guest ::
| Home > Publications database > Comparison of B 1 + and SAR efficiency for a high-impedance metamaterial shield with different remote RF arrays at 7 T MRI: A simulation study. |
| Home > Publications database > Comparison of B 1 + and SAR efficiency for a high-impedance metamaterial shield with different remote RF arrays at 7 T MRI: A simulation study. |
| Journal Article | DKFZ-2025-01882 |
; ; ;
2025
Springer
Heidelberg
This record in other databases: 
Please use a persistent id in citations: doi:doi:10.1007/s10334-025-01295-7
Abstract: This study explores high-impedance surface (HIS) metamaterial shields for enhancing the transmit field in whole-body MRI at 7 T. We studied the possibility of placing a metamaterial layer between the gradient coil and bore liner using electromagnetic simulations to evaluate B1+ and SAR efficiency across different impedances.Simulations were performed in three stages, first metamaterial design and characterization, then single-element dipole simulations with a homogenous phantom, and finally, simulations including a four-element arrays with a virtual body model, including the whole scanner geometry. Four antenna types were evaluated for B1+ and SAR efficiency.Due to space constraints the metamaterial does not reach high enough impedance, resulting in minimal performance gains for most antennas. However, fractionated dipole arrays with inductances showed increased SAR efficiency and a larger field of view. Higher impedance values (above 1000 Ω) reduced losses and enabled higher-order wave modes, improving efficiency. Intermediate impedances (10⁻2-103 Ω) introduced significant losses, potentially causing heating and detuning.HIS metamaterials can enhance transmit performance in 7 T MRI but require careful optimization of impedance, material losses, and antenna design. These factors must be considered to ensure both efficacy and safety in ultra-high-field applications.
Keyword(s): Electromagnetic simulations ; MRI ; Metamaterials ; Ultra-high field
; Clarivate Analytics Master Journal List ; Current Contents - Clinical Medicine ; DEAL Springer ; DEAL Springer ; Essential Science Indicators ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection
|
The record appears in these collections: |