In-vivo pilot study at 3 Tesla: Feasibility of Electric Properties Tomography in a rat model of stroke

Abstract

BackgroundElectrical Properties Tomography (EPT) is a new sequence which delivers information on tissue electrical conductivity. It has been mostly used for tumor imaging. Ischemic stroke is another promising application. The aim of this study was to demonstrate the feasibility of EPT in a rodent model of stroke. MethodsWistar rats with and without temporary middle cerebral occlusion (MCAo) were examined in a 3T scanner. EPT was performed using a Steady-State Free-Precession (SSFP) sequence. From the transceive phase ɸ of these SSFP scans, conductivity σ was estimated by the equation σ = Δɸ/(2μ0ω) with Δ the Laplacian operator, μ0 the magnetic permeability, and ω the Larmor frequency. Subsequently, a median filter was applied. ResultsHealthy cortical grey matter, white matter and cerebrospinal fluid showed significantly different conductivity (0.83 ± 0.14 S/m, 0.63 ± 0.06 S/m, 2.33 ± 0.49 S/m, p < 0.05). Infarcted tissue exhibited increased conductivity (1.937 ± 1.347 vs. 0.782 ± 0.429 S/m, p < 0.05). ConclusionEPT is feasible in a rodent model of stroke. Infarcted tissue after MCAo exhibited increased conductivity. Further in-vivo experiments with examination of the influence of reperfusion status and temporal evolution of the infarcted areas should be conducted.