title: Imaging of cerebral activation at 1.5 T: optimizing a technique for conventional hardware.
abstract: OBJECTIVE
  To empirically optimize a two-dimensional magnetic resonance (MR) imaging technique for detecting changes in signal intensity during cerebral activation with a standard clinical imager.
  
  
  METHODS
  Visual activation experiments were performed while imaging parameters were manipulated in a serial fashion, to test their effect on the percentage change in signal intensity (PCSI). The parameters tested were section thickness, echo time (TE), field of view (FOV), flip angle, radio-frequency (RF) spoiling, number of readout points, and number of signals averaged.
  
  
  RESULTS
  The PCSI for visual activation experiments was typically in the 1%-5% range. The best results were achieved with a small section thickness, long TE, and large FOV. Variations in other acquisition parameters had a negligible influence on the PCSI.
  
  
  CONCLUSIONS
  Good results can be obtained at functional MR imaging with standard 1.5-T hardware. Markedly improved results can be obtained by optimizing several key variables, namely, section thickness, TE, and FOV.
authors.affiliation: Department of Diagnostic Radiology, Mayo Clinic, Rochester, MN.
authors.forename: R M
authors.initials: RM
authors.lastname: Thompson
authors.forename: C R
authors.initials: CR
authors.lastname: Jack
authors.forename: K
authors.initials: K
authors.lastname: Butts
authors.forename: D P
authors.initials: DP
authors.lastname: Hanson
authors.forename: S J
authors.initials: SJ
authors.lastname: Riederer
authors.forename: R L
authors.initials: RL
authors.lastname: Ehman
authors.forename: R W
authors.initials: RW
authors.lastname: Hynes
authors.forename: N J
authors.initials: NJ
authors.lastname: Hangiandreou
mesh_terms: D000328:Adult; D001921:Brain / Q000033:anatomy & histology* / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D010775:Photic Stimulation; D012815:Signal Processing, Computer-Assisted; D014793:Visual Cortex / Q000033:anatomy & histology / Q000502:physiology