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

Abstract

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. ConclusionsThe 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.

Current‐induced alternating reversed dual‐echo‐steady‐state for joint estimation of tissue relaxation and electrical properties

“…Unless stated otherwise, the following parameters in all numerical simulations were held by: TR ¼ 18 ms, TE ECHO /TE FID ¼ 2.5 ms/15.5 ms, and a 1 =a 2 ¼ 50 /20 . Nominal parameters were set to: Q nom ¼ fT 10 ; T 20 ; f c;10 ; f c;20 g ¼ f500 ms; 100 ms; 10 ; 5 g.…”

“…Electrical conductivity of biological tissues and organs is well known to vary with their physiological and pathological states, potentially providing valuable diagnostic information . Magnetic resonance electrical impedance tomography (MREIT) is to achieve high resolution, cross‐sectional conductivity (σ) distribution. Current pulses in sync with an MR pulse sequence are applied to an electrically conducting subject through a pair of surface electrodes, inducing internal distribution of magnetic flux density ( B : B x , B y , B z ).…”

A feasibility study of magnetic resonance electrical impedance tomography for prostate cancer detection

“…In this case, the ill-posedness of traditional EIT is eliminated, since a huge number of measurements can be acquired not only over the surface but also inside the subject. Experimental MREIT research has been conducted extensively on biological tissue phantoms (Oh et al 2005), postmortem subjects (Kim et al 2007), in vivo animal models (Muftuler et al 2006, Kim et al 2008, 2011) and in vivo human models (Kim et al 2009, Meng et al 2012). Kim et al (2010) have applied MREIT to image the conductivity distribution of a male canine pelvis and the reconstructed conductivity images effectively distinguish different organs of the pelvis including the prostate, sacrum, rectum, and surrounding muscles.…”