scholarly journals Real-Time Monitoring of Contact Impedance From Multiple Electrode–Scalp Interfaces During Cerebral Electrical Impedance Tomography

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 95186-95196 ◽  
Author(s):  
Hang Ma ◽  
Haoting Li ◽  
Xuechao Liu ◽  
Weichen Li ◽  
Junying Xia ◽  
...  
Keyword(s):  
Real Time ◽  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Real Time Monitoring ◽  
Contact Impedance ◽  
Impedance Tomography ◽  
Multiple Electrode

Evaluation and Real-Time Monitoring of Data Quality in Electrical Impedance Tomography

2013 ◽  
Vol 32 (11) ◽  
pp. 1997-2005 ◽  
Author(s):  
Yasin Mamatjan ◽  
Bartlomiej Grychtol ◽  
Pascal Gaggero ◽  
Jorn Justiz ◽  
Volker M. Koch ◽  
...  
Keyword(s):  
Data Quality ◽  
Real Time ◽  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Real Time Monitoring ◽  
Impedance Tomography

scholarly journals Fast High-Precision Electrical Impedance Tomography System for Real-Time Perfusion Imaging

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 61570-61580 ◽  
Author(s):  
Weichen Li ◽  
Junying Xia ◽  
Ge Zhang ◽  
Hang Ma ◽  
Benyuan Liu ◽  
...  
Keyword(s):  
Real Time ◽  
Electrical Impedance Tomography ◽  
High Precision ◽  
Perfusion Imaging ◽  
Electrical Impedance ◽  
Impedance Tomography ◽  
Tomography System

scholarly journals Self-Abrading Servo Electrode Helmet for Electrical Impedance Tomography

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7058
Author(s):  
James Avery ◽  
Brett Packham ◽  
Hwan Koo ◽  
Ben Hanson ◽  
David Holder
Keyword(s):  
Acute Stroke ◽  
Electrical Impedance Tomography ◽  
Large Scale ◽  
Electrical Impedance ◽  
Applied Pressure ◽  
High Sensitivity ◽  
Haemorrhagic Stroke ◽  
Contact Impedance ◽  
Impedance Tomography ◽  
Skin Contact

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.

JUSTIFICATION OF POINT ELECTRODE MODELS IN ELECTRICAL IMPEDANCE TOMOGRAPHY

2011 ◽  
Vol 21 (06) ◽  
pp. 1395-1413 ◽  
Author(s):  
MARTIN HANKE ◽  
BASTIAN HARRACH ◽  
NUUTTI HYVÖNEN
Keyword(s):  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Analogous Result ◽  
Real Life ◽  
Point Sources ◽  
Reconstruction Problem ◽  
Contact Impedance ◽  
Impedance Tomography ◽  
Point Electrode ◽  
Complete Electrode Model

The most accurate model for real-life electrical impedance tomography is the complete electrode model, which takes into account electrode shapes and (usually unknown) contact impedances at electrode-object interfaces. When the electrodes are small, however, it is tempting to formally replace them by point sources. This simplifies the model considerably and completely eliminates the effect of contact impedance. In this work we rigorously justify such a point electrode model for the important case of having difference measurements ("relative data") as data for the reconstruction problem. We do this by deriving the asymptotic limit of the complete model for vanishing electrode size. This is supplemented by an analogous result for the case that the distance between two adjacent electrodes also tends to zero, thus providing a physical interpretation and justification of the so-called backscattering data introduced by two of the authors.

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