96‐Channel receive‐only head coil for 3 Tesla: Design optimization and evaluation

Wiggins, Graham C.; Polimeni, Jon̈athan R.; Potthast, Andreas; Schmitt, Mélanie; Alagappan, Vijay; Wald, Lawrence L.

doi:10.1002/mrm.22028

Cited by 244 publications

(293 citation statements)

References 20 publications

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“…Inspecting the tSNR of the same voxels assessed by the fMRI investigation revealed higher values for the 32-channel coil, in line with the high SNR of a 32-channel array reported by Wiggins et al (4,5). Applying a prescan normalization filter also increased the observed tSNR over both coils, presumably because this kind of filtering evened out the original image intensity inhomogeneities.…”

Section: Discussionsupporting

confidence: 83%

Comparison of a 32‐channel with a 12‐channel head coil: Are there relevant improvements for functional imaging?

Kaza

Klose²,

Lotze

2011

Magnetic Resonance Imaging

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Purpose: To evaluate the suitability of a 12-or 32-channel head coil and of a prescan normalization filter for functional magnetic resonance imaging (fMRI) studies at different brain regions.Materials and Methods: fMRI was obtained from 36 volunteers executing a visually instructed motor paradigm using a 12-channel head matrix coil and a 32-channel phased-array head coil with and without prescan normalization filtering at 3 T. The time-course signal-to-noise ratio (tSNR) and the magnitude of functional activation (betavalue, t-value, percent signal change) were statistically compared between experimental conditions for the contralateral primary motor and visual cortex, contralateral thalamus, and ipsilateral anterior cerebellar hemispheres.Results: tSNR was higher overall measuring with the 32-channel array and with prescan normalization. Without filtering, the 32-channel array delivered higher functional activation magnitudes for the visual cortex, whereas the 12-channel array seemed superior in this respect in thalamus and cerebellum. Filtering did not considerably affect the fMRI-activation magnitude detected from the 12-channel coil; its application favored the 32-channel coil at the subcortical and cerebellar locations but disfavored it at the cortical ones. Conclusion:The 32-channel coil detected more fMRI-activation cortically but less subcortically than the 12-channel coil; prescan normalization improved activation parameters only at central brain structures.

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Section: Discussionsupporting

confidence: 83%

Comparison of a 32‐channel with a 12‐channel head coil: Are there relevant improvements for functional imaging?

Kaza

Klose²,

Lotze

2011

Magnetic Resonance Imaging

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“…The reason for striving for stronger gradients is twofold, (a) it permits sampling of images at high b-values with shorter diffusion encoding times, which will improve angular resolution and (b) a shorter diffusion sensitizing gradient duration helps to decrease the echo time, which further boosts the SNR. Multichannel coil technology with at least 32 (and up to 128) channels will not only help to increase SNR but also reduce the acquisition time when combined with fast imaging methods such as parallel imaging and multiple slice encoding pulse sequences (Reese et al, 2009;Wiggins et al, 2009). This will ultimately allow increased spatial resolution and decrease the susceptibility artifacts inherent to echo planar imaging.…”

Section: Challenges and Perspectivesmentioning

confidence: 99%

MR connectomics: Principles and challenges

Hagmann

Cammoun

Gigandet

et al. 2010

Journal of Neuroscience Methods

255

207

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a b s t r a c t MR connectomics is an emerging framework in neuro-science that combines diffusion MRI and whole brain tractography methodologies with the analytical tools of network science. In the present work we review the current methods enabling structural connectivity mapping with MRI and show how such data can be used to infer new information of both brain structure and function. We also list the technical challenges that should be addressed in the future to achieve high-resolution maps of structural connectivity. From the resulting tremendous amount of data that is going to be accumulated soon, we discuss what new challenges must be tackled in terms of methods for advanced network analysis and visualization, as well data organization and distribution. This new framework is well suited to investigate key questions on brain complexity and we try to foresee what fields will most benefit from these approaches.

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“…Conformal coil designs have the potential to increase transmit efficiency, thereby decreasing the specific absorption rate (SAR). Additionally, the close proximity between coil elements and the head produces an increase in receive sensitivity that is analogous to that of a conformal receive-only array (16,17). The constraint on conformal coils is that they must still achieve sufficient transmit-field uniformity over the imaging region, as discussed earlier.…”

mentioning

confidence: 99%

A conformal transceive array for 7 T neuroimaging

Gilbert

Belliveau

Curtis

et al. 2011

Magnetic Resonance in Med

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The first 16-channel transceive surface-coil array that conforms to the human head and operates at 298 MHz (7 T) is described. Individual coil elements were decoupled using circumferential shields around each element that extended orthogonally from the former. This decoupling method allowed elements to be constructed with arbitrary shape, size, and location to create a three-dimensional array. Radiofrequency shimming achieved a transmit-field uniformity of 20% over the whole brain and 14% over a single axial slice. During radiofrequency transmission, coil elements couple tightly to the head and reduce the amount of power necessary to achieve a mean 90°flip angle (660-ms and 480-ms pulse lengths were required for a 1-kW hard pulse when shimming over the whole brain and a single axial slice, respectively). During reception, the close proximity of coil elements to the head increases the signal-to-noise ratio in the periphery of the brain, most notably at the superior aspect of the head. The sensitivity profile of each element is localized beneath the respective shield. When combined with the achieved isolation between elements, this results in the capacity for low geometry factors during both transmit and receive: 1.04/1.06 (mean) and 1.25/1.54 (maximum) for 3-by-3 acceleration in the axial/sagittal plane. High cortical signal-tonoise ratio and parallel imaging performance make the conformal coil ideal for the study of high temporal and/or spatial cortical architecture and function.

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96‐Channel receive‐only head coil for 3 Tesla: Design optimization and evaluation

Cited by 244 publications

References 20 publications

Comparison of a 32‐channel with a 12‐channel head coil: Are there relevant improvements for functional imaging?

Comparison of a 32‐channel with a 12‐channel head coil: Are there relevant improvements for functional imaging?

MR connectomics: Principles and challenges

A conformal transceive array for 7 T neuroimaging

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