Abstract
Producing a homogenous radiofrequency field within the patient at high field is challenging since the electromagnetic wavelength inside the body is significantly less than the body dimensions. An associated problem is the spatially inhomogeneous electric field that can produce localized thermal hot-spots. The use of transmit array coils, in which the magnitude and phase of the inputs to each element of the array are individually controlled, can significantly improve the RF field uniformity within a patient. Despite the challenges, there are also exciting new designs for RF coils and possibilities to control the RF fields which can only be put into practice at high fields. This chapter explains the basic principles of radiofrequency transmission and reception with specific focus on the challenges of UHF-MR and gives an overview of the state-of-the-art in this rapidly changing field.
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References
Adriany G, van de Moortele PF, Wiesinger F, Moeller S, Strupp JP, Andersen P, Snyder C, Zhang X, Chen W, Pruessmann KP, Boesiger P, Vaughan T, Ugurbil K (2005) Transmit and receive transmission line arrays for 7 Tesla parallel imaging. Magn Reson Med 53:434–445
Adriany G, van de Moortele PF, Ritter J, Moeller S, Auerbach EJ, Akgun C, Snyder CJ, Vaughan T, Ugurbil K (2008) A geometrically adjustable 16-channel transmit/receive transmission line array for improved RF efficiency and parallel imaging performance at 7 Tesla. Magn Reson Med 59:590–597
Behnia B, Webb AG (2004) MRI-monitored electromagnetic heating using iterative feedback control and phase interference mapping. Concepts Magn Reson B 23B:1–15
Behnia B, Suthar M, Webb AG (2002) Closed-loop feedback control of phased-array microwave heating using thermal measurements from magnetic resonance imaging. Concepts Magn Reson B 15:101–110
Blaimer M, Breuer F, Mueller M, Heidemann RM, Griswold MA, Jakob PM (2004) SMASH, SENSE, PILS, GRAPPA: how to choose the optimal method. Top Magn Reson Imaging 15:223–236
Brunner DO, De Zanche N, Paska J, Froehlich J, Pruessmann KP (2008) Traveling wave MR on a whole-body system. International Society for Magnetic Resonance in Medicine, Toronto
Collins CM, Smith MB (2001) Calculations of B1 distribution, SNR, and SAR for a surface coil adjacent to an anatomically-accurate human body model. Magn Reson Med 45:692–699
Collins CM, Yang B, Yang QX, Smith MB (2002a) Numerical calculations of the static magnetic field in three-dimensional multi-tissue models of the human head. Magn Reson Imaging 20:413–424
Collins CM, Yang QX, Wang JH, Zhang X, Liu H, Michaeli S, Zhu XH, Adriany G, Vaughan JT, Anderson P, Merkle H, Ugurbil K, Smith MB, Chen W (2002b) Different excitation and reception distributions with a single-loop transmit-receive surface coil near a head-sized spherical phantom at 300 MHz. Magn Reson Med 47:1026–1028
Collins CM, Liu W, Wang J, Gruetter R, Vaughan JT, Ugurbil K, Smith MB (2004) Temperature and SAR calculations for a human head within volume and surface coils at 64 and 300 MHz. J Magn Reson Imaging 19:650–656
Duyn JH, van GP, Li TQ, de Zwart JA, Koretsky AP, Fukunaga M (2007) High-field MRI of brain cortical substructure based on signal phase. Proc Natl Acad Sci USA 104:11796–11801
Glover GH, Hayes CE, Pelc NJ, Edelstein WA, Mueller OM, Hart HR, Hardy CJ, Odonnell M, Barber WD (1985) Comparison of linear and circular-polarization for magnetic-resonance imaging. J Magn Reson 64:255–270
Griswold MA, Jakob PM, Heidemann RM, Nittka M, Jellus V, Wang J, Kiefer B, Haase A (2002) Generalized autocalibrating partially parallel acquisitions (GRAPPA). Magn Reson Med 47:1202–1210
Haines K, Smith NB, Webb AG (2010) New high dielectric constant materials for tailoring the B1Â +Â distribution at high magnetic fields. J Magn Reson (in press)
Hayes CE, Edelstein WA, Schenck JF, Mueller OM, Eash M (1985) An efficient, highly homogeneous radiofrequency coil for whole-body NMR imaging at 1.5-T. J Magn Reson 63:622–628
Heidemann RM, Ozsarlak O, Parizel PM, Michiels J, Kiefer B, Jellus V, Muller M, Breuer F, Blaimer M, Griswold MA, Jakob PM (2003) A brief review of parallel magnetic resonance imaging. Eur Radiol 13:2323–2337
