Spelling suggestions: "subject:"radiofrequency soils""
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Measurement of physiological parameters with echo-planar imagingFreeman, Alan John January 1995 (has links)
No description available.
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Radiofrequency Coils for Faster and Quieter MR Imaging on a Neonatal MR SystemIreland, Christopher M. 15 October 2020 (has links)
No description available.
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Design of Radiofrequency Coils for Magnetic Resonance Imaging Applications: A Computational Electromagnetic ApproachIBrahim, Tamer S. 29 January 2003 (has links)
No description available.
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Achieving Invisible Balance: Utilizing Novel Elliptical Traps for Improved Radiofrequency Coil Thermodynamic Stability, Minimized Field Distortion, and Common-Mode Current SuppressionJana Vincent (10711377) 29 April 2021 (has links)
<p>Advances in Magnetic Resonance Imaging (MRI) have been made
possible through increased field strengths and innovations in radiofrequency
(RF) coils. With increasing field strengths, unique challenges are presented in
RF coil development, namely the suppression of common-mode currents present
along the shields of the cabling that connect the RF coil to the MR scanner.
These currents can lead to coupling with the coil, resulting in a reduction of
coil sensitivity and signal-to-noise ratio. These currents can induce local
electric fields that beyond a certain level can exceed SAR limits and even
cause patient burns. Several cable trap designs exist to help address this
problem; however, many of the existing designs, such as bazooka cable traps,
are rigid and bulky. This leads to increased overall coil weight and impedes
the flexibility of the cable. Improving upon these designs, a small,
3D-printed, lightweight elliptical cable trap is presented. The unique geometry
makes it invisible to the MR scanner while maintaining significant mutual
inductance that can produce up to 380 Ω on the cable. These structures were
wrapped with stranded wire containing four breaks for tuning capacitors. 60 of
these elliptical cable traps were placed along the length of a 139-cm cable,
replacing the standard 4 bazooka cable traps. The results of B<sub>1</sub>
distortion and heating tests showed that these elliptical baluns improve RF
coil thermodynamic stability, produce less B<sub>1</sub> distortion, and reduce
overall coil weight and bulk compared to a cable with four bazooka traps.
</p>
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Stretching the Boundaries of Radiofrequency Coil Design For MRI: Innovations in Lightweight, Flexible, and Stretchable Designs for Enhanced Patient Comfort and Image QualityJana Vincent (10711377) 29 April 2021 (has links)
<p>There have been several advancements in
radiofrequency (RF) coil development for magnetic resonance imaging (MRI) to
improve both image quality and patient comfort. Notable to these improvements
is the trend towards lightweight and flexible coils allowing for the
conformation around a variety of anatomies and body sizes. This allows for a
more comfortable patient experience and enhanced signal reception. Despite
these improvements, flexible supine coils for dedicated breast imaging, or
larger stretchable coil arrays for closer proximity of placement and imaging at
degrees of flexion, are not available. Conventional breast coils are rigid and
typically require prone positioning which creates uncomfortable pressure points
along the sternum. Also, these coils do not encompass the axilla or areas in
the upper chest wall. Additionally, surgical planning is performed in the
supine position, making it challenging to localize lesions from prone MRI
scans. To address these issues, two novel RF coil technologies are presented.
Firstly, a flexible, lightweight, 60-channel supine breast coil has been
constructed. This coil provides shorter scan times, greater coverage of the
breasts, axilla, upper chest wall, and torso while also providing enhanced
patient comfort over conventional breast coils. The second RF coil technology
is a 20-channel stretchable, multipurpose coil. This coil addresses limitations
of conformability around curved surfaces while allowing for the imaging of
joints at a bend. Due to the stretchability, this coil exhibited enhanced
signal and image quality for a variety of body sizes and anatomies, such as
ankles and wrists, when compared to a flexible commercial coil.</p>
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