Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2017 Aug 2;28(11):689-693.
doi: 10.1097/WNR.0000000000000823.

Real-time imaging of epileptic seizures in rats using electrical impedance tomography

Lei Wang  1 , Yang Sun, Xinmin Xu, Xiuzhen Dong, Feng Gao
Affiliations

Real-time imaging of epileptic seizures in rats using electrical impedance tomography

Lei Wang et al. Neuroreport. .

Abstract

The presence of multiple or diffuse lesions on imaging is a contraindication to surgery for patients with intractable epilepsy. Theoretically, as a functional imaging technique, electrical impedance tomography (EIT) can accurately image epileptic foci. However, most current studies are limited to examining epileptic spikes and few studies use EIT for real-time imaging of seizure activity. Moreover, little is known about changes in electrical impedance during seizures. In this study, we used EIT to monitor seizure progression in real time and analyzed changes in electrical impedance during seizures. EIT and electroencephalography data were recorded simultaneously in rats. Sixty-three seizures were recorded from the cortices of eight rats. During 54 seizures, the average impedance decreased by between 4.86 and 9.17% compared with the baseline. Compared with the control group, the average impedance of the experimental group decreased significantly (P=0.004). Our results indicate that EIT can be used to detect and image electrical impedance reduction within lesions during epileptic seizures.

PubMed Disclaimer

Figures

Fig. 1
Fig. 1
Electrode positions for electrical impedance tomography (EIT) and electroencephalography (EEG) imaging. EIT and EEG electrodes are in the dashed box and the nondashed box, respectively.
Fig. 2
Fig. 2
(a) Average resistivity value and reconstructed impedance changes in an experimental rat (no. 2). Plots of the average resistivity value against time (top). Seizure onset and offset are marked by vertical solid lines. Reconstructed impedance changes during ictal activity (middle). At the middle right, image orientation is indicated in the diagram with the directions, anterior (A), left (L), posterior (P), and right (R). The spectral bar on the right represents resistivity states and associated colors, from decreased resistivity (red) to normal baseline intensity (green) to increased resistivity (blue). The numbers, 0.5 and −0.5, are the upper and lower limits of the resistivity values, respectively. Simultaneously recorded EEG segment during the ictal period from Fp1 and Fp2 electrodes (bottom). (b) Reconstruction of impedance changes in a control rat (no. 5; top) and plots of the corresponding average resistivity value against time (bottom).
Fig. 3
Fig. 3
Tomographic images of impedance changes showing the onset and progression of seizure activity in eight rats.
See this image and copyright information in PMC

References

    1. Spencer S, Huh L. Outcomes of epilepsy surgery in adults and children. Lancet Neurol 2008; 7:525–537. - PubMed
    1. O’Brien TJ, So EL, Mullan BP, Hauser MF, Brinkmann BH, Bohnen NI, et al. Subtraction ictal SPECT co-registered to MRI improves clinical usefulness of SPECT in localizing the surgical seizure focus. Neurology 1998; 50:445–454. - PubMed
    1. la Fougère C, Rominger A, Förster S, Geisler J, Bartenstein P. PET and SPECT in epilepsy: a critical review. Epilepsy Behav 2009; 15:50–55. - PubMed
    1. Xu CH, Wang L, Shi XT, You FS, Fu F, Liu RG, et al. Real-time imaging and detection of intracranial haemorrhage by electrical impedance tomography in a piglet model. J Int Med Res 2010; 38:1596–1604. - PubMed
    1. Abascal JF, Arridge SR, Bayford RH, Holder DS. Comparison of methods for optimal choice of the regularization parameter for linear electrical impedance tomography of brain function. Physiol Meas 2008; 29:1319–1334. - PubMed