Electro Interstitial Scan

What is EIS System
Definition and Performances
thumb
The EIS system provides an electrical signal corresponding to the status of a patient's physiological parameters: , tissue PCO2, sympathetic system activity and microcirculation blood flow.
EIS Intended uses
Monitoring of treatment with the conventional methods.
In adjunct to the diagnosis of ADHD children with the conventional methods.
How EIS functions
EIS function is based on bipolar Measurements; 4 successive measurements are displayed with low frequency (1 KHz and then 700 Hz) ,very low frequency (1Hz) and then DC current are applied between six tactile electrodes placed symmetrically on the forehead, hands, and feet of the subject.
Each electrode is alternatively cathode and anode (bipolar mode), which permits the recording of the resistance using the Law of Ohm of 22 segments from the human body (Fig. 1).
Each segment is measuring in 1 second 32 times and for the 4 different currents, Therefore, the total of data are 2816 pulses per measurement.. Measured resistance(s) are transmitted with a numeric form to an informative program.
File:EIS Fig 1.JPG
Fig. 1
The resistance value R is converting to conductivity C, C = 1/R, incorporated in a graph. The graph of conductivity of the 22 segments (each segment value is the average of the 32 pulses) is called an Electro Scan Gram E.S.G.
File:EIS Fig 2.JPG
Fig.2
Normal range of ESG conductivity
The normal ranges of conductivity of the ESG graph (Fig. 3) were estimated with the statistical analysis raw data of healthy control groups of the pre-studies, clinical investigations and users’ databases.
File:EIS Fig 3.JPG
Fig.3
Background
The used technologies are:
1- Bio Impedance technologies in bipolar mode
2- Signal processing analysis in bipolar mode
3- Modeling process
1. Bio Impedance Technologies
• The Electrode Polarization Impedance (EPI) (article from book Nr 2)
• The electrical Bio Impedance Analysis (BIA)
• Bio Impedance Plethysmography (BIP) .
• The galvanic skin responses (GSR) .
The EPI (0.02-1Hz) is used for in vivo estimation of extracellular sodium concentration , and provides estimation of pump activity .
The BIA (700 Hz) is used for in vivo estimation of tissue PCo2 (article from book nr 3) and provides estimation of tissue hypoxia.
The BIP (1 KHz) is used for the estimation of the microcirculation blood flow

The GRS (DC) is used for the stress evaluation (article from book Nr 1) and provides estimation of sympathetic system activity.
2. EIS system Signal Processing Analysis:
Entire records of the EIS measurement (2816 pulses):
File:EIS Fig 4.JPG
Fig 4
The three steps of the EIS Signal Processing Analysis:
Step 1: ESG graph is converting to Second Derivative ESG (SDESG)
File:EIS Fig 5.JPG
Fig 5
The SDESG is a mathematical calculation to convert a graph with a scale 0-100 to a graph from +100 to -100.
The mathematical calculation of the standard deviation of the conductivity of the SDESG to the normal range provides the estimation of sympathetic system activity.
Step 2: Each 22 measured segments signal is analyzing (For the frequency of 700 Hz):
The stability of each segment signal (32 pulses) analysis provides the estimation of the tissue carbon dioxide (CO2) pressure and the microcirculation blood flow.
File:EIS Fig 6.JPG
Fig 6
Step 3: The Spectrum analysis and the Application of the Discrete Fourier Transform to the entire records (2816 pulses) provide 3 frequencies graphic where:
HF High frequencies, corresponding to the estimation of the pump activity.

LF Low frequencies, corresponding to the blood flow.

VLF Very Low frequencies, corresponding to the estimation of the tissue Oxygen available.

HF/VLF, ratio corresponding to the Oxygen uptake / Oxygen available ratio.

HF/LF, ratio corresponding to the pump activity / microcirculation blood flow ratio .
A red graphic indicates the Normal range of the 3 frequencies
File:EIS Fig 7.JPG
Fig. 7
3. Modelling Technology

What is modelling? Why a modelling?
At present, the treatment plans made by doctors rely on predictions based on statistical averages. The physiology of the human body is complex and individual, but advanced computational methods enable the modeling of the body.
Designing a reliable model requires accurate information about the functioning and anatomy of the body and about the properties of tissues. Advances in computing power enable utilization of quite complex models in the daily work of doctors.
As the possibilities of treating diseases improve, it is important to choose the right treatment for each individual patient.
Today, a doctor may be able to use a virtual model to test how the planned treatment would affect a patient, and can choose the best treatment method in each individual’s case.
EIS modelling process
The EIS modeling is based upon the resistance of the body systems related to the above physiologic parameters.
The EIS modeling process come from the Analysis of the ESG graph in domain analysis with the following steps:
step1- Scale conversion; EIS conversion from the scale 0-100 to -100/+100
step2- Venn diagram
step3- Maxwell equation
A first localization of organs by direct problems came out through application of the mathematical calculation of Venn diagram and application of the Maxwell equation for the value of intensity of the different zone of the human body modeling.
step 4- Color Code
The modeling of the EIS system is made according to a color code from blue to red related to the conductivity (from 0 to 110 10-6 S.m-1) of the zone.

Diagram of the process of EIS modeling
File:EIS diagram.JPG
----
Verification, Validation and Solving problems; 6 steps in 9 years
Citations
www.ldteck.com/1PDF/7.%20%20Bioimpedance_for_physicians_rev1.pdf
www.ldteck.com
www.csc.fi/english/csc/scientific_computing/applications/human_body
Citations
http://en. .org/wiki/Bioimpedance
http://en. .org/wiki/Fast_Fourier_transform
http://en. .org/wiki/Maxwell_equation
http://en. .org/wiki/Microcirculation
http://en. .org/wiki/NaKATPase
http://en. .org/wiki/Ohm_law
http://en. .org/wiki/Signal_processing
http://en. .org/wiki/Venn_Diagram

Main Menu

See Also

Main Menu