Radiofrequency antenna concepts for human cardiac MR at 14.0 T.

Autor: Nurzed B; Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin Ultrahigh Field Facility (B.U.F.F.), Robert Rössle Strasse 10, 13125, Berlin, Germany., Kuehne A; MRI.TOOLS GmbH, Berlin, Germany., Aigner CS; Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Berlin, Germany., Schmitter S; Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Berlin, Germany., Niendorf T; Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin Ultrahigh Field Facility (B.U.F.F.), Robert Rössle Strasse 10, 13125, Berlin, Germany. thoralf.niendorf@mdc-berlin.de.; MRI.TOOLS GmbH, Berlin, Germany. thoralf.niendorf@mdc-berlin.de.; Experimental and Clinical Research Center (ECRC), a joint cooperation between the Charité Medical Faculty and the Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany. thoralf.niendorf@mdc-berlin.de., Eigentler TW; Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin Ultrahigh Field Facility (B.U.F.F.), Robert Rössle Strasse 10, 13125, Berlin, Germany.; Chair of Medical Engineering, Technische Universität Berlin, Berlin, Germany.
Jazyk: angličtina
Zdroj: Magma (New York, N.Y.) [MAGMA] 2023 Apr; Vol. 36 (2), pp. 257-277. Date of Electronic Publication: 2023 Mar 15.
DOI: 10.1007/s10334-023-01075-1
Abstrakt: 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.
(© 2023. The Author(s).)
Databáze: MEDLINE
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