Feasibility of using ‘lung density’ values estimated from EIT images for clinical diagnosis of lung abnormalities in mechanically ventilated ICU patients

Abstract

This paper reports on the results of a study which compares lung density values obtained from electrical impedance tomography (EIT), clinical diagnosis and CT values (HU) within a region of interest in the lung. The purpose was to assess the clinical use of lung density estimation using EIT data. In 11 patients supported by a mechanical ventilator, the consistency of regional lung density measurements as estimated by EIT was validated to assess the feasibility of its use in intensive care medicine. There were significant differences in regional lung densities recorded in the supine position between normal lungs and diseased lungs associated with pneumonia, atelectasis and pleural effusion (normal; 240 ± 71.7 kg m(-3), pneumonia; 306 ± 38.6 kg m(-3), atelectasis; 497 ± 130 kg m(-3), pleural effusion; 467 ± 113 kg m(-3): Steel-Dwass test, p < 0.05). In addition, in order to compare lung density with CT image pixels, the image resolution of CT images, which was originally 512 × 512 pixels, was changed to 16 × 16 pixels to match that of the EIT images. The results of CT and EIT images from five patients in an intensive care unit showed a correlation coefficient of 0.66 ± 0.13 between the CT values (HU) and the lung density values (kg m(-3)) obtained from EIT. These results indicate that it may be possible to obtain a quantitative value for regional lung density using EIT.

Análise de perfil epidemiológico e parâmetros ventilatórios de puérperas submetidas à ventilação mecânica por meio da tomografia por impedância elétrica

“…Nebuya et al 25 applied a different look aimed at regional pulmonary quantification when assessing the clinical use of pulmonary density estimation using EIT data. The study had 11 patients on mechanical ventilation, with significant differences in regional pulmonary densities recorded in the supine position, between normal lungs and patients associated with pneumonia, atelectasis and pleural effusion.…”

Torso shape detection to improve lung monitoring

“…The cross-section of a subject body has been often simplified as a circular shape (Zhang et al 2012). In the most accurate cases, the torso boundary shape was segmented from a CT scan (Chen et al 2011, Nebuya et al 2015, which was performed by clinicians for other purposes. However, whenever such contour is assumed to be the same for a range of patients a shape mismatch is included in the analysis, introducing artefacts.…”

An innovative design for cardiopulmonary resuscitation manikins based on a human-like thorax and embedded flow sensors

“…fibreglass-coated ribs), increasing the thickness of the rib cage and/or using a foam of higher density for lungs. Developing a thicker rib cage was restricted by our manufacturing constraints (Speedy 300 laser engraver) while higher density foams mimicking the density of lung tissue 25 are unavailable. The energy transmitted into the manikin (the work ( W )) can be increased by enhancing the damping coefficient of the thorax which can be facilitated by connecting the lungs to the rib cage, that is, mimicking the pleural cavity and implementing flow restrictions.…”