volume | PIER Journals

Abstract

A magnetic resonance imaging (MRI) duodenoscope is demonstrated, by combining non-magnetic endoscope components with a thin-film receiver based on a magneto-inductive waveguide. The waveguide elements consist of figure-of-eight shaped inductors formed on either side of a flexible substrate and parallel plate capacitors that use the substrate as a dielectric. Operation is simulated using equivalent circuit models and by computation of two- and three-dimensional sensitivity patterns. Circuits are fabricated for operation at 127.7 MHz by double-sided patterning of copper-clad Kapton and assembled onto non-magnetic flexible endoscope insertion tubes. Operation is verified by bench testing and by 1H MRI at 3T using phantoms. The receiver can form a segmented coaxial image along the length of the endoscope, even when bent, and shows a signal-to-noise-ratio advantage over a surface array coil up to three times the tube diameter at the tip. Initial immersion imaging experiments have been carried out and confirm an encouraging lack of sensitivity to RF heating.

1. Hoult, D. I. and P. C. Lauterbur, "The sensitivity of the zeugmatographic experiment involving human samples," J. Magn. Reson., Vol. 34, 425-433, 1979. Google Scholar

2. Ocali, O. and E. Atalar, "Ultimate intrinsic signal-to-noise ratio in MRI," Magn. Reson. Med., Vol. 39, 462-473, 1988.
doi:10.1002/mrm.1910390317 Google Scholar

3. Eryaman, Y., Y. Oner, and E. Atalar, "Design of internal coils using ultimate intrinsic SNR," Magn. Reson. Mater. Phys., Vol. 22, 221-228, 2009.
doi:10.1007/s10334-009-0167-1 Google Scholar

4. Inui, K., S. Nakazawa, J. Yoshino, et al. "Endoscopic MRI: Preliminary results of a new technique for visualization and staging of gastrointestinal tumors," Endoscopy, Vol. 27, 480-485, 1995.
doi:10.1055/s-2007-1005752 Google Scholar

5. Gilderdale, D. J., A. D. Williams, U. Dave, and N. M. de Souza, "An inductively-coupled, detachable receiver coil system for use with magnetic resonance compatible endoscopes," JMRI, Vol. 18, 131-135, 2003.
doi:10.1002/jmri.10321 Google Scholar

6. Syms, R. R. A., I. R. Young, C. A. Wadsworth, S. D. Taylor-Robinson, and M. Rea, "Magnetic resonance imaging duodenoscope," IEEE Trans. Biomed. Engng., Vol. 60, 3458-3467, 2013.
doi:10.1109/TBME.2013.2271045 Google Scholar

7. Kantor, H. L., R. W. Briggs, and R. S. Balaban, "In vivo ³¹P nuclear magnetic resonance measurements in canine heart using a catheter-coil," Circ. Res., Vol. 55, 261-266, 1984.
doi:10.1161/01.RES.55.2.261 Google Scholar

8. Martin, P. J., D. B. Plewes, and R. M. Henkelman, "MR imaging of blood vessels with an intravascular coil," J. Magn. Reson. Imag., Vol. 2, 421-429, 1992.
doi:10.1002/jmri.1880020411 Google Scholar

9. Atalar, E., P. A. Bottomley, O. Ocali, L. C. L. Correia, M. D. Kelemen, J. A. C. Lima, and E. A. Zerhouni, "High resolution intravascular MRI and MRS by using a catheter receiver coil," Magn. Reson. Med., Vol. 36, 596-605, 1996.
doi:10.1002/mrm.1910360415 Google Scholar

10. Bottomley, P. A., E. Atalar, R. F. Lee, K. A. Shunk, and A. Lardo, "Cardiovascular MRI probes for the outside in and for the inside out," Magn. Reson. Mats. Phys. Biol. Med., Vol. 11, 49-51, 2000.
doi:10.1007/BF02678493 Google Scholar

11. Duerk, J. L., E. Y. Wong, and J. S. Lewin, "A brief review of hardware for catheter tracking in magnetic resonance imaging," MAGMA, Vol. 13, 199-208, 2002.
doi:10.1016/S1352-8661(01)00150-8 Google Scholar

12. Boskamp, E., "Improved surface coil imaging in MRI: Decoupling of the excitation and receiver coils," Radiology, Vol. 157, 449-452, 1985.
doi:10.1148/radiology.157.2.4048454 Google Scholar

13. Nitz, W. R., A. Oppelt, W. Renz, C. Manke, M. Lenhart, and J. Link, "On the heating of linear conductive structures as guidewires and catheters in interventional MRI," J. Magn. Reson. Imag., Vol. 13, 105-114, 2001.
doi:10.1002/1522-2586(200101)13:1<105::AID-JMRI1016>3.0.CO;2-0 Google Scholar

14. Atalar, E., "Safe coaxial cables," Proc. 7th Ann. Meet. ISMRM, 1006, Philadelphia, PA, USA, May 24–28, 1999. Google Scholar

15. Ladd, M. E. and H. H. Quick, "Reduction of resonant RF heating in intravascular catheters using coaxial chokes," Magn. Reson. Med., Vol. 43, 615-619, 2000.
doi:10.1002/(SICI)1522-2594(200004)43:4<615::AID-MRM19>3.0.CO;2-B Google Scholar

16. Vernickel, P., V. Schulz, S. Weiss, and B. Gleich, "A safe transmission line for MRI," IEEE Trans. Biomed. Engng., Vol. 52, 1094-1102, 2005.
doi:10.1109/TBME.2005.846713 Google Scholar

