title: Functional MR imaging on an open 1T MR imaging system: exploiting the advantages of an open MR imaging system for functional MR imaging.
abstract: OBJECTIVE
  Open MR imaging scanners are designed for imaging of specific patient groups that cannot be routinely scanned with conventional MR imaging scanners (eg, patients with obesity and claustrophobia). This study aims to determine whether BOLD sensitivity on an open 1T scanner is adequate for fMRI for diagnostic and research purposes by directly comparing fMRI results with a standard 3T MR imaging scanner. The optimal TE was also determined.
  
  
  METHODS
  Twelve healthy adults were scanned by using both an open 1T scanner and a standard 3T scanner. Gradient-echo echo-planar images were acquired for all subjects while performing motor and affective paradigms, each at 5 different TEs per scanner (range, 40-80 ms at open 1T; 20-40 ms at 3T). To compare BOLD sensitivity between scanners and TEs, we determined maximum statistical t scores per TE for all relevant brain areas (motor cortex, visual cortex, amygdala, and OFC) for individual subjects and group analyses. Additionally, T2* values were determined per scanner for the relevant brain areas.
  
  
  RESULTS
  Maximum t scores were significantly lower in the relevant brain areas on the open 1T compared with the 3T for single subjects but not for group analyses. The optimal TE for fMRI on an open 1T MR imaging system was found to be approximately 70 ms.
  
  
  CONCLUSIONS
  Although for single-subject studies as used in diagnostics, 3T was found to be superior, fMRI on an open 1T MR imaging scanner is suitable for research designed to analyze data at a group level.
authors.affiliation: Department of Nuclear Medicine, Academic Medical Center, University of Amsterdam, the Netherlands. e.m.vandegiessen@amc.uva.nl
authors.forename: E
authors.initials: E
authors.lastname: van de Giessen
authors.forename: P F C
authors.initials: PF
authors.lastname: Groot
authors.forename: J
authors.initials: J
authors.lastname: Booij
authors.forename: W
authors.initials: W
authors.lastname: van den Brink
authors.forename: D J
authors.initials: DJ
authors.lastname: Veltman
authors.forename: A J
authors.initials: AJ
authors.lastname: Nederveen
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014796:Visual Perception / Q000502:physiology*