Hoult DI (2009) The origins and present status of the radio wave controversy in NMR. Concepts Magn Reson A 34:193–216
IEC (2002) International standard, medical equipment—part 2: particular requirements for the safetyof magnetic resonance equipment for medical diagnosis, 2nd revision. International electrotechnical commission 601-2-33
Kang CK, Park CW, Han JY, Kim SH, Park CA, Kim KN, Hong SM, Kim YB, Lee KH, Cho ZH (2009) Imaging and analysis of lenticulostriate arteries using 7.0-Tesla magnetic resonance angiography. Magn Reson Med 61:136–144
Katscher U, Bornert P, Leussler C, van den Brink JS (2003) Transmit SENSE. Magn Reson Med 49:144–150
Katscher U, Bornert P, van den Brink JS (2004) Theoretical and numerical aspects of transmit SENSE. IEEE Trans Med Imaging 23:520–525
Kowalski ME, Behnia B, Webb AG, Jin HM (2002) Optimization of electromagnetic phased-arrays for hyperthermia via magnetic resonance temperature estimation. IEEE Trans Microw Theory Tech 49:1229–1241
Kurpad KN, Wright SM, Boskamp EB (2006) RF current element design for independent control of current amplitude and phase in transmit phased arrays. Concepts Magn Reson B 29B:75–83
Lee RF, Westgate CR, Weiss RG, Newman DC, Bottomley PA (2001) Planar strip array (PSA) for MRI. Magn Reson Med 45:673–683
Lee RF, Hardy CJ, Sodickson DK, Bottomley PA (2004) Lumped-element planar strip array (LPSA) for parallel MRI. Magn Reson Med 51:172–183
Lee W, Boskamp E, Grist T, Kurpad K (2009) Radiofrequency current source (RFCS) drive and decoupling technique for parallel transmit arrays using a high-power metal oxide semiconductor field-effect transistor (MOSFET). Magn Reson Med 62:218–228
Li TQ, van GP, Merkle H, Talagala L, Koretsky AP, Duyn J (2006) Extensive heterogeneity in white matter intensity in high-resolution T2*-weighted MRI of the human brain at 7.0 T. Neuroimage 32:1032–1040
Maderwald S, Ladd SC, Gizewski ER, Kraff O, Theysohn JM, Wicklow K, Moenninghoff C, Wanke I, Ladd ME, Quick HH (2008) To TOF or not to TOF: strategies for non-contrast-enhanced intracranial MRA at 7 T. MAGMA 21:159–167
Metzger GJ, Snyder C, Akgun C, Vaughan T, Ugurbil K, van de Moortele PF (2008) Local B1 + shimming for prostate imaging with transceiver arrays at 7T based on subject-dependent transmit phase measurements. Magn Reson Med 59:396–409
Monninghoff C, Maderwald S, Theysohn JM, Kraff O, Ladd SC, Ladd ME, Forsting M, Quick HH, Wanke I (2009) Evaluation of intracranial aneurysms with 7 T versus 1.5 T time-of-flight MR angiography—initial experience. Rofo 181:16–23
Pennes HH (1948) Analysis of skin, muscle and brachial arterial blood temperatures in the resting normal human forearm. Am J Physiol 155:459
Pruessmann KP, Weiger M, Scheidegger MB, Boesiger P (1999) SENSE: sensitivity encoding for fast MRI. Magn Reson Med 42:952–962
Roemer PB, Edelstein WA, Hayes CE, Souza SP, Mueller OM (1990) The NMR phased array. Magn Reson Med 16:192–225
Schmitt M, Potthast A, Sosnovik DE, Polimeni JR, Wiggins GC, Triantafyllou C, Wald LL (2008) A 128-channel receive-only cardiac coil for highly accelerated cardiac MRI at 3 Tesla. Magn Reson Med 59:1431–1439
Snyder CJ, DelaBarre L, Metzger GJ, van de Moortele PF, Akgun C, Ugurbil K, Vaughan JT (2009) Initial results of cardiac imaging at 7 Tesla. Magn Reson Med 61:517–524
Sodickson DK, Manning WJ (1997) Simultaneous acquisition of spatial harmonics (SMASH): fast imaging with radiofrequency coil arrays. Magn Reson Med 38:591–603
Sodickson DK, McKenzie CA (2001) A generalized approach to parallel magnetic resonance imaging. Med Phys 28:1629–1643
Sullivan D (1991) Mathematical-methods for treatment planning in deep regional hyperthermia. IEEE Trans Microw Theory Tech 39:864–872
Tkac I, Oz G, Adriany G, Ugurbil K, Gruetter R (2009) In vivo 1H NMR spectroscopy of the human brain at high magnetic fields: metabolite quantification at 4T vs. 7T. Magn Reson Med 62:868–879
Traficante DD (1989) Impedance: what it is and why it must be matched. Concepts Magn Reson 1:73–92
