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Heating and Safety Concerns of the Radio-Frequency Field in MRI

  • MRI Safety (M Bock, Section Editor)
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Abstract

Magnetic resonance imaging (MRI) is a widely used and powerful imaging technique for non-invasive clinical diagnosis. The absorbed radiofrequency (RF) energy must be carefully managed, as MRI presents one of the highest RF exposures to humans. Temperature increases in the patient caused by high-level RF exposure is a major safety concern in MRI, potentially causing local thermal tissue damage or systemic overheating. This review article summarizes recent findings in MR safety research, including the clear distinction between exposures of patients with and without implants; evaluates the advantages and limitations of numerical simulations for RF safety assessment in MRI; and discusses the need for additional research at high RF exposure levels and in novel MRI systems.

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References

Papers of particular interest, published recently, have been highlighted as: • Of importance •• Of major importance

  1. ICNIRP. Guidelines for limiting exposure to time-varying electric, magnetic, and electromagnetic fields (up to 300 GHz). Health Phys. 1998;74:494–522.

    Google Scholar 

  2. IEC. Medical electrical equipment—particular requirements for the basic safety and essential performance of magnetic resonance equipment for medical diagnosis, Edition 3.2. IEC 60601-2-33:2010 + AMD1:2013 + AMD2:2015 CSV 2015.

  3. Luechinger R. MRI safety. In: Syed MA, Mohiaddin RH, editors. Magnetic resonance imaging of congenital heart disease. New York: Springer; 2012. p. 39–46.

    Chapter  Google Scholar 

  4. Langman DA, Srinivasan S, Ennis D. What is the SAR for routine clinical MRI exams at 1.5 T? Proc Intl Soc Magn Reson Med. 2015;23:0302.

    Google Scholar 

  5. • Guérin B, Gebhardt M, Serano P, Adalsteinsson E, Hamm M, Pfeuffer J, Nistler J, Wald LL. Comparison of simulated parallel transmit body arrays at 3 T using excitation uniformity, global SAR, local SAR, and power efficiency metrics. Magn Reson Med. 2014;1150:1137–50. Application study, evaluating SAR exposures as a function of different pTx body array coils and their excitations.

  6. Brunner DO, Pruessmann KP. Optimal design of multiple-channel RF pulses under strict power and SAR constraints. Magn Reson Med. 2010;63:1280–91.

    Article  PubMed  Google Scholar 

  7. Malik SJ, Beqiri A, Padormo F, Hajnal JV. Direct signal control of the steady-state response of 3D-FSE sequences. Magn Reson Med. 2014;73:951–63.

    Article  PubMed  Google Scholar 

  8. Van Osch MJP, Webb AG. Safety of ultra-high field MRI: what are the specific risks? Curr Radiol Rep. 2014;2:61.

    Article  Google Scholar 

  9. Christ A, Kainz W, Hahn EG, et al. The virtual family—development of surface-based anatomical models of two adults and two children for dosimetric simulations. Phys Med Biol. 2010;55:N23–38.

    Article  PubMed  Google Scholar 

  10. Gosselin M-C, Neufeld E, Moser H, et al. Development of a new generation of high-resolution anatomical models for medical device evaluation: the virtual population 3.0. Phys Med Biol. 2014;59:5287–303.

    Article  PubMed  Google Scholar 

  11. Hasgall PA, Di Gennaro F, Baumgartner C, Neufeld E, Gosselin MC, Payne D, Klingenböck A, Kuster N. IT’IS database for thermal and electromagnetic parameters of biological tissues. Version 2.5. www.itis.ethz.ch/database (2014). Accessed 1 Aug 2014

  12. Laakso I, Hirata A. Dominant factors affecting temperature rise in simulations of human thermoregulation during RF exposure. Phys Med Biol. 2011;56:7449–71.

    Article  PubMed  Google Scholar 

  13. • Murbach M, Neufeld E, Capstick M, Kainz W, Brunner DO, Samaras T, Pruessmann KP, Kuster N. Thermal tissue damage model analyzed for different hole-body SAR and scan durations for standard MR body coils. Magn Reson Med. 2014;71:421–31. Concept of thermal dose (CEM43) evaluation in MRI exposures, using various anatomical human models in different imaging positions.

