Electrical Impedance Tomography of Epilepsy

Study Overview
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Brief Summary
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The purpose of this study is to determine if Electrical Impedance Tomography (EIT) can produce reproducible and accurate images in people with epilepsy compared to existing standards such as MRI, CT or EEG. Electrical Impedance Tomography is a relatively new medical imaging method, which has the potential to provide novel images of brain function. It is fast, portable, safe and inexpensive, but currently has a relatively poor spatial resolution. It produces images of the internal electrical impedance of a subject with epilepsy using rings of ECG like electrodes on the skin, intracranial electrode mats or deep electrodes implemented surgically as part of clinical assessment. EIT recording will take place in parallel with the routine recording on the ward. Following completion of the recording, the EIT images will subsequently be analysed and compared to other imaging data for accuracy.

Detailed Description
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Electrical Impedance Tomography (EIT) is a novel medical imaging method in which tomographic images are rapidly produced using electrodes placed around the body. The principal applicant's group has demonstrated that EIT can rapidly image functional brain activity in stroke, epilepsy and normal activity in animal models and has developed instrumentation and image reconstruction algorithms which work well in head-shaped tanks. The principal aim of this research is to optimise and assess accuracy of Electrical Impedance Tomography (EIT) using scalp electrodes, intracranial electrode mats or deep electrodes in imaging epilepsy in human participants. If successful, EIT has the potential to provide a new portable imaging unit. It could be used with scalp electrodes and enable imaging of the onset and propagation of seizures in 3D. Image quality would be better with intracranial electrode mats or depth electrodes that are already implanted in people with severe epilepsy who are being evaluated for epilepsy surgery. For both electrode types, the new 3D information will enable better diagnosis and so targeting of drug treatment. It could also pave the way to suppression of seizures by deep brain electrical stimulation which could transform management in severe intractable epilepsy.It can offer the same benefits in imaging in epilepsy in neonates and infants. Patients diagnosed with epilepsy will be asked to participate in the epilepsy EIT study, then up to 32 electrodes will be applied on the subjects' scalp or the EIT systems will be linked to the existing EEG video recording systems and EIT will be recorded at the same time using some or all of the available intracranial electrodes. It may also use some scalp EEG electrode placed on the scalp for clinical or research purposes. Following completion of the recording, scalp electrodes and any paste will be removed, the EIT system will be disconnected from the videoEEG. Collected data will be analysed and compared to other imaging data.

Official Title
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Imaging Stroke, Epilepsy and Evoked Potentials in the Brain Using Electrical Impedance Tomography

Conditions
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Epilepsy

Intervention / Treatment
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* Device: Electrical Impedance Tomography


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Any patient with epilepsy with either active seizures or interictal EEG changes (for scalp electrodes group) Any patient with epilepsy with either active seizures under evaluation for epilepsy surgery (for intracranial electrodes group) Ability to give informed consent Exclusion Criteria: none

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Epilepsy with intracranial electrodes<br>Electrical Impedance Tomography with depth electrodes or intracranial electrode mats | Device: Electrical Impedance Tomography<br>* EIT comprises of a box of electronics similar in size to a video recorder, laptop computer and leads which link typically to 16 or 32 external ECG-like electrodes placed around the subject. Images are generated by applying tiny electrical signals through some electrodes and recording the resulting signals at others. The signals applied are completely safe, within established British and EU safety limits and cannot be felt. For intracranial electrode studies, the EIT systems will be linked to the existing EEG video recording systems and EIT will be recorded at the same time using some or all of the available intracranial electrodes.<br>* Other names: EIT;|
| Epilepsy with scalp electrodes<br>Electrical Impedance Tomography with scalp electrodes | Device: Electrical Impedance Tomography<br>* EIT comprises of a box of electronics similar in size to a video recorder, laptop computer and leads which link typically to 16 or 32 external ECG-like electrodes placed around the subject. Images are generated by applying tiny electrical signals through some electrodes and recording the resulting signals at others. The signals applied are completely safe, within established British and EU safety limits and cannot be felt. For intracranial electrode studies, the EIT systems will be linked to the existing EEG video recording systems and EIT will be recorded at the same time using some or all of the available intracranial electrodes.<br>* Other names: EIT;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| EIT images accuracy |  | three years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Electrical Impedance Tomography, EIT, Epilepsy