Comparison of block and event‐related experimental designs in diffusion‐weighted functional MRI

Authors:
Publisher website
Google Scholar
Abstract
Purpose: To compare diffusion‐weighted functional magnetic resonance imaging (DfMRI), a novel alternative to the blood oxygenation level‐dependent (BOLD) contrast, in a functional MRI experiment.Materials and Methods: Nine participants viewed contrast reversing (7.5 Hz) black‐and‐white checkerboard stimuli using block and event‐related paradigms. DfMRI (b = 1800 mm/s2) and BOLD sequences were acquired. Four parameters describing the observed signal were assessed: percent signal change, spatial extent of the activation, the Euclidean distance between peak voxel locations, and the time‐to‐peak of the best fitting impulse response for different paradigms and sequences.Results: The BOLD conditions showed a higher percent signal change relative to DfMRI; however, event‐related DfMRI showed the strongest group activation (t = 21.23, P < 0.0005). Activation was more diffuse and spatially closer to the BOLD response for DfMRI when the block design was used. DfMRIevent showed the shortest TTP (4.4 ± 0.88 sec).Conclusion: The hemodynamic contribution to DfMRI may increase with the use of block designs. J. Magn. Reson. Imaging 2014;40:367–375. © 2013 Wiley Periodicals, Inc.

This publication has 31 references indexed in Scilit: