SNR calculation in Magnetic Resonance experiments requires the knowledge of biological sample resistance value. In dependence on system geometry, many authors studied sample-coil interaction by using quasi-static approach, with very simple coil geometry (circular or square) and homogeneous infinitely long cylinders, spheres or half-space as an approximation of the sample geometry. However, in real MR experiments, both shape and dimensions can be very different respect to these coil and sample models. Moreover, quasi-static method fails at high field MR imaging. In this paper we propose a theoretical algorithm for sample resistance estimation which use a numerical solver based on Finite-Difference Time-Domain method for simulating MR systems, without approximations in sample and coil geometries. Comparison with experimental data, performed on a home-built simple coil, demonstrated the great accuracy of the developed algorithm. The proposed method can be used as a tool to estimate sample resistance values for more complex geometries.
Electromagnetic Method for Sample Induced Resistance Calculation of Magnetic Resonance Coils
Giovannetti G;Hartwig V;Landini L;Benassi A
2010
Abstract
SNR calculation in Magnetic Resonance experiments requires the knowledge of biological sample resistance value. In dependence on system geometry, many authors studied sample-coil interaction by using quasi-static approach, with very simple coil geometry (circular or square) and homogeneous infinitely long cylinders, spheres or half-space as an approximation of the sample geometry. However, in real MR experiments, both shape and dimensions can be very different respect to these coil and sample models. Moreover, quasi-static method fails at high field MR imaging. In this paper we propose a theoretical algorithm for sample resistance estimation which use a numerical solver based on Finite-Difference Time-Domain method for simulating MR systems, without approximations in sample and coil geometries. Comparison with experimental data, performed on a home-built simple coil, demonstrated the great accuracy of the developed algorithm. The proposed method can be used as a tool to estimate sample resistance values for more complex geometries.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
