title: Investigation of long-term reproducibility of intrinsic connectivity network mapping: a resting-state fMRI study.
abstract: OBJECTIVE
  Connectivity mapping based on resting-state fMRI is rapidly developing, and this methodology has great potential for clinical applications. However, before resting-state fMRI can be applied for diagnosis, prognosis, and monitoring treatment for an individual patient with neurologic or psychiatric diseases, it is essential to assess its long-term reproducibility and between-subject variations among healthy individuals. The purpose of the study was to quantify the long-term test-retest reproducibility of ICN measures derived from resting-state fMRI and to assess the between-subject variation of ICN measures across the whole brain.
  
  
  METHODS
  Longitudinal resting-state fMRI data of 6 healthy volunteers were acquired from 9 scan sessions during >1 year. The within-subject reproducibility and between-subject variation of ICN measures, across the whole brain and major nodes of the DMN, were quantified with the ICC and COV.
  
  
  RESULTS
  Our data show that the long-term test-retest reproducibility of ICN measures is outstanding, with >70% of the connectivity networks showing an ICC > 0.60. The COV across 6 healthy volunteers in this sample was >0.2, suggesting significant between-subject variation.
  
  
  CONCLUSIONS
  Our data indicate that resting-state ICN measures (eg, the correlation coefficients between fMRI signal-intensity profiles from 2 different brain regions) are potentially suitable as biomarkers for monitoring disease progression and treatment effects in clinical trials and individual patients. Because between-subject variation is significant, it may be difficult to use quantitative ICN measures in their current state as a diagnostic tool.
authors.affiliation: Center for the Study of Aging and Human Development, Duke University, Durham, NC 27710, USA.
authors.forename: Y-h
authors.initials: YH
authors.lastname: Chou
authors.forename: L P
authors.initials: LP
authors.lastname: Panych
authors.forename: C C
authors.initials: CC
authors.lastname: Dickey
authors.forename: J R
authors.initials: JR
authors.lastname: Petrella
authors.forename: N-k
authors.initials: NK
authors.lastname: Chen
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000502:physiology*; D009434:Neural Pathways / Q000502:physiology*; D015203:Reproducibility of Results; D012146:Rest / Q000502:physiology; D012680:Sensitivity and Specificity; D055815:Young Adult