Abstract
A patient-friendly method for monitoring physiological and pathological processes in the human lung has not yet been established in clinical practice. The electrical impedance tomography seems to be a promising method for non invasive and easily applicable monitoring of the human lung, especially for ventilation monitoring.
In this thesis not only theoretical simulations of the electrical properties of lung tissue but also the analysis of real measurement data of healthy and edematic subjects were carried out.
A part of this work was the development of a semi-automatic system for generating finite element models of the human thorax out of computer tomographic or magnetic resonance images.
These models were used for simulating the electrical properties of biologic tissue. The results were used for generating artifical measurment data and an optimization of the number and position of electrodes and measurement frequencies.
By using real measurement data from healthy subjects and patients with severe lung edemamethod for direct parameter reconstruction was developed. With this method the results of the reconstruction were the parameters of the underlying tissue model by using a set of measurement data acquired at multiple frequencies.
Patients with lung edema were showing a massive fluid accumulation in the lower parts of the lung. This leads to an increase of tissue conductivity in this region. Based on this effectpromising approach for a simple edema index was introduced, which compares transimpedances derived from the upper and lower parts of the thorax.
As a reference for the data analysis computer tomography images from patients were used.
In this thesis not only theoretical simulations of the electrical properties of lung tissue but also the analysis of real measurement data of healthy and edematic subjects were carried out.
A part of this work was the development of a semi-automatic system for generating finite element models of the human thorax out of computer tomographic or magnetic resonance images.
These models were used for simulating the electrical properties of biologic tissue. The results were used for generating artifical measurment data and an optimization of the number and position of electrodes and measurement frequencies.
By using real measurement data from healthy subjects and patients with severe lung edemamethod for direct parameter reconstruction was developed. With this method the results of the reconstruction were the parameters of the underlying tissue model by using a set of measurement data acquired at multiple frequencies.
Patients with lung edema were showing a massive fluid accumulation in the lower parts of the lung. This leads to an increase of tissue conductivity in this region. Based on this effectpromising approach for a simple edema index was introduced, which compares transimpedances derived from the upper and lower parts of the thorax.
As a reference for the data analysis computer tomography images from patients were used.
| Translated title of the contribution | Evaluation of methods for determining extravascular lung water with electrical impedance tomography |
|---|---|
| Original language | German |
| Qualification | Doctor of Technology |
| Awarding Institution |
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| Supervisors/Advisors |
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| Publication status | Published - 3 Apr 2013 |
Keywords
- electrical impedance tomography
- extravascular lung water
- finite elements
- optimization
- image reconstruction
