Comparison of block and event‐related experimental designs in diffusion‐weighted functional MRI. Issue 2 (29th October 2013)

• Record Type: Journal Article
• Authors: Williams, Rebecca J.; McMahon, Katie L.; Hocking, Julia; Reutens, David C.
• Is Part Of: Journal of magnetic resonance imaging. Volume 40:Issue 2(2014)
• Page Start: 367
• Page End: 375
• Publication Date: 2013-10-29
• Subjects: Magnetic resonance imaging -- Periodicals; 616
• DOI: 10.1002/jmri.24353
• Languages: English
• ISSNs: 1053-1807

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="jmri24353-sec-0001" sec-type="section"> <title>Purpose</title> <p>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.</p> </sec> <sec id="jmri24353-sec-0002" sec-type="section"> <title>Materials and Methods</title> <p>Nine participants viewed contrast reversing (7.5 Hz) black‐and‐white checkerboard stimuli using block and event‐related paradigms. DfMRI (b = 1800 mm/s<sup>2</sup>) 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.</p> </sec> <sec id="jmri24353-sec-0003" sec-type="section"> <title>Results</title> <p>The BOLD conditions showed a higher percent signal change relative to DfMRI; however, event‐related DfMRI showed the strongest group activation (<italic>t</italic> = 21.23, <italic>P</italic> < 0.0005). Activation was more diffuse and spatially closer to the BOLD response for DfMRI when the block design was used. DfMRI<sub>event</sub> showed the shortest TTP (4.4 ± 0.88 sec).</p> </sec> <sec id="jmri24353-sec-0004" sec-type="section"> <title>Conclusion</title> <p>The hemodynamic contribution to DfMRI may increase with the use of block designs. <bold>J. Magn. Reson. Imaging 2014;40:367–375</bold>. © <bold>2013 Wiley Periodicals, Inc</bold>.</p> </sec> </abstract>