evidence that gliomas and surgery alter the functional brain connectivity but studies on the longitudinal effects are lacking.
  
  
  METHODS
  We acquired longitudinal (pre- and post-radiotherapy) resting-state functional magnetic resonance imaging on three selected glioblastoma patients. These cases were selected to study three models: a lesion involving a functional hub within a central system, a lesion involving a peripheral node within a central system and a lesion involving a peripheral node of a non-central system.
  
  
  RESULTS
  We found that, as expected, the tumor lesion affects connections in close vicinity, but when the lesion relates to a functional hub, these changes involve long-range connections leading to diverse connectivity profiles pre- and post-radiotherapy. In particular, a global but temporary improvement in the post-radiotherapy connectivity was obtained when treating a lesion close to a network hub, such as the posterior Cingulate Cortex.
  
  
  CONCLUSIONS
  This suggests that this node re-establishes communication to nodes further away in the network. Eventually, these observed effects seem to be transient and on the long-term the tumor burden leads to an overall decline of connectivity following the course of the pathology. Furthermore, we obtained that the link between hubs, such as the Supplementary Motor Area and posterior Cingulate Cortex represents an important backbone by means of which within and across network communication is handled: the disruption of this connection seems to imply a strong decrease in the overall connectivity.
authors.affiliation: Department of Radiology, Santa Lucia Foundation, Rome, Italy. noora.tuovinen@unich.it.|Department of Neuroscience and Imaging, "G. D'Annunzio" University, Via dei Vestini 31, 66100, Chieti, CH, Italy. noora.tuovinen@unich.it.|Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria. noora.tuovinen@unich.it.
authors.forename: Noora
authors.identifier: http://orcid.org/0000-0002-8835-5281
authors.initials: N
authors.lastname: Tuovinen
authors.affiliation: Department of Radiology, Santa Lucia Foundation, Rome, Italy.|Faculty of Veterinary Medicine, University of Teramo, Teramo, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: de Pasquale
authors.affiliation: Department of Neuroscience and Imaging, "G. D'Annunzio" University, Via dei Vestini 31, 66100, Chieti, CH, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Caulo
authors.affiliation: Department of Radiology, Santa Lucia Foundation, Rome, Italy.
authors.forename: Chiara Falletta
authors.initials: CF
authors.lastname: Caravasso
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, Tor Vergata University General Hospital, Rome, Italy.
authors.forename: Emilia
authors.initials: E
authors.lastname: Giudice
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, Tor Vergata University General Hospital, Rome, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Miceli
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, Tor Vergata University General Hospital, Rome, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Ingrosso
authors.affiliation: Institut Claudius Regaud, Toulouse, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Laprie
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, Tor Vergata University General Hospital, Rome, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Santoni
authors.affiliation: Department of Radiology, Santa Lucia Foundation, Rome, Italy.|Department of Neuroradiology, University of Magna Graecia, Catanzaro, Italy.
authors.forename: Umberto
authors.initials: U
authors.lastname: Sabatini
mesh_terms: D000368:Aged; D001932:Brain Neoplasms / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery; D005260:Female; D005909:Glioblastoma / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008875:Middle Aged
keywords: Brain tumor; Functional connectivity; Radiotherapy; Resting-state fMRI