  14. Nadobny J, Szimtenings M, Diehl D, Stetter E, Brinker G, Wust P. Evaluation of MR-induced hot spots for different temporal SAR modes using a time-dependent temperature gradient treatment. IEEE Trans Biomed Eng. 2007;54:1837–50.

    Article  PubMed  Google Scholar 

  15. •• Neufeld E, Fuetterer M, Murbach M, Kuster N. Rapid method for thermal dose-based safety supervision during MR scans. Bioelectromagnetics. 2015;36:398–407. Methodology for the rapid assessment of thermal dose in MR-scanning, based on the actual SAR sequence of the scanner.

  16. Fujimoto M, Hirata A, Wang J, Fujiwara O, Shiozawa T. FDTD-derived correlation of maximum temperature increase and peak SAR in child and adult head models due to dipole antenna. IEEE Trans Electromagn Compat. 2006;48:240–7.

    Article  Google Scholar 

  17. Hirata A, Laakso I, Oizumi T, Hanatani R, Chan KH, Wiart J. The relationship between specific absorption rate and temperature elevation in anatomically based human body models for plane wave exposure from 30 MHz to 6 GHz. Phys Med Biol. 2013;58:903–21.

    Article  PubMed  Google Scholar 

  18. Hirata A, Shiozawa T. Correlation of maximum temperature increase and peak SAR in the human head due to handset antennas. IEEE Trans Microw Theory Tech. 2003;51:1834–41.

    Article  Google Scholar 

  19. Collins CM, Liu W, Wang J, Gruetter R, Vaughan JT, Ugurbil K, Smith MB. Temperature and SAR Calculations for a human head within volume and surface coils at 64 and 300 MHz. J Mag Res Imag. 2004;19:650–6.

    Article  Google Scholar 

  20. Wang Z, Lin JC, Mao W, Liu W, Smith MB, Collins CM. SAR and temperature: simulations and comparison to regulatory limits for MRI. J Mag Res Imag. 2007;26:437–41.

    Article  Google Scholar 

  21. Samaras T, Kalampaliki E, Sahalos JN. Influence of thermophysiological parameters on the calculations of temperature rise in the head of mobile phone users. IEEE Trans Electromagn Compat. 2007;49:936–9.

    Article  Google Scholar 

  22. IARC. IARC Monographs Vol. 102. Non-ionizing radiation. Part 2: Radiofrequency electromagnetic fields. 2013;102:460.

  23. Loughran SP, McKenzie RJ, Jackson ML, Howard ME, Croft RJ. Individual differences in the effects of mobile phone exposure on human sleep: rethinking the problem. Bioelectromagnetics. 2012;33:86–93.

    Article  PubMed  Google Scholar 

  24. Murbach M, Cabot E, Neufeld E, Gosselin M-C, Christ A, Kuster N. Local SAR enhancements in anatomically correct children and adult models as a function of position within 1.5 T MR body coil. Prog Biophys Mol Biol. 2011;107:428–33.

    Article  PubMed  Google Scholar 

  25. Abart J, Brinker G, Irlbacher W, Grebmeier J. Temperature and heart rate changes in MRI at SAR levels of up to 3 W/kg. Proc Intl Soc Magn Reson Med. 1989;998.

  26. Adair ER, Berglund LG. Predicted thermophysiological responses of humans to MRI fields. Ann N Y Acad Sci. 1992;649:188–200.

    Article  CAS  PubMed  Google Scholar 

  27. Wust P, Nadobny J, Szimtenings M, Stetter E, Gellermann J. Implications of clinical RF hyperthermia on protection limits in the RF range. Health Phys. 2007;92:565–73.

