MATERIAL INFLUENCES IN MR TOMOGRAPHY, MEASUREMENT AND SIMULATION

Miroslav Steinbauer – Radek Kubásek – Karel Bartušek

   Materials with different electrical conductivity and/or magnetic susceptibility can cause deformation of magnetic field in MR tomograph, resulting in errors in obtained image. Using simulation and experimental verification we can solve the effect of changes in homogeneity of static and HF magnetic fields caused by specimen made from conductive and/or magnetic material in MR tomograph. This paper describes theoretical base and experimental measurement of the magnetic resonance imaging method for susceptibility measurement. Below in this paper we will discuss measuring technique, which is suitable for substances with no signal in MR tomography. The method uses deformation of magnetic induction field in specimen vicinity. For MR purposes it is necessary to immerse specimen into reference medium with measurable MR signal (demineralized water is suitable). Finally, measured data obtained by means of the method using MRI will be shown. Shape of magnetic field changed by specimen impact (reaction field) we measure by means of Gradient Echo (GE) measuring method.

Keywords: NMR, MR, Material influences, Susceptibility, Magnetic field deformation

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