Abstract #1903

Traveling Wave Mode Transformation in a Waveguide with High Dielectric Medium for Ultra-High Field MRI

Alexey Tonyushkin^1,2, Andrew J. M. Kiruluta^1,2

¹Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States; ²Physics Dept., Harvard University, Cambridge, MA, United States

Existing ultra-high field MR scanners allow propagation of TE and TM modes in high permittivity dielectrics, but the actual B1 field inside the dielectric can be hard to predict. Here, we present the analysis of B1-field map of traveling waves inside a cylindrical waveguide with a dielectric insert and explain features of B1 field by mode transformation to higher order ones. In practice, the modes diversity depends on the tissue efficient diameter, relative permittivity, conductivity, and the Larmor frequency. A more complicated case of heterogeneous axial symmetric dielectric can be also analyzed using effective permittivity and mode transformation approach.