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 |