Fellner, Claudia and Doenitz, C. and Finkenzeller, T. and Jung, E. M. and Rennert, J. and Schlaier, J. (2009) Improving the spatial accuracy in functional magnetic resonance imaging (fMRI) based on the blood oxygenation level dependent (BOLD) effect: Benefits from parallel imaging and a 32-channel head array coil at 1.5 Tesla. CLINICAL HEMORHEOLOGY AND MICROCIRCULATION, 43 (1-2). pp. 71-82. ISSN 1386-0291,
Full text not available from this repository. (Request a copy)Abstract
Geometric distortions and low spatial resolution are current limitations in functional magnetic resonance imaging (fMRI). The aim of this study was to evaluate if application of parallel imaging or significant reduction of voxel size in combination with a new 32-channel head array coil can reduce those drawbacks at 1.5 T for a simple hand motor task. Therefore, maximum t-values (t(max)) in different regions of activation, time-dependent signal-to-noise ratios (SNR(t)) as well as distortions within the precentral gyrus were evaluated. Comparing fMRI with and without parallel imaging in 17 healthy subjects revealed significantly reduced geometric distortions in anterior-posterior direction. Using parallel imaging, tmax only showed a mild reduction (7-11%) although SNR(t) was significantly diminished (25%). In 7 healthy subjects high-resolution (2 x 2 x 2 mm(3)) fMRI was compared with standard fMRI (3 x 3 x 3 mm(3)) in a 32-channel coil and with high-resolution fMRI in a 12-channel coil. The new coil yielded a clear improvement for t(max) (21-32%) and SNR(t) (51%) in comparison with the 12-channel coil. Geometric distortions were smaller due to the smaller voxel size. Therefore, the reduction in t(max) (8-16%) and SNR(t) (52%) in the high-resolution experiment seems to be tolerable with this coil. In conclusion, parallel imaging is an alternative to reduce geometric distortions in fMRI at 1.5 T. Using a 32-channel coil, reduction of the voxel size might be the preferable way to improve spatial accuracy.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | HIGH-RESOLUTION FMRI; HUMAN BRAIN; ACQUISITIONS GRAPPA; MRI; SENSE; EPI; FIELDS; 3T; fMRI; BOLD; parallel imaging; spatial resolution; array coil |
| Subjects: | 600 Technology > 610 Medical sciences Medicine |
| Divisions: | Medicine > Lehrstuhl für Neurochirurgie Medicine > Lehrstuhl für Röntgendiagnostik |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 12 Oct 2020 07:12 |
| Last Modified: | 12 Oct 2020 07:12 |
| URI: | https://pred.uni-regensburg.de/id/eprint/29683 |
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