In this paper, we propose a cylindrical rolled-up negative permeability metamaterial (MM) lens for magnetic resonance imaging (MRI), and some analyses are given. The proposed cylindrical MM lens is fabricated by rolling a MM slab (constituted with capacitive-loaded copper split rings) into a tube that resembles a hollow ring. It can focus the field of a magnetic line source, which can increase the penetration depth and improve the sensitivity of a surface coil. The proposed cylindrical MM lens can also improve the discrimination of the signals coming from two independent sources. A clinical experiment is carried out in a General Electric Signa 1.5 T MRI system in order to verify the focusing ability of the proposed device.
2. Hornak, J. P., "The Basics of MRI,", URL, http://www.cis.rit.edu/htbooks/mri/index.html, 1996.
3. Freire, M. J., L. Jelinek, R. Marques, and M. Lapine, "On the applications of μ= -1 metamaterial lenses for magnetic resonance imaging," Journal of Magnetic Resonance, Vol. 203, 81, 2010.
doi:10.1016/j.jmr.2009.12.005
4. Freire, M. J., R. Marques, and L. Jelinek, "Experimental demonstration of a μ= -1 metamaterial lens for magnetic resonance imaging," Applied Physics Letter, Vol. 93, 231108, 2008.
doi:10.1063/1.3043725
6. Wiltshire, M. C. K., J. B. Pendry, I. R. Young, D. J. Larkman, D. J. Gilderdale, and J. V. Hajnal, "Microstructured magnetic materials for RF flux guides in magnetic resonance imaging," Science, Vol. 291, No. 5505, 2001.
doi:10.1126/science.291.5505.849
7. Radu, X., D. Garray, and C. Craeye, "Toward a wire medium endoscope for MRI imaging," Metamaterials, Vol. 3, No. 2, 90-99, 2009.
doi:10.1016/j.metmat.2009.07.005
8. Wiggins, G. C., J. R. Polimeni, A. Potthast, M. Schmitt, V. Alagappan, and L. L. Wald, "96-channel receive-only head coil for 3 Tesla: design optimization and evaluation," Magnetic Resonance in Medicine, Vol. 62, No. 3, 754-762, 2009.
doi:10.1002/mrm.22028
9. Fear, E. C., X. Li, S. C. Hagness, and M. A. Stuchly, "Confocal microwave imaging for breast cancer detection: Localization of tumors in three dimensions," IEEE Transactions on Biomedical Engineering, Vol. 49, No. 8, 2002.
doi:10.1109/TBME.2002.800759
10. Mohsin, S. A., N. M. Sheikh, and U. Saeed, "MRI induced heating of deep brain stimulation leads: Effect of the air-tissue interface," Progress In Electromagnetics Research, Vol. 83, 81-91, 2008.
doi:10.2528/PIER08040504
11. Insko, E. K., M. A. Elliott, J. C. Schotland, and J. S. Leigh, "Generalized reciprocity," Journal of Magnetic Resonance, Vol. 131, No. 111, 1998.
12. Baena, J. D., L. Jelinek, R. Marques, and M. Silveirinha, "Unified homogenization theory for magnetoinductive and electromagnetic waves in split-ring metamaterials," Physical Review A, Vol. 78, 013842, 2008.
doi:10.1103/PhysRevA.78.013842
13. Rennings, A., P. Schneider, S. Otto, D. Erni, C. Caloz, and M. E. Ladd, "A CRLH zeroth-order resonant antenna (ZORA) with high near-¯eld polarization purity used as an RF coil element for ultra high field MRI," Metamaterials, 13-16, 2010.
14. Gong, Y. and G. Wang, "Superficial tumor hyperthermia with flat left-handed metamaterial lens," Progress In Electromagnetics Research, Vol. 98, 389-405, 2009.
doi:10.2528/PIER09091401
15. Lapine, M., L. Jelinek, M. J. Freire, and R. Marques, "Realistic metamaterial lenses: Limitations imposed by discrete structure," Physical Review B, Vol. 82, 165124, 2010.
doi:10.1103/PhysRevB.82.165124
16. Sydoruk, O., E. Tatartschuk, E. Shamonina, and L. Solymar, "Resonant frequency of singly split single ring resonators: An analytical and numerical study," Metamaterials, 632-634, 2008.
17. Algarin, J. M., M. J. Freire, M. A. Lopez, M. Lapine, P. M. Jakob, V. C. Behr, and R. Marques, "Analysis of the resolution of split-ring metamaterial lenses with application in parallel magnetic resonance imaging," Applied Physics Letter, Vol. 98, 014105, 2011.
doi:10.1063/1.3533394
18. Joines, W. T., Y. Zhang, C. Li, and R. L. Jirtle, "The measured electrical properties of normal and malignant human tissues from 50 to 900 MHz," Medical Physics, Vol. 21, 547, 1994.