title: Comparison of k-t SENSE/k-t BLAST with conventional SENSE applied to BOLD fMRI.
abstract: OBJECTIVE
  To compare k-t BLAST (broad-use linear-acquisition speedup technique)/k-t SENSE (sensitivity encoding) with conventional SENSE applied to a simple fMRI paradigm.
  
  
  METHODS
  Blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) was performed at 3 T using a displaced ultra-fast low-angle refocused echo (UFLARE) pulse sequence with a visual stimulus in a block paradigm. Conventional SENSE and k-t BLAST/k-t SENSE data were acquired. Also, k-t BLAST/k-t SENSE was simulated at different undersampling factors from fully sampled data after removal of lines of k-space data. Analysis was performed using SPM5.
  
  
  RESULTS
  Sensitivity to the BOLD response in k-t BLAST/k-t SENSE was comparable with that of SENSE in images acquired at an undersampling factor of 2.3. Simulated k-t BLAST/k-t SENSE yielded reliable detection of activation-induced BOLD contrast at undersampling factors of 5 or less. Sensitivity increased significantly when training data were included in k-space before Fourier transformation (known as "plug-in").
  
  
  CONCLUSIONS
  k-t BLAST/k-t SENSE performs at least as well as conventional SENSE for BOLD fMRI at a modest undersampling factor. Results suggest that sufficient sensitivity to BOLD contrast may be achievable at higher undersampling factors with k-t BLAST/k-t SENSE than with conventional parallel imaging approaches, offering particular advantages at the highest magnetic field strengths.
authors.affiliation: Division of Experimental Magnetic Resonance Imaging, Department of Diagnostic Radiology, Faculty of Medicine, RWTH-Aachen, Aachen, Germany. j.utting@nhs.net
authors.forename: Jane F
authors.initials: JF
authors.lastname: Utting
authors.forename: Sebastian
authors.initials: S
authors.lastname: Kozerke
authors.forename: Ralph
authors.initials: R
authors.lastname: Schnitker
authors.forename: Thoralf
authors.initials: T
authors.lastname: Niendorf
mesh_terms: D017352:Echo-Planar Imaging / Q000379:methods; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D012016:Reference Values; D012680:Sensitivity and Specificity