Fast measurement of the quadriceps femoris muscle transverse relaxation time at high magnetic field using segmented echo-planar imaging

2016 ◽  
Vol 45 (2) ◽  
pp. 356-368 ◽  
Author(s):  
Alexandre Fouré ◽  
Guillaume Duhamel ◽  
Christophe Vilmen ◽  
David Bendahan ◽  
Marc Jubeau ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Relaxation Time ◽  
High Magnetic Field ◽  
Transverse Relaxation Time ◽  
Echo Planar Imaging ◽  
Planar Imaging ◽  
Transverse Relaxation ◽  
Quadriceps Femoris Muscle ◽  
Echo Planar ◽  
Femoris Muscle

Snapshot echo-planar imaging methods: current trends and future perspectives

1990 ◽  
Vol 333 (1632) ◽  
pp. 495-506 ◽  
Keyword(s):  
Magnetic Field ◽  
Echo Planar Imaging ◽  
Gradient Coil ◽  
Future Perspectives ◽  
Planar Imaging ◽  
Pixel Resolution ◽  
Matrix Size ◽  
Imaging Methods ◽  
Echo Planar ◽  
Gradient Coil Design

Ultra-high-speed imaging methods have gained in credibility over the past two years by virtue of improvements in imaging quality. This has come about by increases in both signal:noise ratios and image matrix size. Signal:noise improvements have been gained largely by use of higher magnetic field strengths. In echo-planar imaging (EP1) the image matrix size, and hence pixel resolution, depends on the use of large rapidly switched magnetic field gradients. Improvements in gradient coil design, the introduction of active magnetic screening of the coils and the availability of more powerful amplifiers, have all helped to achieve higher in-plane resolution. On our home-built system, operating at 0.5 T, the pixel resolution is currently 3 x 1.5 mm 2 for a slice thickness of ca . 10 mm. The principles of EP1 are briefly outlined and results of current techniques presented. Future perspectives will be directed to combinations of EP1 with spectroscopy and new developments in echo-volumar imaging.

scholarly journals Effect of Mineral Composition on Transverse Relaxation Time Distributions and MR Imaging of Tight Rocks from Offshore Ireland

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 232
Author(s):  
Stian Almenningen ◽  
Srikumar Roy ◽  
Arif Hussain ◽  
John Georg Seland ◽  
Geir Ersland
Keyword(s):  
Magnetic Field ◽  
Relaxation Time ◽  
Mr Imaging ◽  
Field Strength ◽  
High Field ◽  
Transverse Relaxation Time ◽  
Transverse Relaxation ◽  
The Core ◽  
Low Field ◽  
Field Strengths

In this paper, we investigate the effect of magnetic field strength on the transverse relaxation time constant (T2) in six distinct core plugs from four different rock types (three sandstones, one basalt, one volcanic tuff and one siltstone), retrieved from offshore Ireland. The CPMG pulse-sequence was used at two different magnetic field strengths: high-field at 4.70 T and low-field at 0.28 T. Axial images of the core plugs were also acquired with the RAREst sequence at high magnetic field strength. Thin-sections of the core plugs were prepared for optical imaging and SEM analysis, and provided qualitative information on the porosity and quantification of the elemental composition of the rock material. The content of iron varied from 4 wt. % to close to zero in the rock samples. Nevertheless, the effective T2 distributions obtained at low-field were used to successfully predict the porosity of the core plugs. Severe signal attenuations from internal magnetic gradients resulted in an underestimation of the porosity at high-field. No definitive trend was identified on the evolution of discrete relaxation time components between magnetic field strengths. The low-field measurements demonstrate that NMR is a powerful quantitative tool for petrophysical rock analysis as compared to thin-section analysis. The results of this study are of interest to the research community who characterizes natural gas hydrates in tight heterogeneous core plugs, and who typically relies on MR imaging to distinguish between solid hydrates and fluid phases. It further exemplifies the importance of selecting appropriate magnetic field strengths when employing NMR/MRI for porosity calculation in tight rock.

scholarly journals Reduction of magnetic field inhomogeneity artifacts in echo planar imaging with SENSE and GESEPI at high field

2004 ◽  
Vol 52 (6) ◽  
pp. 1418-1423 ◽  
Author(s):  
Qing X. Yang ◽  
Jianli Wang ◽  
Michael B. Smith ◽  
Mark Meadowcroft ◽  
Xiaoyu Sun ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Field ◽  
Echo Planar Imaging ◽  
Magnetic Field Inhomogeneity ◽  
Field Inhomogeneity ◽  
Planar Imaging ◽  
Echo Planar

Concomitant magnetic-field-induced artifacts in axial echo planar imaging

1998 ◽  
Vol 39 (4) ◽  
pp. 596-605 ◽  
Author(s):  
Xiaohong Joe Zhou ◽  
Yiping P. Du ◽  
Matt A. Bernstein ◽  
H. Glenn Reynolds ◽  
Joseph K. Maier ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Echo Planar Imaging ◽  
Planar Imaging ◽  
Echo Planar

Monitoring, analysis, and correction of magnetic field fluctuations in echo planar imaging time series

2014 ◽  
Vol 74 (2) ◽  
pp. 396-409 ◽  
Author(s):  
Lars Kasper ◽  
Saskia Bollmann ◽  
S. Johanna Vannesjo ◽  
Simon Gross ◽  
Maximilian Haeberlin ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Time Series ◽  
Echo Planar Imaging ◽  
Planar Imaging ◽  
Imaging Time ◽  
Field Fluctuations ◽  
Echo Planar

Correction of concomitant magnetic field-induced image artifacts in nonaxial echo-planar imaging

2002 ◽  
Vol 48 (3) ◽  
pp. 509-515 ◽  
Author(s):  
Yiping P. Du ◽  
Xiaohong Joe Zhou ◽  
Matt A. Bernstein
Keyword(s):  
Magnetic Field ◽  
Echo Planar Imaging ◽  
Image Artifacts ◽  
Planar Imaging ◽  
Echo Planar

In Vivo Relaxation Time Measurements in the Human Placenta Using Echo Planar Imaging at 0.5 T

1998 ◽  
Vol 16 (3) ◽  
pp. 241-247 ◽  
Author(s):  
P.A Gowland ◽  
A Freeman ◽  
B Issa ◽  
P Boulby ◽  
K.R Duncan ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Human Placenta ◽  
Echo Planar Imaging ◽  
Planar Imaging ◽  
Echo Planar
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