Electrical Impedance Tomography/Neurophysiology



Group leader : David Holder

Kirill Aristovich

Tom Dowrick

James Avery

Mayo Faulkner

Nir Goren

Sana Hannan

Markus Jehl

Ilya Tarontin

Anna Witkowska-Wrobel

Rebecca Yerworth

Zhou Zhou

Research - Electrical Impedance Tomography of brain function

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

  • Development of idea that EIT could provide tomographic images of fast electrical activity in the brain and so provide a uniquely new method to test theories in computational neuroscience (Holder, 1987)
  • Demonstration that EIT with the Sheffield Mark 1 EIT system could produce reproducible EIT images of stroke (Holder, 1992), epileptic seizures, functional activity (Holder et al, 1996, Oh et al, 2011) and the phenomenon of spreading depression which is thought to underlie migraine (Boone et al, 1994) in anaesthetised experimental animals (rats or rabbits) with a ring of electrodes on exposed brain
  • A recent breakthrough has been the production of the first tomographic images of fast neural activity during cortical evoked activity in the anaesthetized rat (Aristovich et al, 2014).