MRI image enhancement using Biot--Savart law at 3 tesla

Abstract

Abstract:Coil sensitivity is considered as the most valuable data in the parallel reconstruction of magnetic resonance imaging (MRI). In this study, a novel coil sensitivity map extraction method is introduced for spatially fixed phased array coils. The proposed technique uses the Biot-Savart law with coil internal shape information and low-resolution phase image data to form sensitivity maps. The performance of this method is tested in a parallel image reconstruction task, using the sensitivity-encoding (SENSE) technique. Under the quasi-static assumption and using the duality principle, we computed the sensitivity maps of a phased-array head coil and reconstructed full FOV images. The experiments show that the resulting image quality is higher in terms of sharpness, artifact level, homogeneity, etc. than existing methods that use sensitivity maps calculated only from low-resolution image data. Moreover, several simulations were conducted using an electromagnetic simulation software tool to theoretically prove the success of the proposed technique.Our simulation results indicate that the success of the method depends heavily on the size of the coil elements. A new method for calculation of sensitivity maps is briefly introduced, which increases image quality and homogeneity while reducing the artifacts.

Design and Testing of a Radiofrequency Ellipsoidal Helmholtz Coil in Contrast with a Circular Pair for Nuclear Magnetic Resonance

“…It can be seen that at f o , the transfer of power from the primary to the secondary coil is optimal. This is a particularity of the inductive coupling which is widely used in RF [25][26]. For the other frequencies f 1 and f 2 , the currents I 1 and I 2 have a maximum value and the difference between the two modes remains at the phase level.…”

Design and Modeling of a Radiofrequency Coil Derived from a Helmholtz Structure

“…For the calculation of the electromagnetic field (B1) produced by the proposed structure which consists of two symmetric elements and has small dimensions compared to the wavelength, the superposition principle can be applied to obtain the total electromagnetic field [17]. The component along the y axis of the magnetic field shown in Figure 1 produced by a thin ring of wire, of radius a, positioned in the xz plane, centered on the origin O and carrying a current I is easily determined by using Biot-Savart's law [18]:…”