    Article  CAS  PubMed  Google Scholar 

  28. Murbach M, Neufeld E, Cabot E, Zastrow E, Juan C, Kainz W, Kuster N. Virtual Population-based assessment of the impact of 3 Tesla radiofrequency shimming and thermoregulation on safety and B1+ uniformity. Magn Reson Med. 2015. doi:10.1002/mrm.25986.

    PubMed  Google Scholar 

  29. Graven-Nielsen T, Arendt-Nielsen L, Mense S. Thermosensitivity of muscle: high-intensity thermal stimulation of muscle tissue induces muscle pain in humans. J Physiol. 2002;540:647–56.

    Article  PubMed Central  CAS  PubMed  Google Scholar 

  30. Sapareto SA, Dewey WC. Thermal dose determination in cancer therapy. Int J Radiat Oncol Biol Phys. 1984;10:787–800.

    Article  CAS  PubMed  Google Scholar 

  31. Dewhirst MW, Viglianti BL, Lora-Michiels M, Hanson M, Hoopes PJ. Basic principles of thermal dosimetry and thermal thresholds for tissue damage from hyperthermia. Int J Hyperth. 2003;19:267–94.

    Article  CAS  Google Scholar 

  32. Yarmolenko PS, Moon EJ, Landon C, Manzoor A, Hochman DW, Viglianti BL, Dewhirst MW. Thresholds for thermal damage to normal tissues: an update. Int J Hyperth. 2011;27:320–43.

    Article  Google Scholar 

  33. •• Van Rhoon GC, Samaras T, Yarmolenko PS, Dewhirst MW, Neufeld E, Kuster N. CEM43 °C thermal dose thresholds: a potential guide for magnetic resonance radiofrequency exposure levels? Eur Radiol. 2013;23:2215–27. Proposed thermal damage thresholds for MR exposures, which considers the risk/benefit considerations. Data is originating from multiple sources including experience from hyperthermia.

  34. •• Nadobny J, Klopfleisch R, Brinker G, Stoltenburg-Didinger G. Experimental investigation and histopathological identification of acute thermal damage in skeletal porcine muscle in relation to whole-body SAR, maximum temperature, and CEM43 C due to RF irradiation in an MR body coil of birdcage type at 123 MHz. Int J Hyperthermia. 2015;31:409–20. Experimental heating study in swine, demonstrating local tissue damage from exposure-levels currently allowed by the safety standard.

  35. Hand JW, Li Y, Hajnal JV. Numerical study of RF exposure and the resulting temperature rise in the foetus during a magnetic resonance procedure. Phys Med Biol. 2010;55:913–30.

    Article  CAS  PubMed  Google Scholar 

  36. Hand JW, Li Y, Thomas EL, Rutherford MA. Prediction of specific absorption rate in mother and fetus associated with MRI examinations during pregnancy. Magn Reson Med. 2006;55:883–93.

    Article  CAS  PubMed  Google Scholar 

  37. Hand JW, Lagendijk JJW, Hajnal JV, Lau RW, Young IR. SAR and temperature changes in the leg due to an RF decoupling coil at frequencies between 64 and 213 MHz. J Magn Reson Imaging. 2000;12:68–74.

    Article  CAS  PubMed  Google Scholar 

  38. Beqiri A, Hand JW, Hajnal JV, Malik SJ. Comparison between simulated decoupling regimes for specific absorption rate prediction in parallel transmit MRI. Magn Reson Med. 2015;74:1423–34.

    Article  PubMed  Google Scholar 

  39. Carluccio G, Collins CM, Erricolo D. A fast, analytically based method to optimize local transmit efficiency for a transmit array. Magn Reson Med. 2014;71:432–9.

    Article  PubMed Central  PubMed  Google Scholar 

  40. Eryaman Y, Guerin B, Keil B, et al. SAR reduction in 7 T C-spine imaging using a “dark modes” transmit array strategy. Magn Reson Med. 2015;73:1533–9.

    Article  PubMed  Google Scholar 

  41. Guérin B, Setsompop K, Ye H, Poser BA, Stenger AV. Design of parallel transmission pulses for simultaneous multislice with explicit control for peak power and local specific absorption rat. Magn Reson Med. 2014;73:1946–53.

    Article  PubMed  Google Scholar 

  42. Gabriel S, Lau R, Gabriel C. The dielectric properties of biological tissues: II. measurements in the frequency range 10 Hz to 20 GHz. Phys Med Biol. 1996;41:2251–69.

    Article  CAS  PubMed  Google Scholar 

  43. Mathewson KW, Haykowsky MJ, Thompson RB. Feasibility and reproducibility of measurement of whole muscle blood flow, oxygen extraction, and VO2 with dynamic exercise using MRI. Magn Reson Med. 2015. doi:10.1002/mrm.25564.

    Google Scholar 

  44. Shao Y, Zeng P, Wang S. Statistical simulation of SAR variability with geometric and tissue property changes by using the unscented transform. Magn Reson Med. 2014;2362:2357–62.

    Google Scholar 

  45. Lüdemann L, Wlodarczyk W, Nadobny J, Weihrauch M, Gellermann J, Wust P. Non-invasive magnetic resonance thermography during regional hyperthermia. Int J Hyperth. 2010;26:273–82.

    Article  Google Scholar 

  46. Gaur P, Grissom WA. Accelerated MRI thermometry by direct estimation of temperature from undersampled k-space data. Magn Reson Med. 2014;1925:1914–25.

    Google Scholar 

  47. Oh S, Ryu YC, Carluccio G, Sica CT, Collins CM. Measurement of SAR-induced temperature increase in a phantom and in vivo with comparison to numerical simulation. Magn Reson Med. 2013;1931:1923–31.

    Google Scholar 

  48. Cao Z, Oh S, Otazo R, Sica CT, Griswold MA, Collins CM. Complex difference constrained compressed sensing reconstruction for accelerated PRF thermometry with application to MRI-induced RF heating. Magn Reson Med. 2015;73:1420–31.

    Article  PubMed  Google Scholar 

  49. Shrivastava D, Utecht L, Tian J, Hughes J, Vaughan JT. In vivo radiofrequency heating in swine in a 3 T (123.2-MHz) birdcage whole body coil. Magn Reson Med. 2013;1150:1141–50.

    Google Scholar 

  50. Rieke V, Pauly KB. MR thermometry. J Magn Reson Imaging. 2008;27:376–90.

    Article  PubMed Central  PubMed  Google Scholar 

  51. Murbach M, Neufeld E, Kainz W, Pruessmann KP, Kuster N. Whole-body and local RF absorption in human models as a function of anatomy and position within 1.5 T MR body coil. Magn Reson Med. 2014;71:839–45.

    Article  PubMed  Google Scholar 

  52. Homann H, Börnert P, Eggers H, Nehrke K, Dössel O, Graesslin I. Toward individualized SAR models and in vivo validation. Magn Reson Med. 2011;66:1767–76.

    Article  CAS  PubMed  Google Scholar 

  53. Voigt T, Homann H, Katscher U, Doessel O. Patient-individual local SAR determination: in vivo measurements and numerical validation. Magn Reson Med. 2012;68:1117–26.

    Article  CAS  PubMed  Google Scholar 

  54. Winkler SA, Picot P, Thronton M, Rutt BK. Direct SAR mapping by thermoacoustic imaging: experimental proof-of-concept. Proc Intl Soc Magn Reson Med. 2015;23:3234.

    Google Scholar 

  55. Cabot E, Lloyd T, Christ A, Kainz W, Douglas M, Stenzel G, Wedan S, Kuster N. Evaluation of the RF heating of a generic deep brain stimulator exposed in 1.5 T magnetic resonance scanners. Bioelectromagnetics. 2013;34:104–13.

    Article  PubMed  Google Scholar 

  56. Luechinger R, Zeijlemaker VA, Pedersen EM, Mortensen P, Falk E, Duru F, Candinas R, Boesiger P. In vivo heating of pacemaker leads during magnetic resonance imaging. Eur Heart J. 2005;26:376–83.

