A parametric model of the relationship between EIT and total lung volume

Abstract

Spirometry and electrical impedance tomography (EIT) data from 26 healthy subjects (14 males, 12 females) were used to develop a model linking contrast variations in EIT difference images to lung volume changes. Eight recordings, each 64 s long, were made for each subject in four postures (standing, sitting, reclining at 45 degrees, supine) and two breathing modes (quiet tidal and deep breathing). Age, gender and five anthropometric variables were recorded. The database was divided into four subsets. The first subset, data from 22 subjects (12 males, 10 females) recorded in deep breathing mode, was used to create the model. Validation was done with the other subsets: data recorded during quiet tidal breathing in the same 22 subjects, and data recorded in both breathing modes for the other four subjects. A quadratic equation in DeltaV(P) (lung volume changes recorded by the spirometer) provided a very good fit to total contrast changes in the EIT images. The model coefficients were found to depend on posture, gender, thoracic circumference and scapular skin fold. To validate the model, the quadratic equation was inverted to estimate lung volume changes from the EIT images. The estimated changes were then compared to the measured volume changes. Validations with each data subset yielded mean standard errors ranging from 9.3% to 12.4%. The proposed model is a first step in enabling inter individual comparisons of EIT images since: (1) it provides a framework for incorporating the effects of anthropometric variables, gender and posture, and (2) it references the images to a physical quantity (volume) verifiable by spirometry.

Tomografia impedancyjna w diagnostyce i monitorowaniu zaburzeń funkcji płuc na oddziale intensywnej terapii — opis przypadku i przegląd piśmiennictwa

“…As EIT is non-invasive and virtually causes no adverse side effects (lack of radiation, no transport required), the method has become an attractive alternative to computed tomography, magnetic resonance imaging or ultrasound examinations. Many comparative medical trials have proved that the EIT results are reliable and repeatable [21][22][23][24][25][26][27][28][29].…”

Mental Health in Adults With Mild and Moderate Intellectual Disabilities

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“…[10,11] These deformation can be decomposed into independent conformal and not-conformal components. The electrodes themselves, though, are generally fabric or plastic backed and can not stretch to match the deformation exactly.…”