Human Electrical-Impedance-Tomography Reconstruction Models

Study Overview
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Brief Summary
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Current EIT analyses are based on the assumption of a circular thorax-shape and do not provide any information on lung borders. The aim is to obtain the body and lung border contours of male subjects by multi-detector computed tomography (MDCT) in defined thresholds of anthropometric data (gender = male; height; weight) for calibration of more realistic EIT reconstruction models.

Detailed Description
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A major drawback of EIT is its relatively poor spatial resolution and its limitation in measuring changes in bioimpedance as compared to a reference state (and not absolute quantities). Therefore, the technique cannot differentiate between extrapulmonary structures (muscles, thorax, heart, large vessels, spine, etc.) and non-aerated lung tissues - which is a major limitation for the clinical use of information derived from EIT-imaging. Moreover, current EIT-reconstruction algorithms are based on the consideration of a complete circular thoracic shape and do not take into account the body contours and lung borders. The investigators are convinced that EIT-derived dynamic bedside lung imaging can be advanced by morphing computed tomography (CT) scans of the respective thoracic levels with concomitant EIT images - thus enhancing EIT-image information with CT-data. Integrating the anatomy of thoracic shape and lung borders provided by high-spatial resolution multi detector CT-scans (MDCT) with high-temporal resolution EIT has the potential to improve image quality considerably. This data can be used to compute mean EIT-reconstruction models that further offer the possibility to develop novel and clinically meaningful EIT parameters. Therefore, the investigators hypothesize that by integration of CT-scan information of body and lung contours (and by computing different EIT reconstruction models) the current methodological limitations of EIT technology can be overcome.

Official Title
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Assessment of CT-derived Thoracic Electrical-Impedance-Tomography Finite Element Models

Conditions
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Respiratory Monitoring

Intervention / Treatment
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* Device: electrical impedance tomography


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: spontaneous breathing male subjects age > 18, clinical indication for thoracic CT scanning, matching of weight and height to the predefined model-thresholds Exclusion Criteria: pre-existing chronic pulmonary disease skin lesions / wounds in the thoracic plane where the EIT SensorBelt will be attached known allergy against any ingredient of the used ContactAgent abnormalities in thoracic shape as defined by the radiologist in charge (e.g. extreme kyphosis, funnel chest, pigeon breast, multiple rip fractures) pneumothorax pace maker (external and internal) other implanted electrical devices other methods measuring bioimpedance

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Study cohort 1<br>electrical impedance tomography | Device: electrical impedance tomography<br>* One continous electrical impedance tomography (EIT) measurement per subject of approximately 5 minutes duration (2 min prior to MDCT scanning, during end-inspiratory MDCT acquisition and 2 min after MDCT scanning)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Electrical Impedance Tomography Finite Element Model | Based on CT-derived thorax, lung and heart contours we propose to calculate human finite element models (FEM) for EIT analysis | approximately 1 year through study completion | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| height |  | at the time-point of inclusion | 
| weight |  | at the time-point of inclusion | 
| gender |  | at the time-point of inclusion | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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respiration, monitoring, physiologic, diagnostic techniques, respiratory system