Journal ArticleDOI
128‐channel body MRI with a flexible high‐density receiver‐coil array
Christopher J. Hardy,Randy Otto John Giaquinto,Joseph Edward Piel,Kenneth William Rohling,Luca Marinelli,Daniel J. Blezek,Eric Fiveland,Robert David Darrow,Thomas K. F. Foo +8 more
TLDR
To determine whether the promise of high‐density many‐coil MRI receiver arrays for enabling highly accelerated parallel imaging can be realized in practice, a large number of experiments have been conducted with high-density receiver arrays in order to demonstrate the ability of these arrays to accommodate large numbers of patients.Abstract:
Purpose
To determine whether the promise of high-density many-coil MRI receiver arrays for enabling highly accelerated parallel imaging can be realized in practice.
Materials and Methods
A 128-channel body receiver-coil array and custom MRI system were developed. The array comprises two clamshells containing 64 coils each, with the posterior array built to maximize signal-to-noise ratio (SNR) and the anterior array design incorporating considerations of weight and flexibility as well. Phantom imaging and human body imaging were performed using a variety of reduction factors and 2D and 3D pulse sequences.
Results
The ratio of SNR relative to a 32-element array of similar footprint was 1.03 in the center of an elliptical loading phantom and 1.7 on average in the outer regions. Maximum g-factors dropped from 5.5 (for 32 channels) to 2.0 (for 128 channels) for 4 × 4 acceleration and from 25 to 3.3 for 5 × 5 acceleration. Residual aliasing artifacts for a right/left (R/L) reduction factor of 8 in human body imaging were significantly reduced relative to the 32-channel array.
Conclusion
MRI with a large number of receiver channels enables significantly higher acceleration factors for parallel imaging and improved SNR, provided losses from the coils and electronics are kept negligible. J. Magn. Reson. Imaging 2008;28:1219–1225. © 2008 Wiley-Liss, Inc.read more
Citations
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Journal ArticleDOI
96-Channel Receive-Only Head Coil for 3 Tesla: Design Optimization and Evaluation
Graham Wiggins,Jonathan R. Polimeni,Andreas Potthast,Melanie Schmitt,Vijay Alagappan,Lawrence L. Wald,Lawrence L. Wald +6 more
TL;DR: The benefits and challenges of highly parallel array coils for head imaging were investigated through the development of a 3T receive‐only phased‐array head coil with 96 receive elements constructed on a close‐fitting helmet‐shaped former, with particular attention to sources of signal‐to‐noise ratio (SNR) loss.
Journal ArticleDOI
A 128-Channel Receive-Only Cardiac Coil for Highly Accelerated Cardiac MRI at 3 Tesla
Melanie Schmitt,Andreas Potthast,David E. Sosnovik,Jonathan R. Polimeni,Graham Wiggins,Christina Triantafyllou,Christina Triantafyllou,Lawrence L. Wald,Lawrence L. Wald +8 more
TL;DR: The ability of the 128‐channel coil to facilitate highly accelerated cardiac imaging was demonstrated in four volunteers using acceleration factors up to seven‐fold (R = 7) in a single spatial dimension.
Journal ArticleDOI
Massively parallel MRI detector arrays.
TL;DR: The theoretical and experimental basis for the trend towards higher channel counts relying on insights gained from modeling and experimental studies as well as the theoretical analysis of the so-called "ultimate" SNR and g-factor is reviewed.
Journal ArticleDOI
White Matter fMRI Activation Cannot Be Treated as a Nuisance Regressor: Overcoming a Historical Blind Spot.
Lukas A. Grajauskas,Lukas A. Grajauskas,Lukas A. Grajauskas,Tory Frizzell,Tory Frizzell,Xiaowei Song,Xiaowei Song,Ryan C.N. D'Arcy +7 more
TL;DR: Despite past controversies, increasing evidence has led to acceptance that white matter activity is detectable using functional magnetic resonance imaging (fMRI), and advanced analytic methods continue to be published that reinforce a historic bias against white matter activation by using it as a nuisance regressor.
Journal ArticleDOI
A single-chip array of NMR receivers.
TL;DR: The first single-chip array of integrated NMR receivers for parallel spectroscopy and imaging is presented, composed of eight separate channels, with each channel consisting of a detection coil, a tuning capacitor, a low noise amplifier and a 50 ohm buffer.
References
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PatentDOI
SENSE: Sensitivity Encoding for fast MRI
TL;DR: The problem of image reconstruction from sensitivity encoded data is formulated in a general fashion and solved for arbitrary coil configurations and k‐space sampling patterns and special attention is given to the currently most practical case, namely, sampling a common Cartesian grid with reduced density.
Journal ArticleDOI
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Mark A. Griswold,Peter M. Jakob,Robin M. Heidemann,Mathias Nittka,Vladimir Jellus,Jianmin Wang,Berthold Kiefer,Axel Haase +7 more
TL;DR: This technique, GeneRalized Autocalibrating Partially Parallel Acquisitions (GRAPPA) is an extension of both the PILS and VD‐AUTO‐SMASH reconstruction techniques and provides unaliased images from each component coil prior to image combination.
Journal ArticleDOI
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TL;DR: Methods for simultaneously acquiring and subsequently combining data from a multitude of closely positioned NMR receiving coils are described, conceptually similar to phased array radar and ultrasound and hence the techniques are called the “NMR phased array.”
PatentDOI
Simultaneous acquisition of spatial harmonics (SMASH): ultra-fast imaging with radiofrequency coil arrays
TL;DR: SiMultaneous Acquisition of Spatial Harmonics (SMASH) as mentioned in this paper is a partially parallel imaging strategy, which is readily integrated with many existing fast imaging sequences, yielding multiplicative time savings without a significant sacrifice in spatial resolution or signal-to-noise ratio.
Journal ArticleDOI
Fast spin echo sequences with very long echo trains: design of variable refocusing flip angle schedules and generation of clinical T2 contrast.
TL;DR: This work presents a streamlined technique to generate a sequence of refocusing flip angles on a per‐prescription basis that produces relatively high SNR and limits blurring in a wide range of materials encountered in vivo.