“…METHODS: The 8Tx‐dipoles/32Rx‐loops coil array was characterized by the SNR, g‐factors, noise correlation matrix, accelerated image quality, and [Formula: see text] maps, and compared with a commercial 1Tx‐birdcage/32Rx‐loops array. Simulated and measured [Formula: see text] maps were shown for the 8Tx‐dipoles/32Rx‐loops coil array and compared with the 8Tx/Rx dipole array. …”
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“…METHODS: Pregnant models in the 3rd, 7th, and 9th months of gestation were used for simulations in a birdcage coil at 3T. Dielectric pads were optimized regions of interest (ROI) using previously developed methods for [Formula: see text] efficiency and homogeneity and were designed for 2 ROIs: the entire fetus and the brain of the fetus. …”
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“…The heating was induced by RF fields in a 1.5 T MRI head birdcage coil (often used for imaging patients with implants) at 64 MHz, and normalized results to 3.2 W/kg whole head average SAR. …”
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“…In this study, we investigate, for a 32‐channel receiver head array at 7 T, if transmitter detuning of a quadrature birdcage or of an eight‐channel transmit coil can be omitted without substantially sacrificing signal‐to‐noise ratio (SNR). …”
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“…Given the same or similar coil settings, the computational human model generates meaningful results for SAR, B1 field, and temperature rise when used in conjunction with the 1.5 T birdcage MRI coils or at higher frequencies corresponding to 3 T MRI. …”
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“…Methods: A numerical model of an RF birdcage body coil and an anatomically realistic virtual patient with a native spatial resolution of 1 mm(3) were used to simulate the in vivo electric field at 64 MHz (1.5 T MRI system). …”
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“…The combined magnetic flux density (||B(1)||) distributions of four configurations of PA coils—4-, 8-, 12-, and 16-channel Rx-only mode under the local transmit (Tx) mode of birdcage coils—were evaluated using electromagnetic (EM) calculations. …”
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“…METHODS: Exposure from a 297‐MHz birdcage head transmit coil (CP mode single‐channel transmission) was simulated in several child models (ages 3–14, mass 13.9–50.4 kg) and one adult, using time‐domain electromagnetic and thermal solvers. …”
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“…Experiments were carried out with the exact same type of birdcage volume coil (except at 3 T, where a similar coil was used) to attempt at isolating the evolution of SNR with field strength alone. …”
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“…Thanks to electromagnetic resonances and the Kerker effect, it is possible to redistribute and reshape the RF electromagnetic field in a birdcage antenna.</p> <p class="MsoBodyText">We will also show how these concepts could be used for other types of applications such as waterwave cloaking or seismic protection.…”
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“…RESULTS: From the finite-difference-time-domain (FDTD) electromagnetic field simulations with a human body model placed in a birdcage coil operating at 3 T, it was observed that the RF pulse calibration with iterative cost function minimization can give improvement of B(1) field uniformity as well as flip-angle calibration. …”
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“…Power deposition and temperature rise (ΔT) were evaluated with the model positioned in a whole-body birdcage RF coil in the presence of a tES setup. Multiphysics modeling at 3T (123.2 MHz) on unstructured meshes was based on RF circuit, 3D electromagnetic, and thermal co-simulations. …”
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“…To obtain 3D (31)P MRSI spectra with improved signal‐to‐noise ratio on clinical 3 T MR systems, we used a coil combination consisting of a dual‐tuned birdcage transmit coil and a (31)P eight‐channel phased‐array receive insert. …”
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“…RESULTS: We present a 72-year-old male with a history of JAK-2-positive polycythemia vera with secondary myelofibrosis, and concurrent multiple myeloma who presented with 3 weeks of chronic cough and 3 days of fever with severe bifrontal headache after remodeling a large birdcage in his backyard. The patient was on ruxolitinib, ixazomib, and weekly dexamethasone. …”
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