Comparison of k‐t SENSE/k‐t BLAST with conventional SENSE applied to BOLD fMRI

Purpose: 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. Materials and 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”). Conclusion: 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. J. Magn. Reson. Imaging 2010;32:235–241. © 2010 Wiley‐Liss, Inc.