volume | PIER Journals

Abstract

Medical implants in the form of linear conductive structures partially insulated along their length are especially prone to induced heating when subjected to the radiofrequency field used during magnetic resonance imaging (MRI). Leads or similar structures are often implanted near the skin and we have analyzed such implants when the implantation depth is varied in steps from 3 mm to 9 mm or more. Current, electric field, and induced temperature rise distributions in tissue have been obtained. The results have been validated by laboratory measurements.

1. Nyenhuis, J. A., S. M. Park, R. Kamondetdacha, A. Amjad, F. G. Shellock, and A. Rezai, "MRI and implanted medical devices: Basic interactions with an emphasis on heating," IEEE Trans. Device and Materials Reliability, Vol. 5, No. 3, Sep. 2005. Google Scholar

2. Park, S. M., R. Kamondetdacha, A. Amjad, and J. A. Nyenhuis, "MRI safety: RF induced heating on straight wires," IEEE Trans. Magn., Vol. 41, No. 10, 4197-4199, Oct. 2005.
doi:10.1109/TMAG.2005.854803 Google Scholar

3. Ho, H. S., "Safety of metallic implants in magnetic resonance imaging," J. Magn. Reson. Imag., Vol. 14, 472-474, 2001.
doi:10.1002/jmri.1209 Google Scholar

4. Amjad, A., Specific absorption rate during magnetic resonance imaging, Ph.D Thesis, Purdue University, 2007.

5. Mohsin, S. A., N. M. Sheikh, and U. Saeed, "MRI-induced heating of deep brain stimulation leads," Phys. Med. Biol., 5745-5756, 2008.
doi:10.1088/0031-9155/53/20/012 Google Scholar

6. Jin, J. M., J. Chen, W. C. Chew, H. Gan, R. L. Magin, and P. J. Dimbylow, "Computation of electromagnetic fields for high-frequency magnetic resonance imaging applications ," Phys. Med. Biol., Vol. 41, 2719-2738, 1996.
doi:10.1088/0031-9155/41/12/011 Google Scholar

7. Kainz, W., SAR intercomparison protocol for 1.5T MR systems draft, U.S. Food and Drug Administration, Center for Devices and Radiological Health, Office of Science and Engineering Laboratories, 2006.

8. Park, S.-M., R. Kamondetdacha, and J. A. Nyenhuis, "Calculation of MRI-induced heating of an implanted medical lead wire with an electric field transfer function," J. Magn. Reson. Imag., Vol. 26, 1278-1285, 2007.
doi:10.1002/jmri.21159 Google Scholar

9. Volakis, J. L., A. Chatterjee, and L. C. Kempel, "Review of the finite-element method for three-dimensional electromagnetic scattering," J. Opt. Soc. Am. A, Vol. 11, No. 4, Apr. 1994.
doi:10.1364/JOSAA.11.001422 Google Scholar

10. Jin, J., The Finite Element Method in Electromagnetics, 2nd Ed., Chaps. 5, 8, and 9, John Wiley and Sons, 2002.

11. 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 Google Scholar

Professor Syed Mohsin

Dr. John Nyenhuis

Dr. Rizwan Masood