van de Moortele PF, Akgun C, Adriany G, Moeller S, Ritter J, Collins CM, Smith MB, Vaughan JT, Ugurbil K (2005) B1 destructive interferences and spatial phase patterns at 7 T with a head transceiver array coil. Magn Reson Med 54:1503–1518
van Elderen SG, Versluis MJ, Webb AG, Westenberg JJ, Doornbos J, Smith NB, de RA, Stuber M (2009) Initial results on in vivo human coronary MR angiography at 7 T. Magn Reson Med 62:1379–1384
Vaughan JT, Hetherington HP, Otu JO, Pan JW, Pohost GM (1994) High frequency volume coils for clinical NMR imaging and spectroscopy. Magn Reson Med 32:206–218
Vaughan JT, Adriany G, Snyder CJ, Tian J, Thiel T, Bolinger L, Liu H, DelaBarre L, Ugurbil K (2004) Efficient high-frequency body coil for high-field MRI. Magn Reson Med 52:851–859
Vaughan T, DelaBarre L, Snyder C, Tian J, Akgun C, Shrivastava D, Liu W, Olson C, Adriany G, Strupp J, Andersen P, Gopinath A, van de Moortele PF, Garwood M, Ugurbil K (2006) 9.4T human MRI: preliminary results. Magn Reson Med 56:1274–1282
Vaughan JT, Snyder CJ, DelaBarre LJ, Bolan PJ, Tian J, Bolinger L, Adriany G, Andersen P, Strupp J, Ugurbil K (2009) Whole-body imaging at 7T: preliminary results. Magn Reson Med 61:244–248
Versluis MJ, Tsekos N, Smith NB, Webb AG (2009) Simple RF design for human functional and morphological cardiac imaging at 7tesla. J Magn Reson 200:161–166
Wang J, Yang QX, Zhang X, Collins CM, Smith MB, Zhu XH, Adriany G, Ugurbil K, Chen W (2002) Polarization of the RF field in a human head at high field: a study with a quadrature surface coil at 7.0 T. Magn Reson Med 48:362–369
Wang Z, Lin JC, Mao W, Liu W, Smith MB, Collins CM (2007) SAR and temperature: simulations and comparison to regulatory limits for MRI. J Magn Reson Imaging 26:437–441
Webb AG, Collins CM, Kan HE, Versluis M, Smith NB (2010) Magn Reson Med 63:297–302
Weihrauch M, Wust P, Weiser M, Nadobny J, Eisenhardt S, Budach V, Gellermann J (2007) Adaptation of antenna profiles for control of MR guided hyperthermia (HT) in a hybrid MR-HT system. Med Phys 34:4717–4725
Wright SM, Magin RL, Kelton JR (1991) Arrays of mutually coupled receiver coils: theory and application. Magn Reson Med 17:252–268
Wust P, Nadobny J, Felix R, Deuflhard P, Louis A, John W (1991) Strategies for optimized application of annular-phased-array systems in clinical hyperthermia. Int J Hyperthermia 7:157–173
Yacoub E, Shmuel A, Pfeuffer J, van de Moortele PF, Adriany G, Andersen P, Vaughan JT, Merkle H, Ugurbil K, Hu X (2001) Imaging brain function in humans at 7 Tesla. Magn Reson Med 45:588–594
Yang QX, Mao W, Wang J, Smith MB, Lei H, Zhang X, Ugurbil K, Chen W (2006) Manipulation of image intensity distribution at 7.0 T: passive RF shimming and focusing with dielectric materials. J Magn Reson Imaging 24:197–202
Zhang XZ, Webb A (2004) Design of a capacitively decoupled transmit/receive NMR phased array for high field microscopy at 14.1 T. J Magn Reson 170:149–155
Zwanenburg JJ, Hendrikse J, Takahara T, Visser F, Luijten PR (2008) MR angiography of the cerebral perforating arteries with magnetization prepared anatomical reference at 7 T: comparison with time-of-flight. J Magn Reson Imaging 28:1519–1526
Acknowledgments
The MATLAB code used to generate values of dielectric constant versus frequency (http://pennstatehershey.org/web/nmrlab/resources/software/rftools) were provided by Chris Collins and Sukhoon Oh from the Penn State Center for NMR Research. Coil photographs were generously provided by Mark Ladd from the Erwin L. Hahn Institute, University of Essen-Duisberg and Chris Collins. Figures were also provided by Figures were kindly provided by Thomas Vaughan, Pierre-Francois van der Moortele, and Gregor Adriany from the Center for Magnetic Resonance Research, University of Minnesota.
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Webb, A.G. (2012). Radiofrequency Coils. In: Hennig, J., Speck, O. (eds) High-Field MR Imaging. Medical Radiology(). Springer, Berlin, Heidelberg. https://doi.org/10.1007/174_2010_131
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DOI: https://doi.org/10.1007/174_2010_131
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