Results 151 to 160 of about 24,328 (188)

Dielectric Resonance Phenomena in Ultra High Field MRI

Journal of Computer Assisted Tomography, 1999
Dielectric resonances have previously been advanced as a significant cause of image degradation at higher fields. In this work, a study of dielectric resonances in ultra high field MRI is presented to explore the real importance of dielectric resonances in the human brain in this setting.Gradient-recalled echo images were acquired using a transverse ...
A, Kangarlu, B A, Baertlein, R, Lee, T, Ibrahim, L, Yang, A M, Abduljalil, P M, Robitaille   +6 more
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Present and Future of Ultra-High Field MRI in Neurodegenerative Disorders

Current Neurology and Neuroscience Reports, 2018
With a high signal-to-noise ratio, unparalleled spatial resolution, and improved contrasts, ultra-high field MR (≥ 7 T) has great potential in depicting the normal radiological anatomy of smaller structures in the brain and can also provide more information about morphological, quantitative, and metabolic changes associated with a wide range of brain ...
Donatelli, Graziella, Ceravolo, Roberto, Frosini, Daniela, Tosetti, Michela, Bonuccelli, Ubaldo, Cosottini, Mirco   +5 more
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Threats to ultra-high-field MRI

Physics World, 2009
In 2004 the European Commission (EC) adopted a directive restricting occupational exposure to electromagnetic fields. This directive (2004/40/CE), which examines the possible health risks of the electromagnetic fields from mobile phones, Wi-Fi, Bluetooth and other devices, concluded that upper limits on radiation and applied electromagnetic fields are ...
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A Coaxial RF Applicator for Ultra-High Field Human MRI

IEEE Transactions on Biomedical Engineering, 2019
To develop a novel radio-frequency (RF) concept for ultra-high field (UHF) human magnetic resonance imaging (MRI) based on a coaxial resonant cavity.A two-channel slotted coaxial cavity RF applicator was designed for human head MRI at 9.4T. Physical dimensions made the proposed conducting structure resonant at the required frequency without tuning ...
Georgiy Solomakha, Anna E. Andreychenko, Pierre-François van de Moortele, H. Kroeze, Alexander J. Raaijmakers, F. E. Euwe, Jan J. W. Lagendijk, Peter R. Luijten, Cornelis A. T. van den Berg   +8 more
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Clinical application of high and ultra high-field MRI

Brain and Development, 2007
The 21st century ushered in the century of human beings. The previous era characterized by the chase after super technology has been replaced by a new era which focuses on the meaning of human existence and quality of life. Clinical practice has accordingly also undergone rapid change. Amongst the many competing technologies, clearly magnetic resonance
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Gradients in Ultra High Field (UHF) MRI

2011
The gradients are one of the three magnetic field generating units that are necessary to make MRI work. While the other two types of fields are directly affected by the strength of the main magnet—the static magnetic field, B o , and the RF (radio frequency) fields by the Larmor frequency depending linear on the static magnetic field strength—the same ...
Peter Dietz, Franz Schmitt, Jürgen Hennig   +2 more
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Contrast-enhanced ultra-high-field liver MRI: A feasibility trial

European Journal of Radiology, 2013
The aim of this study was to investigate the feasibility of dynamic contrast-enhanced 7 T MRI of the liver using an eight-channel radiofrequency (RF) transmit/receive body-coil. 16 healthy subjects were examined on a 7 T MR system utilizing a custom-built eight-channel RF body-coil suitable for RF-shimming.
Umutlu, Lale, Bitz, Andreas K., Maderwald, Stefan, Orzada, Stephan, Kinner, Sonja, Kraff, Oliver, Brote, Irina, Ladd, Susanne, Schröder, Tobias, Forsting, Michael, Antoch, Gerald, Ladd, Mark E., Quick, Harald H., Lauenstein, Thomas   +13 more
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Challenges and Opportunities of Ultra-High Field MRI

2010
Magnetic resonance imaging (MRI) and spectroscopy (MRS) have contributed considerably to our understanding of the structure and function of the human brain, and are essential in modern radiological practice. The development and applications of MRI systems at fields of 7 Tesla and above provide many new opportunities and technical challenges.
A. N. Dula, E. B. Welch, J. L. Creasy, J. C. Gatenby, E. A. Stringer, L. M. Chen, A. W. Anderson, M. J. Avison, J. C. Gore   +8 more
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RF safety assessment in ultra-high field MRI

2023
The radiofrequency (RF) safety constraints remain a major factor limiting the quality and speed of ultra-high field magnetic resonance imaging (UHF-MRI) and the use of parallel transmission (pTx) technology. Since the local Specific Absorption Rate (SAR) cannot be measured during an MRI examination, it is usually evaluated by off-line electromagnetic ...
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Ultra-high field magnets for whole-body MRI

Superconductor Science and Technology, 2016
For whole-body MRI, an ultra-high field (UHF) magnet is currently defined as a system operating at 7 T or above. Over 70 UHF magnets have been built, all with the same technical approach originally developed by Magnex Scientific Ltd. The preferred coil configuration is a compensated solenoid.
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