Comparison of Computertomography Scan, Electrical Impedance Tomography, and Ultrasound of the Lung in Infants

Study Overview
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Brief Summary
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The study focuses on regional lung examination, in particular on the differentiation between collapsed and hyperinflated lung areas. The purpose of the study is to elaborate common and discriminative elements between different lung imaging modalities in infants and to generate hypotheses for the bedside use of EIT and LUS in infants.

Detailed Description
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Lung imaging has become increasingly important across medical specialties for diagnostic, monitoring, and investigative purposes in acute respiratory distress syndrome (ARDS). Lung computer tomography (CT) is the gold standard chest imaging technique to evaluate lung morphology and to perform a quantitative analysis of lung tissue aeration and recruitment. In the last decades, electrical impedance tomography (EIT) has gained a lot of attention in monitoring functional lung parameters. EIT is a non-invasive, bedside radiation-free functional imaging modality for continuous monitoring of lung ventilation and perfusion. Functional chest examinations with EIT are considered clinically relevant, especially for monitoring regional lung ventilation in patients with respiratory support, but also to assess aeration in preterm and term infants. In comparison with dynamic CT, EIT proved to be useful in bedside adjustments of mechanical ventilation with immediate feedback in adult patients. EIT lacks the spatial resolution of other imaging modalities but it is compact in size, uses no ionizing radiation, and gives functional images with high temporal resolution. As CT scans expose patients to ionizing radiation, there are no investigative studies comparing EIT with CT scans in newborns and infants. This would be useful, particularly, for correlating the reference impedance image with a CT scan to correctly calibrate anatomical structures and to differentiate between dependent and non-dependent lung areas. Likewise, lung ultrasound (LUS) has been increasingly used for the diagnosis of different lung conditions. Some validation studies compared LUS with CT scans and classified LUS to be a valid tool to assess regional and global lung aeration also in newborns. To our knowledge, there are no comparative studies between EIT and LUS in newborns and infants. The main objective is to compare different lung imaging modalities in infants with and without lung disease using the CT scan as reference method. The study focuses on regional lung examination. The purpose of the study is to elaborate common and discriminative elements between different lung imaging modalities in infants and to generate hypotheses for the bedside use of EIT and LUS in this group of patients. The CT scan is part of the routine care of the participants. No additional CT examinations will be performed for this study. LUS and EIT will be performed immediately before or after the planned CT scan. Both LUS and EIT measurements will be performed with mobile devices and will take approximately 20 minutes.

Official Title
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Comparison of Computertomography Scan, Electrical Impedance Tomography, and Ultrasound of the Lung in Infants - A Prospective Explorative Observational Study

Conditions
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Infant ALL, Computed Tomography, Electric Impedance, Ultrasonography, Lung Injury

Intervention / Treatment
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* Other: Electrical impedance tomography and ultrasonography of the lung


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients hospitalized at the Department of Pediatrics of the Medical University of Vienna who will get a CT scan of the thorax. Patients aged up to 12 months Exclusion Criteria: Unstable cardiovascular, respiratory and/or neurological conditions. Sternotomy during the previous 15 days. Thoracic skin lesions or wounds (including burns) on the thorax, where the EIT-electrode-belt would be placed.

Ages Eligible for Study
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Maximum Age: 12 Months

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Other: Electrical impedance tomography and ultrasonography of the lung|Both EIT and LUS are non-invasive methods and do not pose any additional risk for the patient. The LuMon System with pediatric EIT belts (LuMon Belt, Sentec, Landquart, Switzerland) will be used. The belt will be placed on the thorax circumference of the infant and connected to the LuMonConnector (Sentec, Landquart, Switzerland). Small electrical currents (3 mA, 198 kHz) will be repetitively injected in rotation through adjacent electrode pairs, and voltage changes will be measured by all passive electrodes pairs (scan rate 48 Hz). Changes in lung electrical impedance will be continuously recorded for 5 minutes. EIT data will be analyzed off-line using Matlab (Mathworks, Natick, Massachusetts, USA). The regional tidal volume distribution, the homogeneity of tidal ventilation distribution, regional respiratory system compliance, and alveolar overdistension and collapse will be assessed. LUS will be performed by experienced users, with a 10 MHz linear transducer.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Comparison between CT and EIT | Estimate difference of lung cross-section between CT scan and EIT | through study completion, an average of 1 year | 
| Comparison between CT and LUS | Comparison of diagnosis (presence of pathologic patterns including pneumothorax, emphysema, atelectasis, consolidation, ground glass opacity, bronchial wall thickening and/or dilatation) in CT and LUS | through study completion, an average of 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Comparison between EIT and LUS | Comparison of dynamic parameters of dorsal and ventral regions | through study completion, an average of 1 year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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CT, electrical impedance tomography, ultrasound