Medical Physics and Biomedical Engineering


Electrical Impedance Tomography/Neurophysiology

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Electrical Impedance Tomography is a recently developed imaging technique, with which images of the internal impedance of the subject can be rapidly collected with rings of external ECG-type electrodes. It is fast, inexpensive, portable and sensitive to physiological changes which affect electrical impedance properties. For about two decades, satisfactory images have been obtained of changes over time related to gastric emptying and ventilation and cardiac output in the thorax. 

The work of our group at UCL has been to pioneer EIT for imaging brain function. It could be used to image in acute stroke or epileptic seizures, when its portability and low cost would give it unique practical advantages over existing methods such as fMRI. It  could also provide images of fast neural activity in the brain over milliseconds which would constitute a revolutionary advance in neuroscience technology. Innovations in hardware and image reconstruction algorithms enable accurate images to be collected in tanks and in experimental animals with electrodes on the brain; the next challenge is to see if recent technical improvements allow us to collect clinically useful images in human subjects with scalp electrodes.

Key advances
Further reading on EIT of brain function