Enhancement of temporal resolution and BOLD sensitivity in real-time fMRI using multi-slab echo-volumar imaging
| Autor: | Oliver Speck, Radu Mutihac, Elena S. Ackley, Cristina Murray-Krezan, Jochen Rick, Maxim Zaitsev, Stefan Posse, Matthew S. Shane |
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| Rok vydání: | 2012 |
| Předmět: |
Visual perception
Cognitive Neuroscience Prefrontal Cortex Signal-To-Noise Ratio Auditory cortex Brain mapping Article Image Processing Computer-Assisted medicine Humans Computer vision Visual Cortex Auditory Cortex Physics Brain Mapping Resting state fMRI Echo-Planar Imaging business.industry Motor Cortex Brain Heart Magnetic Resonance Imaging Oxygen Communication noise Visual cortex medicine.anatomical_structure Neurology Data Interpretation Statistical Temporal resolution Linear Models Respiratory Mechanics Visual Perception Artificial intelligence Artifacts business Algorithms Psychomotor Performance Software Motor cortex Biomedical engineering |
| Zdroj: | NeuroImage. 61:115-130 |
| ISSN: | 1053-8119 |
| Popis: | In this study, a new approach to high-speed fMRI using multi-slab echo-volumar imaging (EVI) is developed that minimizes geometrical image distortion and spatial blurring, and enables nonaliased sampling of physiological signal fluctuation to increase BOLD sensitivity compared to conventional echo-planar imaging (EPI). Real-time fMRI using whole brain 4-slab EVI with 286 ms temporal resolution (4 mm isotropic voxel size) and partial brain 2-slab EVI with 136 ms temporal resolution (4 × 4 × 6 mm3 voxel size) was performed on a clinical 3 Tesla MRI scanner equipped with 12-channel head coil. Four-slab EVI of visual and motor tasks significantly increased mean (visual: 96%, motor: 66%) and maximum t-score (visual: 263%, motor: 124%) and mean (visual: 59%, motor: 131%) and maximum (visual: 29%, motor: 67%) BOLD signal amplitude compared with EPI. Time domain moving average filtering (2 s width) to suppress physiological noise from cardiac and respiratory fluctuations further improved mean (visual: 196%, motor: 140%) and maximum (visual: 384%, motor: 200%) t-scores and increased extents of activation (visual: 73%, motor: 70%) compared to EPI. Similar sensitivity enhancement, which is attributed to high sampling rate at only moderately reduced temporal signal-to-noise ratio (mean: − 52%) and longer sampling of the BOLD effect in the echo-time domain compared to EPI, was measured in auditory cortex. Two-slab EVI further improved temporal resolution for measuring task-related activation and enabled mapping of five major resting state networks (RSNs) in individual subjects in 5 min scans. The bilateral sensorimotor, the default mode and the occipital RSNs were detectable in time frames as short as 75 s. In conclusion, the high sampling rate of real-time multi-slab EVI significantly improves sensitivity for studying the temporal dynamics of hemodynamic responses and for characterizing functional networks at high field strength in short measurement times. |
| Databáze: | OpenAIRE |
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