Magnetohydrodynamic Flow Imaging Using Spin-Echo Pulse Sequence

Abstract

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 error is 29 % for 1 mA injected current with 20 ms duration when signal to noise ratio of the MHD phase measurements is 35. It is possible to obtain information about the MHD flow and determine viscosity inhomogeneities inside the imaged medium by using the MHD phase and velocity distributions. Design of a pulse sequence that generates an MHD flow with constant velocity at each data acquisition period may reduce the reconstruction error. By this way, the method may be utilized in imaging of liquid media, such as blood or cerebrospinal fluid surrounded by excitable tissue.