scholarly journals Sensitivity-encoded single-shot spiral imaging for reduced susceptibility artifacts in BOLD fMRI

2002 ◽  
Vol 48 (5) ◽  
pp. 860-866 ◽  
Author(s):  
Markus Weiger ◽  
Klaas P. Pruessmann ◽  
Robert Österbauer ◽  
Peter Börnert ◽  
Peter Boesiger ◽  
...  
Keyword(s):  
Single Shot ◽  
Spiral Imaging ◽  
Susceptibility Artifacts ◽  
Bold Fmri

Single‐shot spiral imaging enabled by an expanded encoding model: D emonstration in diffusion MRI

2016 ◽  
Vol 77 (1) ◽  
pp. 83-91 ◽  
Author(s):  
Bertram J. Wilm ◽  
Christoph Barmet ◽  
Simon Gross ◽  
Lars Kasper ◽  
S. Johanna Vannesjo ◽  
...  
Keyword(s):  
Diffusion Mri ◽  
Single Shot ◽  
Spiral Imaging

Single-shot dual-z-shimmed sensitivity-encoded spiral-in/out imaging for functional MRI with reduced susceptibility artifacts

2007 ◽  
Vol 59 (1) ◽  
pp. 221-227 ◽  
Author(s):  
Trong-Kha Truong ◽  
Allen W. Song
Keyword(s):  
Functional Mri ◽  
Single Shot ◽  
Susceptibility Artifacts

scholarly journals Ultrafast bold fMRI using single-shot spin-echo echo planar imaging

2009 ◽  
Vol 34 (1) ◽  
pp. 37 ◽  
Author(s):  
Said Boujraf ◽  
Paul Summers ◽  
Faouzi Belahsen ◽  
Klaas Prussmann ◽  
Spyros Kollias
Keyword(s):  
Spin Echo ◽  
Echo Planar Imaging ◽  
Single Shot ◽  
Planar Imaging ◽  
Bold Fmri ◽  
Echo Planar

scholarly journals Single‐shot spiral imaging at 7  T

2018 ◽  
Vol 80 (5) ◽  
pp. 1836-1846 ◽  
Author(s):  
Maria Engel ◽  
Lars Kasper ◽  
Christoph Barmet ◽  
Thomas Schmid ◽  
Laetitia Vionnet ◽  
...  
Keyword(s):  
Single Shot ◽  
Spiral Imaging

scholarly journals Spiral-in/out BOLD fMRI for increased SNR and reduced susceptibility artifacts

2001 ◽  
Vol 46 (3) ◽  
pp. 515-522 ◽  
Author(s):  
Gary H. Glover ◽  
Christine S. Law
Keyword(s):  
Susceptibility Artifacts ◽  
Bold Fmri

Reduced susceptibility artifacts in BOLD fMRI using localized shimming

NeuroImage ◽  
2000 ◽  
Vol 11 (5) ◽  
pp. S553 ◽  
Author(s):  
Hui Mao ◽  
Srinivas Kidambi
Keyword(s):  
Susceptibility Artifacts ◽  
Bold Fmri

scholarly journals Functional Activities Detected in the Olfactory Bulb and Associated Olfactory Regions in the Human Brain Using T2-Prepared BOLD Functional MRI at 7T

2021 ◽  
Vol 15 ◽  
Author(s):  
Xinyuan Miao ◽  
Adrian G. Paez ◽  
Suraj Rajan ◽  
Di Cao ◽  
Dapeng Liu ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Orbitofrontal Cortex ◽  
Brain Regions ◽  
Vital Role ◽  
Blood Oxygenation ◽  
Olfactory Stimulation ◽  
Planar Imaging ◽  
Susceptibility Artifacts ◽  
Bold Fmri ◽  
Susceptibility Effects

Olfaction is a fundamental sense that plays a vital role in daily life in humans, and can be altered in neuropsychiatric and neurodegenerative diseases. Blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) using conventional echo-planar-imaging (EPI) based sequences can be challenging in brain regions important for olfactory processing, such as the olfactory bulb (OB) and orbitofrontal cortex, mainly due to the signal dropout and distortion artifacts caused by large susceptibility effects from the sinonasal cavity and temporal bone. To date, few studies have demonstrated successful fMRI in the OB in humans. T2-prepared (T2prep) BOLD fMRI is an alternative approach developed especially for performing fMRI in regions affected by large susceptibility artifacts. The purpose of this technical study is to evaluate T2prep BOLD fMRI for olfactory functional experiments in humans. Olfactory fMRI scans were performed on 7T in 14 healthy participants. T2prep BOLD showed greater sensitivity than GRE EPI BOLD in the OB, orbitofrontal cortex and the temporal pole. Functional activation was detected using T2prep BOLD in the OB and associated olfactory regions. Habituation effects and a bi-phasic pattern of fMRI signal changes during olfactory stimulation were observed in all regions. Both positively and negatively activated regions were observed during olfactory stimulation. These signal characteristics are generally consistent with literature and showed a good intra-subject reproducibility comparable to previous human BOLD fMRI studies. In conclusion, the methodology demonstrated in this study holds promise for future olfactory fMRI studies in the OB and other brain regions that suffer from large susceptibility artifacts.

scholarly journals Integration of a radiofrequency coil and commercial field camera for ultra-high-field MRI

2021 ◽  
Author(s):  
Kyle M Gilbert ◽  
Paul Dubovan ◽  
Joseph S Gati ◽  
Ravi S Menon ◽  
Corey A Baron
Keyword(s):  
High Field ◽  
Field Monitoring ◽  
Gradient Coil ◽  
Single Shot ◽  
Rf Coil ◽  
Space Trajectories ◽  
Ultra High Field ◽  
Spiral Imaging ◽  
Before And After ◽  
Commercial Field

Purpose: To develop an RF coil with an integrated commercial field camera for ultra-high field (7 T) neuroimaging. The RF coil will operate within a head-only gradient coil and be subject to the corresponding design constraints. The RF coil can thereafter be used for subject-specific correction of k-space trajectories-notably in gradient-sensitive sequences such as single-shot spiral imaging. Methods: The transmit and receive performance was evaluated before and after the integration of field probes, while field probes were evaluated when in an optimal configuration external to the coil and after their integration. Diffusion-weighted EPI and single-shot spiral acquisitions were employed to evaluate the efficacy of correcting higher order field perturbations and the consequent effect on image quality. Results: Field probes had a negligible effect on RF-coil performance, including the transmit efficiency, transmit uniformity, and mean SNR over the brain. Modest reductions in field-probe signal lifetimes were observed, caused primarily by non-idealities in the gradient and shim fields of the head-only gradient coil at the probe positions. The field monitoring system could correct up to second-order field perturbations in single-shot spiral imaging. Conclusion: The integrated RF coil and field camera was capable of concurrent field monitoring within a 7T head-only scanner and facilitated the subsequent correction of k-space trajectories during spiral imaging.

scholarly journals Advances in Spiral fMRI: A High-resolution Study with Single-shot Acquisition

2019 ◽  
Author(s):  
Lars Kasper ◽  
Maria Engel ◽  
Jakob Heinzle ◽  
Matthias Mueller-Schrader ◽  
Nadine N. Graedel ◽  
...  
Keyword(s):  
Image Reconstruction ◽  
Static Field ◽  
7 Tesla ◽  
List Type ◽  
Single Shot ◽  
Planar Imaging ◽  
Spatiotemporal Resolution ◽  
Signal Model ◽  
Spiral Imaging ◽  
Spiral Readout

AbstractSpiral fMRI has been put forward as a viable alternative to rectilinear echo-planar imaging, in particular due to its enhanced average k-space speed and thus high acquisition efficiency. This renders spirals attractive for contemporary fMRI applications that require high spatiotemporal resolution, such as laminar or columnar fMRI. However, in practice, spiral fMRI is typically hampered by its reduced robustness and ensuing blurring artifacts, which arise from imperfections in both static and dynamic magnetic fields.Recently, these limitations have been overcome by the concerted application of an expanded signal model that accounts for such field imperfections, and its inversion by iterative image reconstruction. In the challenging ultra-high field environment of 7 Tesla, where field inhomogeneity effects are aggravated, both multi-shot and single-shot 2D spiral imaging at sub-millimeter resolution was demonstrated with high depiction quality and anatomical congruency.In this work, we further these advances towards a time series application of spiral readouts, namely, single-shot spiral BOLD fMRI at 0.8 mm in-plane resolution. We demonstrate that spiral fMRI at 7 T is not only feasible, but delivers both competitive image quality and BOLD sensitivity, with a spatial specificity of the activation maps that is not compromised by artifactual blurring. Furthermore, we show the versatility of the approach with a combined in/out spiral readout at a more typical resolution (1.5 mm), where the high acquisition efficiency allows to acquire two images per shot for improved sensitivity by echo combination.HighlightsThis work reports the first fMRI study at 7T with spiral readout gradient waveforms.We achieve spiral fMRI with sub-millimeter resolution (0.8 mm, in-plane FOV 230 mm), acquired in a single shot.Spiral images exhibit intrinsic geometric congruency to anatomical scans, and spatially highly specific activation patterns.Image reconstruction rests on a signal model expanded by measured trajectories and static field maps, inverted by cg-SENSE.We assess generalizability of the approach for spiral in/out readouts, providing two images per shot (1.5 mm resolution).

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