In vivo magnetic resonance electrical impedance tomography of canine brain: disease model study of ischemia and abscess

Purpose: In this study, we performed in vivo disease model animal experiments to validate the MREIT technique in terms of its capability to produce a conductivity contrast corresponding to brain ischemia and abscess. Methods: Injecting 5 mA imaging currents into the head of an anesthetized dog, we collected induced magnetic flux density data using a 3T MRI scanner. Applying the harmonic B_z algorithm to the data, we reconstructed scaled conductivity images providing conductivity contrast information. To investigate any change of electrical conductivity due to brain diseases of ischemia and abscess, we scanned an animal with such a regional brain disease along with a separate prior scan of the same animal having no disease model. Results: In the brain ischemic region, conductivity images show a significantly decreased contrast. The conductivity images of brain abscess show a significantly increased contrast, which is not apparent in the normal brain. Conclusions: The results indicate that MREIT conductivity images provide meaningful diagnostic information that is not available from other imaging modalities. We suggest further animal imaging experiments with numerous disease models to support clinical significance of the MREIT conductivity imaging method.