Self-abrading servo electrode helmet for electrical impedance tomography
File(s)sensors-20-07058-v2.pdf (5.11 MB)
Published version
OA Location
Author(s)
Avery, James
Packham, Brett
Koo, Hwan
Hanson, Ben
Holder, David
Type
Journal Article
Abstract
Electrical Impedance Tomography (EIT) is a medical imaging technique which has the potential to reduce time to treatment in acute stroke by rapidly differentiating between ischaemic and haemorrhagic stroke. The potential of these methods has been demonstrated in simulation and phantoms, it has not yet successfully translated to clinical studies, due to high sensitivity to errors in scalp electrode mislocation and poor electrode-skin contact. To overcome these limitations, a novel electrode helmet was designed, bearing 32 independently controlled self-abrading electrodes. The contact impedance was reduced through rotation on an abrasive electrode on the scalp using a combined impedance, rotation and position feedback loop. Potentiometers within each unit measure the electrode tip displacement within 0.1 mm from the rigid helmet body. Characterisation experiments on a large-scale test rig demonstrated that approximately 20 kPa applied pressure and 5 rotations was necessary to achieve the target 5 kΩ contact impedance at 20 Hz. This performance was then replicated in a simplified self-contained unit where spring loaded electrodes are rotated by servo motors. Finally, a 32-channel helmet and controller which sequentially minimised contact impedance and simultaneously located each electrode was built which reduced the electrode application and localisation time to less than five minutes. The results demonstrated the potential of this approach to rapidly apply electrodes in an acute setting, removing a significant barrier for imaging acute stroke with EIT.
Date Issued
2020-12-09
Date Acceptance
2020-12-04
Citation
Sensors, 2020, 20 (24)
ISSN
1424-8220
Publisher
MDPI AG
Journal / Book Title
Sensors
Volume
20
Issue
24
Copyright Statement
©2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open accessarticle distributed under the terms and conditions of the Creative Commons Attribution(CC BY) license (http://creativecommons.org/licenses/by/4.0/).
License URL
Sponsor
Imperial College Healthcare NHS Trust- BRC Funding
Grant Number
RDB04
Subjects
Science & Technology
Physical Sciences
Technology
Chemistry, Analytical
Engineering, Electrical & Electronic
Instruments & Instrumentation
Chemistry
Engineering
electrical impedance tomography
stroke
brain imaging
bioimpedance electrodes
MODELING ERRORS
STROKE
EIT
HEAD
POSITIONS
DISEASE
SYSTEM
MESHES
ARRAY
EEG
bioimpedance electrodes
brain imaging
electrical impedance tomography
stroke
Analytical Chemistry
0301 Analytical Chemistry
0805 Distributed Computing
0906 Electrical and Electronic Engineering
0502 Environmental Science and Management
0602 Ecology
Publication Status
Published
Article Number
ARTN 7058