    Article  PubMed  Google Scholar 

  57. Mattei E, Calcagnini G, Censi F, Triventi M, Bartolini P. Radiofrequency dosimetry in subjects implanted with metallic straight wires: a numerical study. Conf Proc Int Conf IEEE Eng Med Biol Soc. 2008;2008:4387–90.

    CAS  Google Scholar 

  58. Henderson JM, Tkach J, Phillips M, Baker K, Shellock FG, Rezai AR. Permanent neurological deficit related to magnetic resonance imaging in a patient with implanted deep brain stimulation electrodes for Parkinson’s disease: case report. Neurosurgery. 2005;57:E1063, discussion E1063.

  59. Spiegel J, Fuss G, Backens M, Reith W, Magnus T, Becker G, Moringlane J-R, Dillmann U. Transient dystonia following magnetic resonance imaging in a patient with deep brain stimulation electrodes for the treatment of Parkinson disease. Case report. J Neurosurg. 2003;99:772–4.

    Article  PubMed  Google Scholar 

  60. Acikel V, Atalar E. Modeling of radio-frequency induced currents on lead wires during MR imaging using a modified transmission line method. Med Phys. 2011;38:6623.

    Article  PubMed  Google Scholar 

  61. Baker KB, Tkach JA, Phillips MD, Rezai AR. Variability in RF-induced heating of a deep brain stimulation implant across MR systems. J Magn Reson Imaging. 2006;24:1236–42.

    Article  PubMed  Google Scholar 

  62. Nordbeck P, Weiss I, Ehses P, et al. Measuring RF-induced currents inside implants: impact of device configuration on MRI safety of cardiac pacemaker leads. Magn Reson Med. 2009;61:570–8.

    Article  PubMed  Google Scholar 

  63. Bottomley PA, Kumar A, Edelstein WA, Allen JM, Karmarkar PV. Designing passive MRI-safe implantable conducting leads with electrodes. Med Phys. 2010;37:3828–43.

    Article  PubMed  Google Scholar 

  64. •• Corcoles J, Zastrow E, Kuster N. Convex optimization of MRI exposure for mitigation of RF-heating from active medical implants. Phys Med Biol. 2015;60:7293–308. Introduction of a technique for heating mitigation through a careful design of RF exposure during MRI, considering the clinical routing of the implant.

  65. Wilkoff BL, Albert T, Lazebnik M, et al. Safe magnetic resonance imaging scanning of patients with cardiac rhythm devices: a role for computer modeling. Heart Rhythm. 2013;10:1815–21.

    Article  PubMed  Google Scholar 

  66. Gold MR, Sommer T, Schwitter J, et al. Full-body MRI scanning in patients with an ICD: primary results of the randomized Evera MRI study. J Am Coll Cardiol. 2015;65:2589–90.

    Article  Google Scholar 

  67. Gimbel JR, Bello D, Schmitt M, et al. Randomized trial of pacemaker and lead system for safe scanning at 1.5 Tesla. Heart Rhythm. 2013. doi:10.1016/j.hrthm.2013.01.022.

    Google Scholar 

  68. ISO/TS. 10974:2012, Requirements for the safety of magnetic resonance imaging for patients with an active implantable medical device. ISO/TS 10974 2012.

  69. Gupte AA, Shrivastava D, Spaniol MA, Abosch A. MRI-related heating near deep brain stimulation electrodes: more data are needed. Stereotact Funct Neurosurg. 2011;89(3):131–40.

    Article  PubMed Central  PubMed  Google Scholar 

  70. Gorny KR, Presti MF, Goerss SJ, et al. Measurements of RF heating during 3.0-T MRI of a pig implanted with deep brain stimulator. Magn Reson Imaging. 2013;31:783–88.

    Article  PubMed Central  PubMed  Google Scholar 

  71. ASTM. F2182-11a. Standard test method for measurement of radio frequency induced heating near passive implants during magnetic resonance imaging. 2011:1–8.

