Functional MRI in human subjects with gradient-echo and spin-echo EPI at 9.4 T

Budde, J., Shajan, G. , Zaitsev, M., Scheffler, K. and Pohmann, R. (2014) Functional MRI in human subjects with gradient-echo and spin-echo EPI at 9.4 T. Magnetic Resonance in Medicine, 71(1), pp. 209-218. (doi: 10.1002/mrm.24656) (PMID:23447097)

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Purpose: The increased signal-to-noise ratio and blood oxygen level dependent signal at ultra-high field can only help to boost the resolution in functional MRI studies if the spatial specificity of the activation signal is improved. At a field strength of 9.4 T, both gradient-echo and spin-echo based echo-planar imaging were implemented and applied to investigate the specificity of human functional MRI. A finger tapping paradigm was used to acquire functional MRI data with scan parameters similar to standard neuroscientific applications. Methods: Spatial resolution, echo, and readout times were varied to determine their influence on the distribution of the blood oxygen level dependent signal. High-resolution co-localized images were used to classify the signal according to its origin in veins or tissue. Results: High-quality activation maps were obtained with both sequences. Signal contributions from tissue were found to be smaller or slightly larger than from veins. Gradient-echo echo-planar imaging yielded lower ratios of micro-/macro-vascular signals of around 0.6 than spin-echo based functional MRI, where this ratio varied between 0.75 and 1.02, with higher values for larger echo and shorter readout time. Conclusion: This study demonstrates the feasibility of human functional MRI at 9.4 T with high spatial specificity. Although venous contributions could not be entirely suppressed, venous effects in spin-echo echo-planar imaging are significantly reduced compared with gradient-echo echo-planar imaging.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Gunamony, Dr Shajan
Authors: Budde, J., Shajan, G., Zaitsev, M., Scheffler, K., and Pohmann, R.
College/School:College of Medical Veterinary and Life Sciences > School of Psychology & Neuroscience
Journal Name:Magnetic Resonance in Medicine
ISSN (Online):1522-2594
Published Online:27 February 2013

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