title: Effect of the extracranial deep brain stimulation lead on radiofrequency heating at 9.4 Tesla (400.2 MHz).
abstract: OBJECTIVE
  To study the effect of the extracranial portion of a deep brain stimulation (DBS) lead on radiofrequency (RF) heating with a transmit and receive 9.4 Tesla head coil.
  
  
  METHODS
  The RF heating was studied in four excised porcine heads (mean animal head weight = 5.46 +/- 0.14 kg) for each of the following two extracranial DBS lead orientations: one, parallel to the coil axial direction; two, perpendicular to the coil axial direction (i.e., azimuthal). Temperatures were measured using fluoroptic probes at four locations: one, scalp; two, near the second DBS lead electrode-brain contact; three, near the distal tip of the DBS lead; and four, air surrounding the head. A continuous wave RF power was delivered to each head for 15 min using the coil. Net, delivered RF power was measured at the coil (mean whole head average specific absorption rate = 2.94 +/- 0.08 W/kg).
  
  
  RESULTS
  RF heating was significantly reduced when the extracranial DBS lead was placed in the axial direction (temperature change = 0-5 degrees C) compared with the azimuthal direction (temperature change = 1-27 degrees C).
  
  
  CONCLUSIONS
  Development of protocols seems feasible to keep RF heating near DBS electrodes clinically safe during ultra-high field head imaging.
authors.affiliation: Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota 55455, USA. dev@cmrr.umn.edu
authors.forename: Devashish
authors.initials: D
authors.lastname: Shrivastava
authors.forename: Aviva
authors.initials: A
authors.lastname: Abosch
authors.forename: Timothy
authors.initials: T
authors.lastname: Hanson
authors.forename: Jinfeng
authors.initials: J
authors.lastname: Tian
authors.forename: Akshay
authors.initials: A
authors.lastname: Gupte
authors.forename: Paul A
authors.initials: PA
authors.lastname: Iaizzo
authors.forename: J Thomas
authors.initials: JT
authors.lastname: Vaughan
mesh_terms: D000818:Animals; D016477:Artifacts; D001921:Brain / Q000503:physiopathology / Q000528:radiation effects*; D046690:Deep Brain Stimulation / Q000009:adverse effects* / Q000379:methods*; D004195:Disease Models, Animal; D004567:Electrodes, Implanted; D006358:Hot Temperature / Q000009:adverse effects*; D066298:In Vitro Techniques; D008279:Magnetic Resonance Imaging / Q000379:methods*; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D013552:Swine; D013817:Thermography
references.citation: Int J Hyperthermia. 2003 May-Jun;19(3):267-94
references.pmid: 12745972
references.citation: J Magn Reson Imaging. 2002 Mar;15(3):241-50
references.pmid: 11891968
references.citation: Magn Reson Med. 2009 Jun;61(6):1500-6
references.pmid: 19319895
references.citation: Magn Reson Imaging. 2005 May;23(4):549-55
references.pmid: 15919600
references.citation: Biomed Eng Online. 2002 Sep 12;1:2
references.pmid: 12437766
references.citation: Magn Reson Med. 1991 Dec;22(2):467-80
references.pmid: 1812380
references.citation: Magn Reson Med. 2009 Oct;62(4):888-95
references.pmid: 19572392
references.citation: Neuroimage. 2007 Aug 15;37(2):508-17
references.pmid: 17590355
references.citation: J Magn Reson Imaging. 2006 Dec;24(6):1236-42
references.pmid: 17078088
references.citation: Physiol Rev. 1981 Apr;61(2):435-514
references.pmid: 7012860
references.citation: Phys Med Biol. 1996 Nov;41(11):2231-49
references.pmid: 8938024
references.citation: J Magn Reson Imaging. 2009 Feb;29(2):461-5
references.pmid: 19161203
references.citation: J Magn Reson Imaging. 2004 Aug;20(2):315-20
references.pmid: 15269959
references.citation: Magn Reson Med. 2004 Oct;52(4):851-9
references.pmid: 15389967
references.citation: Neurosci Behav Physiol. 2005 Jul;35(6):615-21
references.pmid: 16342618
references.citation: J Magn Reson. 1998 Nov;135(1):260-4
references.pmid: 9799704
references.citation: Arctic Med Res. 1989 Apr;48(2):75-86
references.pmid: 2736003
references.citation: Magn Reson Med. 2002 Apr;47(4):629-33
references.pmid: 11948722
references.citation: Magn Reson Med. 2002 May;47(5):982-9
references.pmid: 11979578
references.citation: J Biomech Eng. 2009 Jul;131(7):074506
references.pmid: 19640142
references.citation: MAGMA. 2008 Mar;21(1-2):95-101
references.pmid: 18210177
references.citation: Neurosurgery. 2005 Oct;57(4 Suppl):392-7; discussion 392-7
references.pmid: 16234691
references.citation: Magn Reson Med. 2004 Feb;51(2):380-8
references.pmid: 14755664
references.citation: J Neurophysiol. 2005 Nov;94(5):3069-80
references.pmid: 16014800
references.citation: Magn Reson Med. 2009 Oct;62(4):1073-9
references.pmid: 19645006
references.citation: AJNR Am J Neuroradiol. 2002 Nov-Dec;23(10):1795-802
references.pmid: 12427641
references.citation: Magn Reson Med. 2001 Jul;46(1):24-30
references.pmid: 11443707
references.citation: Magn Reson Med. 2008 Jan;59(1):73-8
references.pmid: 17969077
references.citation: Magn Reson Med. 2006 Dec;56(6):1274-82
references.pmid: 17075852
references.citation: Tohoku J Exp Med. 1982 Jan;136(1):79-87
references.pmid: 7071832
references.citation: Magn Reson Med. 2009 Jun;61(6):1279-85
references.pmid: 19319893
references.citation: Magn Reson Med. 2005 Dec;54(6):1503-18
references.pmid: 16270333
references.citation: Health Phys. 2004 Aug;87(2):197-216
references.pmid: 15257220