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Radiofrequency antenna concepts for human cardiac MR at 14.0 T

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Item Type:Article
Title:Radiofrequency antenna concepts for human cardiac MR at 14.0 T
Creators Name:Nurzed, B. and Kuehne, A. and Aigner, C.S. and Schmitter, S. and Niendorf, T. and Eigentler, T.W.
Abstract:OBJECTIVE: To examine the feasibility of human cardiac MR (CMR) at 14.0 T using high-density radiofrequency (RF) dipole transceiver arrays in conjunction with static and dynamic parallel transmission (pTx). MATERIALS AND METHODS: RF arrays comprised of self-grounded bow-tie (SGBT) antennas, bow-tie (BT) antennas, or fractionated dipole (FD) antennas were used in this simulation study. Static and dynamic pTx were applied to enhance transmission field (B(1)(+)) uniformity and efficiency in the heart of the human voxel model. B(1)(+) distribution and maximum specific absorption rate averaged over 10 g tissue (SAR(10g)) were examined at 7.0 T and 14.0 T. RESULTS: At 14.0 T static pTx revealed a minimum B(1)(+)(ROI) efficiency of 0.91 μT/√kW (SGBT), 0.73 μT/√kW (BT), and 0.56 μT/√kW (FD) and maximum SAR(10g) of 4.24 W/kg, 1.45 W/kg, and 2.04 W/kg. Dynamic pTx with 8 kT points indicate a balance between B(1)(+)(ROI) homogeneity (coefficient of variation < 14%) and efficiency (minimum B(1)(+)(ROI) > 1.11 µT/√kW) at 14.0 T with a maximum SAR(10g) < 5.25 W/kg. DISCUSSION: MRI of the human heart at 14.0 T is feasible from an electrodynamic and theoretical standpoint, provided that multi-channel high-density antennas are arranged accordingly. These findings provide a technical foundation for further explorations into CMR at 14.0 T.
Keywords:Electrodynamics, Ultrahigh Field MR, Electrical Dipole, Parallel Transmission, Cardiovascular MRI
Source:Magnetic Resonance Materials in Physics Biology and Medicine
Page Range:257-277
Date:April 2023
Official Publication:https://doi.org/10.1007/s10334-023-01075-1
PubMed:View item in PubMed

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