Can We Measure Visceral Fat With Electrical Impedance Tomography (EIT) Now?
INTRO
Monitoring of visceral fat with electrical impedance tomography (EIT) non-invasive imaging method. Adipose tissue examination with electrical imaging impedance tomography (EIT).
Electrical impedance tomography
Electrical impedance tomography (EIT) is a new imaging technique. Based on the different electrical conductivities of different parts of the body. Many possible areas of application are still in the experimental stage. Their use has proven itself in checking lung function.
What is Electrical Impedance Tomography?
Electrical impedance tomography has already established itself in pulmonary function diagnostics. By means of electrodes, alternating electrical currents of different frequencies. And with low amplitude are fed into the neighboring tissue.
Electrical Non-invasive Imaging Impedance Tomography Method
As a new non-invasive imaging method for the examination of human tissue. Electrical impedance tomography (EIT) has already established itself in pulmonary function diagnostics. For other applications, the EIT is on the verge of a breakthrough.
By means of electrodes, alternating electrical currents of different frequencies. And with low amplitude are fed into the neighboring tissue. Depending on the nature or functional condition of the tissue, different conductivity results.
These depend on the respective impedance. Alternating current resistance of the corresponding body area. Several electrodes are positioned on the body surface to be measured.
Monitoring with electrical impedance tomography
Electrical impedance tomography (EIT) is a method for non-invasive. Radiation-free monitoring of regional lung function. It offers the great advantage that it can be carried out on the bedside in real time and is reproducible.
As a tomography method, it provides cross-sectional images of the lungs. Which show the spread of the tidal volume. Since electroimpedance tomography complements established radiological procedures and conventional lung monitoring.
It can be used for continuous visualization of lung function at the patient’s bedside. And to evaluate the effectiveness of therapeutic measures on regional ventilation distribution.
High-frequency electrical impedance tomography (EIT)
While high-frequency alternating currents with a small amplitude. Flow between each of the two electrodes. The electrical potential is measured at the other electrodes.
The measurement is constantly repeated by arbitrarily varying the stimulating electrode pair. The measured potentials result in a cross-sectional image. That allows conclusions to be drawn about the composition and condition of the tissue being examined.
Body tissue electrical examination impedance tomography (EIT)
In electrical impedance tomography, a distinction is made between absolute and functional EIT. In absolute EIT, the texture of the tissue is examined. While functional EIT measures different conductivities. Depending on the respective functional state of the body area to be measured.
Electrical impedance tomography (EIT) Function, Impact & Goals
As mentioned earlier, electrical impedance tomography is based on different conductivity. Of different areas of the body, biological tissues or organs. Thus, there are well-conductive and poorly-conductive areas of the body. In the human body, conductivity is determined by the number of free ions.
For example, water oak tissue with a high concentration of electrolytes. Can be expected to have better conductivity than adipose tissue. In addition, with functional changes in the organs. Chemical changes can also occur in the tissues that have an influence on conductivity.
Inaccurate electrical impedance tomography (EIT)
The absolute EIT is inaccurate. Because it depends on the individual anatomy and poorly conductive electrodes. This often leads to the formation of artifacts. Functional EIT can significantly reduce these errors by subtracting the representations.
The lungs are particularly suitable for examination using electrical impedance tomography. As they have a much lower conductivity than most other organs.
This results in an absolute contrast to the other parts of the body. Which has a positive effect on the representation in an imaging procedure. The conductivity of the lungs also changes cyclically. Depending on whether you are inhaling or exhaling.
Lungs electrical impedance tomography (EIT) examination
This is another reason to examine the lungs in particular using EIT. Their different conductivity during respiration suggests good results in checking lung function.
Advances in digital technology make it possible for intensive care physicians. To have the data obtained from the conductivity measurement of the lungs processed.
In such a way that lung function can be visualized directly at the patient’s bedside. On the basis of electrical impedance tomography. Pulmonary function monitors have recently been developed. Which are already used in intensive care medicine.
Mammography and electrical impedance tomography (EIT)
Studies are currently being carried out to open up other opportunities for the EIT. In the future, this technology can play a role as additional diagnostics in mammography.
It has been found that normal and malignant breast tissue. Have different conductivities at different frequencies. The same applies to additional diagnostics in gynecological cancer screening. Studies are also currently underway on the possible use of EIT in epilepsy and stroke.
A future application for intensive care monitoring of brain activity. In severe brain pathologies is also conceivable. The good electrical conductivity of the blood also implies a possible application. For the pictorial representation of organ blood flow.
Last but not least, electrical impedance tomography can also be used in sports medicine. To determine oxygen uptake (Vo2) or arterial blood pressure during exercise.
Electrical Impedance Tomography (EIT) Risks, Side Effects & Dangers
Compared to other tomography methods, electrical impedance tomography has the advantage. That it is completely harmless to the organism.
No ionizing radiation is used, as is the case with computed tomography. In addition, heating effects due to higher-frequency alternating currents. 10 to 100 kilohertz with low current can be avoided.
Since the equipment is also much cheaper. And smaller than with classical tomography methods. The EIT can thus be used with the patient over a longer period of time. And provide continuous real-time visualizations.
At present, however, the main disadvantage is the lower spatial resolution. Compared to other tomography methods. However, there are ideas to improve the resolution of the images. By increasing the number of electrodes. The quality of the images also still has shortcomings.
Electrical impedance tomography (EIT) quality
However, quality improvement is gradually taking place. Through the increasing use of active surface electrodes. Another disadvantage is that the current does not remain in the body section to be examined. But is distributed in three-dimensional space following the least resistance.
As a result, image creation is much more complicated. Than with classical computed tomography. Several two-dimensional representations in three-dimensional space are necessary. Finally, create a three-dimensional image. Which is then presented again two-dimensionally.
This results in the so-called “inverse problem”. The inverse problem states that the cause must be inferred from the present result. In most cases, these problems are very difficult or impossible to solve.
Only in combination with other procedures can the cause be clarified. Further studies still need to provide sufficient experience to evaluate the EIT’s representations.
What are the clinical benefits of electrical impedance tomography?
The main limitations of previous EIT systems were the poor measurement sensitivity. And the high susceptibility to signal interference. From other devices used in the clinical environment.
Acceptable lung tomograms and ventilation images could only be generated during breathing maneuvers. With maximum inspiration and expiration. Which was not practicable for intensive care patients.
The images did not provide reliable information about the patient’s respiratory condition. During the development of EIT. The research interest was mainly focused on expanding the technology. Towards multi-frequency systems.
For the special acquisition of information on tissue properties. The introduction of new image reconstruction algorithms and 3D imaging. The less spectacular. But nevertheless indispensable. Goal of improving signal acquisition quality was not the focus of the activities.
Why is electrical impedance tomography (EIT) being introduced?
As an additional imaging technique in medicine. In today’s world, doctors are accustomed to the rapid development. In the field of high-resolution imaging techniques. Such as 128-slice CT scanners, f-MRI, SPECT or 3D ultrasound. So do we need EIT, with its limited local resolution, as another tool?
In principle, it can be said that, on the one hand. EIT provides images based on novel information. E.g. on electrical tissue properties. On the other hand, electrical impedance tomography can be used as a continuous bedside monitoring procedure. As it requires only small devices.
In addition, patients or operating personnel are not exposed to ionizing radiation. These opportunities give rise to the search for areas of application. Where the EIT contributes to improving patient care.
What information does electrical impedance tomography provide?
EIT was introduced by Barber and Brown in the early 1980s. A short time later, a wide range of possible clinical applications were proposed. From gastric emptying to monitor brain function, to breast imaging, to the evaluation of lung function.
Arguably, the greatest medical benefit of EIT. Lies in the area of monitoring regional lung function in intensive care patients. To date, the heterogeneous distribution of lung damage. E.g. in ARDS patients (acute respiratory distress syndrome). Can only be detected outside intensive care units. By CT or by non-localizing procedures. Such as MIGET (multiple inert gas elimination technique).
EIT is the only method that can directly demonstrate whether closed lung regions can be opened by a recruitment maneuver. And kept open by optimized ventilation settings. To minimize the risk of VALI (ventilator-associated lung injury).
CONTENT:
- Electrical impedance tomography
- What is Electrical Impedance Tomography?
- Electrical Non-invasive Imaging Impedance Tomography Method
- Monitoring with electrical impedance tomography
- High-frequency electrical impedance tomography (EIT)
- Body tissue electrical examination impedance tomography (EIT)
- Electrical impedance tomography (EIT) Function, Impact & Goals
- Inaccurate electrical impedance tomography (EIT)
- Lungs electrical impedance tomography (EIT) examination
- Mammography and electrical impedance tomography (EIT)
- Electrical Impedance Tomography (EIT) Risks, Side Effects & Dangers
- Electrical impedance tomography (EIT) quality
- What are the clinical benefits of electrical impedance tomography?
- Why is electrical impedance tomography (EIT) an additional imaging technique in medicine?
- What information does electrical impedance tomography provide?