title: Reliability of Task-Based fMRI for Preoperative Planning: A Test-Retest Study in Brain Tumor Patients and Healthy Controls.
abstract: BACKGROUND
  Functional magnetic resonance imaging (fMRI) continues to develop as a clinical tool for patients with brain cancer, offering data that may directly influence surgical decisions. Unfortunately, routine integration of preoperative fMRI has been limited by concerns about reliability. Many pertinent studies have been undertaken involving healthy controls, but work involving brain tumor patients has been limited. To develop fMRI fully as a clinical tool, it will be critical to examine these reliability issues among patients with brain tumors. The present work is the first to extensively characterize differences in activation map quality between brain tumor patients and healthy controls, including the effects of tumor grade and the chosen behavioral testing paradigm on reliability outcomes.
  
  
  METHODS
  Test-retest data were collected for a group of low-grade (n = 6) and high-grade glioma (n = 6) patients, and for matched healthy controls (n = 12), who performed motor and language tasks during a single fMRI session. Reliability was characterized by the spatial overlap and displacement of brain activity clusters, BOLD signal stability, and the laterality index. Significance testing was performed to assess differences in reliability between the patients and controls, and low-grade and high-grade patients; as well as between different fMRI testing paradigms.
  
  
  RESULTS
  There were few significant differences in fMRI reliability measures between patients and controls. Reliability was significantly lower when comparing high-grade tumor patients to controls, or to low-grade tumor patients. The motor task produced more reliable activation patterns than the language tasks, as did the rhyming task in comparison to the phonemic fluency task.
  
  
  CONCLUSIONS
  In low-grade glioma patients, fMRI data are as reliable as healthy control subjects. For high-grade glioma patients, further investigation is required to determine the underlying causes of reduced reliability. To maximize reliability outcomes, testing paradigms should be carefully selected to generate robust activation patterns.
authors.affiliation: Physical Sciences Platform, Sunnybrook Research Institute, Toronto, ON, Canada.|Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.
authors.forename: Melanie A
authors.initials: MA
authors.lastname: Morrison
authors.affiliation: Keenan Research Centre, St. Michael's Hospital, Toronto, ON, Canada.
authors.forename: Nathan W
authors.initials: NW
authors.lastname: Churchill
authors.affiliation: Keenan Research Centre, St. Michael's Hospital, Toronto, ON, Canada.|Division of Neurosurgery, St. Michael's Hospital, Toronto, ON, Canada.|Department of Surgery, University of Toronto, Toronto, ON, Canada.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Cusimano
authors.affiliation: Keenan Research Centre, St. Michael's Hospital, Toronto, ON, Canada.|Division of Neurosurgery, St. Michael's Hospital, Toronto, ON, Canada.|Department of Surgery, University of Toronto, Toronto, ON, Canada.
authors.forename: Tom A
authors.initials: TA
authors.lastname: Schweizer
authors.affiliation: Keenan Research Centre, St. Michael's Hospital, Toronto, ON, Canada.|Division of Neurosurgery, St. Michael's Hospital, Toronto, ON, Canada.|Department of Surgery, University of Toronto, Toronto, ON, Canada.
authors.forename: Sunit
authors.initials: S
authors.lastname: Das
authors.affiliation: Physical Sciences Platform, Sunnybrook Research Institute, Toronto, ON, Canada.|Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Graham
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000175:diagnosis*; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D005910:Glioma / Q000175:diagnosis*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care; D015203:Reproducibility of Results; D013647:Task Performance and Analysis; D055815:Young Adult