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

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.

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.