Analysis of wave behavior in lossy dielectric samples at high field
Corresponding Author
Qing X. Yang
Center for NMR Research, Department of Radiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
Center for NMR Research, NMR/MRI Building, Department of Radiology H066, Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033===Search for more papers by this authorJinghua Wang
Center for NMR Research, Department of Radiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
Search for more papers by this authorXiaoliang Zhang
Center for MR Research, Department of Radiology, School of Medicine, University of Minnesota, Minneapolis, Minnesota
Search for more papers by this authorChristopher M. Collins
Center for NMR Research, Department of Radiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
Search for more papers by this authorMichael B. Smith
Center for NMR Research, Department of Radiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
Search for more papers by this authorHaiying Liu
Center for MR Research, Department of Radiology, School of Medicine, University of Minnesota, Minneapolis, Minnesota
Search for more papers by this authorXiao-Hong Zhu
Center for MR Research, Department of Radiology, School of Medicine, University of Minnesota, Minneapolis, Minnesota
Search for more papers by this authorJ. Thomas Vaughan
Center for NMR Research, Department of Radiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
Search for more papers by this authorKamil Ugurbil
Center for MR Research, Department of Radiology, School of Medicine, University of Minnesota, Minneapolis, Minnesota
Search for more papers by this authorWei Chen
Center for MR Research, Department of Radiology, School of Medicine, University of Minnesota, Minneapolis, Minnesota
Search for more papers by this authorCorresponding Author
Qing X. Yang
Center for NMR Research, Department of Radiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
Center for NMR Research, NMR/MRI Building, Department of Radiology H066, Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033===Search for more papers by this authorJinghua Wang
Center for NMR Research, Department of Radiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
Search for more papers by this authorXiaoliang Zhang
Center for MR Research, Department of Radiology, School of Medicine, University of Minnesota, Minneapolis, Minnesota
Search for more papers by this authorChristopher M. Collins
Center for NMR Research, Department of Radiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
Search for more papers by this authorMichael B. Smith
Center for NMR Research, Department of Radiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
Search for more papers by this authorHaiying Liu
Center for MR Research, Department of Radiology, School of Medicine, University of Minnesota, Minneapolis, Minnesota
Search for more papers by this authorXiao-Hong Zhu
Center for MR Research, Department of Radiology, School of Medicine, University of Minnesota, Minneapolis, Minnesota
Search for more papers by this authorJ. Thomas Vaughan
Center for NMR Research, Department of Radiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
Search for more papers by this authorKamil Ugurbil
Center for MR Research, Department of Radiology, School of Medicine, University of Minnesota, Minneapolis, Minnesota
Search for more papers by this authorWei Chen
Center for MR Research, Department of Radiology, School of Medicine, University of Minnesota, Minneapolis, Minnesota
Search for more papers by this authorAbstract
Radiofrequency (RF) field wave behavior and associated nonuniform image intensity at high magnetic field strengths are examined experimentally and numerically. The RF field produced by a 10-cm-diameter surface coil at 300 MHz is evaluated in a 16-cm-diameter spherical phantom with variable salinity, and in the human head. Temporal progression of the RF field indicates that the standing wave and associated dielectric resonance occurring in a pure water phantom near 300 MHz is greatly dampened in the human head due to the strong decay of the electromagnetic wave. The characteristic image intensity distribution in the human head is the result of spatial phase distribution and amplitude modulation by the interference of the RF traveling waves determined by a given sample-coil configuration. The numerical calculation method is validated with experimental results. The general behavior of the RF field with respect to the average brain electrical properties in a frequency range of 42–350 MHz is also analyzed. Magn Reson Med 47:982–989, 2002. © 2002 Wiley-Liss, Inc.
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