Author/Editor     Mikac, Urša; Demšar, Franci; Beravs, Katarina; Serša, Igor
Title     Magnetic resonance imaging of alternating electric currents
Type     članek
Source     Magn Reson Imaging
Vol. and No.     Letnik 19, št. 6
Publication year     2001
Volume     str. 845-56
Language     eng
Abstract     Electric Current Density Imaging (CDI) is a new modality of magnetic resonance imaging that enables electric current distribution imaging in conductive samples containing water. So far, two CDI techniques have been in use: DC-CDI operating at zero frequency and RF-CDI operating at the RF Larmor frequency. In this paper we present a new CDI technique, which extends the CDI frequency range to alternating electric currents (AC-CDI). First, a theoretical model for the electric current response to the alternating voltage is presented. Later, this model is used for the frequency analysis of the AC-CDI sequence. Additionally, the effect of off-resonance spins and imperfect refocusing RF pulses on the stability of the AC-CDI sequence and the echo formation is studied. The new theory is verified by experiments on a model system and compared to the other two methods: DC-CDI and RF-CDI. Finally, an application of the AC-CDI sequence to biological systems is demonstrated by an experiment on a wood twig in which an increase of approximately 30% was obtained at AC as compared to DC electric current.
Descriptors     ELECTRICITY
MAGNETIC RESONANCE IMAGING
MODELS, THEORETICAL
PHANTOMS, IMAGING
WOOD