  72. Shellock FG, Shellock VJ. Metallic stents: evaluation of MR imaging safety. Am J Roentgenol. 1999;173(3):543–7.

    Article  CAS  Google Scholar 

  73. Camps-Raga B, Goertz W, Schaefers G, Mezape Y, Shalev A. A comparative study of numerical and experimental evaluation of RF-induced heating for an endovascular stent-graft at 1.5 T and 3 T. Biomed Eng. 2012;57:4348.

    Article  Google Scholar 

  74. Titterington B, Puschmann C, Shellock FG. A new vascular coupling device: assessment of MRI issues at 3-tesla. Magn Reson Imaging. 2014;32(5):585–9.

    Article  PubMed  Google Scholar 

  75. Kumar R, Lerski RA, Gandy S, Clift BA, Abboud RJ. Safety of orthopedic implants in magnetic resonance imaging: an experimental verification. J Orthop Res. 2006;24(9):1799–802.

    Article  PubMed  Google Scholar 

  76. Zou Y, Chu B, Wang C, Hu Z. Evaluation of MR issues for the latest standard brands of orthopedic metal implants: plates and screws. Eur J Radiol. 2015;84(3):450–7.

    Article  PubMed  Google Scholar 

  77. Liu Y, Chen J, Shellock FG, Kainz W. Computational and experimental studies of an orthopedic implant: MRI-related heating at 1.5-T/64-MHz and 3-T/128-MHz. J Mag Res Imag. 2013;37:491–7.

    Article  Google Scholar 

  78. Hasegawa M, Miyata K, Abe Y, Ishigami T. Radiofrequency heating of metallic dental devices during 3.0 T MRI. Dentomaxillofacial Radiol. 2013;42(5):1–6.

    Article  Google Scholar 

  79. Gill A, Shellock FG. Assessment of MRI issues at 3-Tesla for metallic surgical implants: findings applied to 61 additional skin closure staples and vessel ligation clips. J Cardiovasc Magn Reson. 2012;14:3.

    Article  PubMed Central  PubMed  Google Scholar 

  80. ASTM. F2503-11. Standard practice for marking medical devices and other items for safety in the magnetic resonance environment. 2013:1–7.

  81. Shellock FG, Woods TO, Crues JV. MR labeling information for implants and devices: explanation of terminology. Radiology. 2009;253(1):26–30.

    Article  PubMed  Google Scholar 

  82. Eryaman Y, Guerin B, Akgun C, et al. Parallel transmit pulse design for patients with deep brain stimulation implants. Magn Reson Med. 2014;73:1896–903.

    Article  PubMed  Google Scholar 

  83. Ladd ME, Quick HH. Reduction of resonant RF heating in intravascular catheters using coaxial chokes. Magn Reson Med. 2000;43:615–9.

    Article  CAS  PubMed  Google Scholar 

  84. Gray RW, Bibens WT, Shellock FG. Simple design changes to wires to substantially reduce MRI-induced heating at 1.5 T: implications for implanted leads. Magn Reson Imaging. 2005;23:887–91.

    Article  PubMed  Google Scholar 

  85. Weiss S, Vernickel P, Schaeffter T, Schulz V, Gleich B. Transmission line for improved RF safety of interventional devices. Magn Reson Med. 2005;54:182–9.

    Article  PubMed  Google Scholar 

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Correspondence to Niels Kuster.

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Prof. Niels Kuster reports grants from CTI - Commission for Technology and Innovation, Switzerland, grants from Schmid & Partner Engineering AG, Switzerland, grants from ZMT Zurich MedTech AG, Switzerland, grants from Siemens Health Care GmbH, Germany, grants from GE Medical Systems, USA, during the conduct of the study; other from Boston Scientific Corp., USA, other from Micro Systems Engineering Inc., USA, other from Med-El, Austria, other from Sorin CRM S.A.S., France, other from Nevro Corp., USA, other from St. Jude Medical Inc., USA.

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Murbach, M., Zastrow, E., Neufeld, E. et al. Heating and Safety Concerns of the Radio-Frequency Field in MRI. Curr Radiol Rep 3, 45 (2015). https://doi.org/10.1007/s40134-015-0128-6

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