Magnetic Resonance Signal Analysis in Inhomogenous Magnetic Fields

Nuclear Magnetic Resonance (NMR) systems with inhomogenous main magnetic fields have been satisfactorily used to explore material properties. So that, imaging of biological tissues using Magnetic Resonance Imaging (MRI) systems with inhomogenous main magnetic fields could be explored. In this work, magnetic resonance (MR) signal deviation due to inhomogeneity in the main magnetic field of a MRI system is investigated. This analysis gives the understanding of the effect of inhomogeneity in magnetic field to signal decay time, energy and peak. Using these parameters, suitability of specific MRI hardware designed for inhomogeneous magnetic field can be analyzed. In other words, using proposed analysis, the inhomogeneity tolerance of a specific hardware can be found. Meanwhile, given the inhomogeneity distribution, the hardware design parameters can be selected accordingly to acquire MR signal.
11th International Congress of the IUPESM/World Congress on Medical Physics and Biomedical Engineering


RF Coil Design for MRI Applications in Inhomogeneous Main Magnetic Fields
Yılmaz, Ayşen; Eyueboglu, B. M. (2006-09-01)
Conventional Magnetic Resonance Imaging (MRI) techniques require homogeneous main magnetic fields. However, MRI applications that are executed in inhomogenous main magnetic fields have been developed in recent years. In this study, RF coil geometries are designed for MRI applications in inhomogeneous magnetic fields. Method of moments is used to obtain the current density distribution on a predefined surface that can produce a desired magnetic field, which is perpendicular to the given inhomogenous main mag...
Magnetic Resonance Imaging in Inhomogeneous Magnetic Fields with Noisy Signal
Arpinar, V. E.; Eyüboğlu, Behçet Murat (2008-11-27)
In this study, an image reconstruction algorithm for a Magnetic Resonance Imaging (MRI) system with inhomogeneous magnetic fields is proposed. The proposed reconstruction algorithm uses spatial distributions of main magnetic field, Radio Frequency (RF) and gradient fields as inputs, together with the pulse sequence and the noisy Magnetic Resonance (MR) signal. To calculate the noise signal, noise model for MRI with homogeneous fields is extended for inhomogeneous magnetic fields. Using this embedded noise m...
Magnetic resonance imaging of polymer melt flows
Uludağ, Yusuf; Powell, RL; Barall, G (2000-01-01)
A tubular rheometry that is based on obtaining velocity profiles by nuclear magnetic resonance imaging (NMRI) and measuring pressure drop of the flow is used for the polymer melts. This technique allows one to get viscosity data potentially over many decades of shear rate region in a single measurement. In this study, we examined polyethylene melt as the flow medium. Despite the low shear rates attained, our results reveal that this non-invasive and non-destructive method is promising for constructing an on...
Magnetohydrodynamic Flow Imaging Using Spin-Echo Pulse Sequence
Eroğlu, Hasan Hüseyin; SADIGHI, MEHDI; Eyüboğlu, Behçet Murat (2019-04-24)
In this study, magnetohydrodynamic (MHD) flow of conductive liquids due to injection of electrical current during magnetic resonance imaging (MRI) is investigated. A spin-echo based MRI pulse sequence is proposed to image the MHD flow. Magnetic resonance (MR) phase effects of the MHD flow is related to the MRI pulse parameters and injected current. Average velocity distributions of the MHD flow are reconstructed using the MR phase images. The method is validated by numerical simulations. The reconstruction ...
Radial motion of highly conducting sphere in magnetic field
Gurcan, OD; Mirnov, VV; Ucer, D (2000-05-01)
Radial motion of a highly conducting sphere in external magnetic field is considered. It both perturbs the external magnetic field and generates an electric field. Exact analytic solution has been obtained previously for a uniformly expanding sphere. In the present paper a new exact solution is derived which is valid not only for expansion but for contraction as well. It allows us to calculate analytically the total electromagnetic energy irradiated by the sphere involved in periodical radial motion with ar...
Citation Formats
V. E. Arpinar and B. M. Eyüboğlu, “Magnetic Resonance Signal Analysis in Inhomogenous Magnetic Fields,” Munich, GERMANY, 2009, vol. 25, Accessed: 00, 2020. [Online]. Available: