volume | PIER Journals

Abstract

We report decoupling of two closely located resonant dipole antennas dedicated for ultra-high field magnetic resonance imaging (MRI). We show that a scatterer slightly raised over the plane of antennas grants a sufficient decoupling even for antennas separated by very small gap (below 1/30 of the wavelength). We compare the operations of two decoupling scatterers. One of them is a shortcut resonant dipole, and the other is a split-loop resonator (SLR). Previously, we have shown that the SLR offers a wider operational band than the dipole and the same level of decoupling. However, it was so for an array in free space. The presence of the body phantom drastically changes the decoupling conditions. Moreover, the requirement to minimize the parasitic scattering from the decoupling element into the body makes the decoupling dipole much more advantageous than the SLR.

1. Juntu, J., J. Sijbers, D. Van Dyck, and J. Gielen, "Bias field correction for MRI images," Comp. Recog. Sys., Vol. 32, 543-551, 2005.

2. Baselice, F., G. Ferraioli, and A. Shabou, "Field map reconstruction in magnetic resonance imaging using Bayesian estimation," Sensors, Vol. 10, No. 1, 266-279, 2010.
doi:10.3390/s100100266

3. Olafsson, V. T., D. C. Noll, and J. A. Fessler, "Fast joint reconstruction of dynamic R2 and field maps in functional MRI," IEEE Trans. Med. Imag., Vol. 27, No. 9, 1177-1188, 2008.
doi:10.1109/TMI.2008.917247

4. Mao, W., M. B. Smith, and C. M. Collins, "Exploring the limits of RF shimming for high-field MRI of the human head," Magn. Reson. Med., Vol. 56, No. 4, 918-922, 2006.
doi:10.1002/mrm.21013

5. Ibrahim, T. S. and L. Tang, "Insight into RF power requirements and B1 field homogeneity for human MRI via rigorous FDTD approach," J. Magn. Reson. Imaging, Vol. 25, No. 6, 1235-1247, 2007.
doi:10.1002/jmri.20919

6. Avdievich, N. I., J. W. Pan, and H. P. Hetherington, "Resonant inductive decoupling (RID) for transceiver arrays to compensate for both reactive and resistive components of the mutual impedance," NMR Biomed., Vol. 26, No. 11, 1547-1554, 2013.
doi:10.1002/nbm.2989

7. Von Morze, C., J. Tropp, S. Banerjee, D. Xu, K. Karpodinis, L. Carvajal, C. P. Hess, P. Mukherjee, S. Majumdar, and D. B. Vigner, "An eight-channel, nonoverlapping phased array coil with capacitive decoupling for parallel MRI at 3 T," Concepts in Magnetic Resonance B: Magnetic Resonance Engineering, Vol. 31, 37-43, 2007.
doi:10.1002/cmr.b.20078

8. Van de Moortele, P. F., T. Vaughan, and K. A. Ugurbil, "A 32-channel lattice transmission line array for parallel transmit and receive MRI at 7 Tesla," Magn. Reson. Med., Vol. 63, No. 6, 1478-1485, 2010.
doi:10.1002/mrm.22413

9. Adriany, G., P. F. Van de Moortele, F. Wiesinger, S. Moeller, J. P. Strupp, P. Andersen, C. Snyder, X. Zhang, X. Chen, K. P. Pruessmann, P. Boesiger, J. T. Vaughan, and K. Ugurbil, "Transmit and receive transmission line arrays for 7 Tesla parallel imaging," Magn. Reson. Med., Vol. 53, 434-445, 2005.
doi:10.1002/mrm.20321

10. Padormo, F., A. Beqiri, J. V. Hajnal, and S. J. Malik, "Parallel transmission for ultrahigh-field imaging," NMR Biomed., Vol. 29, No. 9, 1145-1161, 2015.
doi:10.1002/nbm.3313

11. Filonov, D. S., A. S. Shalin, I. Irosh, P. A. Belov, and P. Ginzburg, "Controlling electromagnetic scattering with wire metamaterial resonators," J. Opt. Soc. Am. A, Vol. 33, No. 10, 1910-1916, 2016.
doi:10.1364/JOSAA.33.001910

12. Hurshkainen, A. A., T. A. Derzhavskaya, S. G. Glybovski, I. J. Voogt, I. V. Melchakova, C. A. T. Van den Berg, and A. J. E. Raaijmakers, "Element decoupling of 7 T dipole body arrays by EBG metasurface structures: Experimental verification," J. Mag. Reson., Vol. 269, 87-96, 2016.
doi:10.1016/j.jmr.2016.05.017

13. Fenn, A. J., Adaptive Antennas and Phased Arrays for Radar and Communications, Artech House, 2008.

14. Lau, B. K. and J. B. Andersen, "Simple and efficient decoupling of compact arrays with parasitic scatterers," IEEE Trans. Antennas Propag., Vol. 60, No. 11, 464-472, 2012.
doi:10.1109/TAP.2011.2173440

15. Mollaei, M. S. M., A. Hurshkainen, S. Kurdjumov, S. Glybovski, and C. Simovski, "Passive electromagnetic decoupling in an active metasurface of dipoles," Phot. Nanost. Fund. Appl., DOI.org/10.1016/j.photonics.2018.10.001.

16. Mollaei, M. S. M., A. Hurshkainen, S. Glybovski, and C. Simovski, "Decoupling of two closely located dipole antennas by a split-loop resonator," Radio Sci., Vol. 53, No. 11, 1398-1405, 2018.
doi:10.1029/2018RS006679

17. Krasnok, A. E., A. P. Slobozhanyuk, C. R. Simovski, S. A. Tretyakov, A. N. Poddubny, A. E. Miroshnichenko, Y. S. Kivshar, and P. A. Belov, "An antenna model for the Purcell effect," Scientific Reports, Vol. 5, 1-12, 2015.

18. Pethig, R., "Dielectric properties of body tissues," Clin. Phys. Physiol. Meas., Vol. 8, 5-12, 1987.
doi:10.1088/0143-0815/8/4A/002

19. Halter, R. J., A. Schned, J. Heaney, A. Hartov, and K. D. Paulsen, "Electrical properties of prostatic tissues: I. Single frequency admittivity properties," J. Urol., Vol. 182, No. 4, 1600-1607, 2009.
doi:10.1016/j.juro.2009.06.007

20. Giovanetti, G., F. Frija, L. Menichetti, V. Hartwig, V. Viti, and L. Landini, "An efficient method for electrical conductivity measurement in the RF range," Concepts in Magnetic Resonance Research B, Vol. 37B, 160-165, 2010.
doi:10.1002/cmr.b.20165

Dr. Masoud Sharifian Mazraeh Mollaei

Dr. Sergei Alexandrovich Kurdjumov

Dr. Anna Hurshkainen

Dr. Constantin Rufovich Simovski