Investigation of BOLD contrast in fMRI using multi‐shot EPI

High resolution volume coverage of the brain in fMRI studies can be accomplished using multi‐slice, multi‐shot EPI. We demonstrate that the optimum contrast sensitivity in BOLD based fMRI experiments using multi‐shot EPI is achieved by using the shortest possible TR values beween segments and the longest tolerable echo train length. For a fixed paradigm time, acquiring the largest number of images under these conditions yields the best statistical detection thresholds. For a multi‐slice multi‐shot EPI fMRI study, the best approach is to perform the acquisition of all the segments in a single slice before continuing on to each of the slices in turn. Our results regarding the number of shots and TR are also applicable to other multi‐shot techniques such as interleaved spirals. © 1997 John Wiley & Sons, Ltd.

[1]  S. Ogawa.  Brain magnetic resonance imaging with contrast-dependent oxygenation , 1990 .

[2]  X. Hu,et al.  Reduction of signal fluctuation in functional MRI using navigator echoes , 1994, Magnetic resonance in medicine.

[3]  K. Uğurbil,et al.  Experimental determination of the BOLD field strength dependence in vessels and tissue , 1997, Magnetic resonance in medicine.

[4]  E C Wong,et al.  Processing strategies for time‐course data sets in functional mri of the human brain , 1993, Magnetic resonance in medicine.

[5]  Ravi S. Menon,et al.  Intrinsic signal changes accompanying sensory stimulation: functional brain mapping with magnetic resonance imaging. , 1992, Proceedings of the National Academy of Sciences of the United States of America.

[6]  R. S. Hinks,et al.  Time course EPI of human brain function during task activation , 1992, Magnetic resonance in medicine.

[7]  R. Turner,et al.  Dynamic magnetic resonance imaging of human brain activity during primary sensory stimulation. , 1992, Proceedings of the National Academy of Sciences of the United States of America.

[8]  S. Ogawa,et al.  BOLD Based Functional MRI at 4 Tesla Includes a Capillary Bed Contribution: Echo‐Planar Imaging Correlates with Previous Optical Imaging Using Intrinsic Signals , 1995, Magnetic resonance in medicine.

[9]  J. Strupp.  Stimulate: A GUI based fMRI analysis software package , 1996, NeuroImage.

[10]  Xiaoping Hu,et al.  Potential pitfalls of functional MRI using conventional gradient‐recalled echo techniques , 1994, NMR in biomedicine.

[11]  D. Tank,et al.  Brain magnetic resonance imaging with contrast dependent on blood oxygenation. , 1990, Proceedings of the National Academy of Sciences of the United States of America.

[12]  D. Tank,et al.  4 Tesla gradient recalled echo characteristics of photic stimulation‐induced signal changes in the human primary visual cortex , 1993 .

[13]  E. Haacke,et al.  Identification of vascular structures as a major source of signal contrast in high resolution 2D and 3D functional activation imaging of the motor cortex at l.5T preliminary results , 1993, Magnetic resonance in medicine.