17. Krafft, A., S. Muller, R. Umathum, W. Semmler, and M. Bock, "B₁ field-insensitive transformers for RF-safe transmission lines," Magn. Reson. Mater. Phys., Vol. 19, 257-266, 2006.
doi:10.1007/s10334-006-0055-x Google Scholar

18. Wiltshire, M. C. K., J. V. Hajnal, J. B. Pendry, D. J. Edwards, and C. J. Stevens, "Metamaterial endoscope for magnetic field transfer: Near field imaging with magnetic wires," Optics Express, Vol. 11, 709-714, 2003.
doi:10.1364/OE.11.000709 Google Scholar

19. Freire, M. J. and R. Marques, "Planar magnetoinductive lens for three-dimensional subwavelength imaging," Appl. Phys. Letts., Vol. 86, art. 182505, 2005.
doi:10.1063/1.1922074 Google Scholar

20. Freire, M. J., R. Marques, and L. Jelinek, "Experimental demonstration of a μ_r = −1 metamaterial lens for magnetic resonance imaging," Appl. Phys. Lett., Vol. 93, 231108, 2008.
doi:10.1063/1.3043725 Google Scholar

21. Schelekova, A. V., A. P. Slobozhanyuk, S. B. Glybovski, et al. "Application of metasurfaces for magnetic resonance imaging," Proc. 10th Metamaterials Conf., 13-14, Platanias, Crete, Sept. 17– 22, 2016. Google Scholar

22. Slobozhanyuk, A. P., A. N. Poddubny, A. J. E. Raaijmakers, et al. "Enhancement of magnetic resonance imaging with metasurfaces," Adv. Mats., Vol. 28, 1832-1838, 2016.
doi:10.1002/adma.201504270 Google Scholar

23. Belov, P. A. and Y. Hao, "Subwavelength imaging at optical frequencies using a transmission device formed by a periodic metal-dielectric structure operating in the canalization regime," Phys. Rev. B, Vol. 73, 113110, 2006.
doi:10.1103/PhysRevB.73.113110 Google Scholar

24. Radu, X., D. Garray, and C. Craeye, "Towards a wire medium endoscope for MRI imaging," Metamaterials, Vol. 3, 90-99, 2009.
doi:10.1016/j.metmat.2009.07.005 Google Scholar

25. Belov, P. A., G. K. Palikaras, Y. Zhao, et al. "Experimental demonstration of multiwire endoscopes capable of manipulating near-fields with sub-wavelength resolution," Appl. Phys. Lett., Vol. 97, 191905, 2010.
doi:10.1063/1.3516161 Google Scholar

26. Syms, R. R. A., I. R. Young, M. M. Ahmad, and M. Rea, "Magnetic resonance imaging with linear magneto-inductive waveguides," J. Appl. Phys., Vol. 112, 114911, 2012.
doi:10.1063/1.4768281 Google Scholar

27. Syms, R. R. A., I. R. Young, M. M. Ahmad, S. D. Taylor-Robinson, and M. Rea, "Magnetoinductive catheter receiver for magnetic resonance imaging," IEEE Trans. Biomed. Engng., Vol. 60, 2421-2431, 2013.
doi:10.1109/TBME.2013.2258020 Google Scholar

28. Segkhoonthod, K., R. R. A. Syms, and I. R. Young, "Design of magneto-inductive magnetic resonance imaging catheters," IEEE Sensors J., Vol. 14, 1505-1513, 2014.
doi:10.1109/JSEN.2013.2296852 Google Scholar

29. Kardoulaki, E., R. R. A. Syms, I. R. Young, and M. Rea, "SNR in MI catheter receivers for MRI," IEEE Sensors J., Vol. 16, 1700-1707, 2016.
doi:10.1109/JSEN.2015.2500226 Google Scholar

30. Syms, R. R. A., I. R. Young, L. Solymar, and T. Floume, "Thin-film magneto-inductive cables," J. Phys. D. Appl. Phys., Vol. 43, 055102, 2010.
doi:10.1088/0022-3727/43/5/055102 Google Scholar

31. Syms, R. R. A., L. Solymar, and I. R. Young, "Broad-band coupling transducers for magnetoinductive cable," J. Phys. D. Appl. Phys., Vol. 43, 285003, 2010.
doi:10.1088/0022-3727/43/28/285003 Google Scholar

32. Shamonina, E., V. A. Kalinin, K. H. Ringhofer, and L. Solymar, "Magneto-inductive waveguide," Elect. Lett., Vol. 38, 371-373, 2002.
doi:10.1049/el:20020258 Google Scholar

33. Wiltshire, M. C. K., E. Shamonina, I. R. Young, and L. Solymar, "Dispersion characteristics of magneto-inductive waves: Comparison between theory and experiment," Elect. Lett., Vol. 39, 215-217, 2003.
doi:10.1049/el:20030138 Google Scholar

34. Hoult, D. I. and R. E. Richards, "The signal-to-noise ratio of the nuclear magnetic resonance experiment," J. Magn. Reson., Vol. 24, 71-85, 1976. Google Scholar

Dr. Richard R. A. Syms

Dr. Evdokia Kardoulaki

Dr. Marc Rea

Dr. Kaushal Choonee

Dr. Simon Taylor-Robinson

Dr. Christopher Wadsworth

Dr. Ian R. Young