Incorporation of ADC Information Into SMM-based MREIT for Small Animal Conductivity Imaging

Purpose Several ex vivo studies have reported that the electrical impedance of malignancies is lower than healthy tissues and benign formations [Malich et al, Eur Radiol 10:1555-61 (2000)]. Therefore, in vivo conductivity imaging may have potential applications in tumor diagnosis. Magnetic resonance electrical impedance tomography (MREIT) is an emerging, non-invasive conductivity imaging modality, in which electrical currents are injected into an object and the resulting magnetic flux density distribution is measured using MRI; these MRI measurements are then used to reconstruct the conductivity distribution within the object. Only a very limited number of in vivo MREIT studies have been reported. Restrictions on the (safe) injected current level and total scan time limit the signal-to-noise ratio (SNR) of the MREIT data. To improve the conductivity reconstruction using this lower SNR data, we incorporated additional a priori information. Tuch et al have reported a linear relationship between tissue conductivity and the diffusion tensor [PNAS 98:11697701 (2002)]. Thus, we generated the apparent diffusion coefficient (ADC) map and incorporated this information into the MREIT reconstruction algorithm.