Estimating regions of air trapping from electrical impedance tomography data

Mueller, Jennifer L.; Muller, Peter A.; Mellenthin, Michelle M.; Murthy, R.; Capps, Michael; Alsaker, Melody; Deterding, Robin R.; Sagel, Scott D.; DeBoer, Emily M.

doi:10.1088/1361-6579/aac295

Cited by 25 publications

(27 citation statements)

References 40 publications

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“…The D-bar method has been used in some clinical studies. In [108], reconstructions by the Dbar method were used to compute ventilation-perfusion maps to identify regions of air trapping in two patients with cystic fibrosis, and the results were compared to computed tomography (CT) scans of the patients and to results from a healthy control. Global and regional EIT-derived spirometry measures were computed from D-bar reconstructions in [109] on 21 cystic fibrosis patients and 14 healthy controls, and the EIT measures demonstrated good correlation with spirometry and were able to distinguish between the cystic fibrosis patients and the healthy subjects.…”

Section: Discussion and Future Workmentioning

confidence: 99%

“…The regularization is accomplished via low-pass filtering in the scattering transform with a cutoff frequency dependent upon the noise level. The effect of domain-shape modeling and measurement errors on the 2-D D-bar method was analyzed in [107], and the method was used in the analysis of clinical data in [108,109].…”

Section: D-barmentioning

confidence: 99%

“…These findings may also be applicable to patients with other obstructive lung diseases. Mueller et al [108] used similar parameters to identify regions that are poorly ventilated but well perfused throughout the breathing and cardiac cycles. They compared these regions from two CF children to their chest CT and found that these regions were correlated to an air trapping area in CT images.…”

Section: Applications In Patients With Obstructive Lung Diseasesmentioning

confidence: 99%

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A review of electrical impedance tomography in lung applications: Theory and algorithms for absolute images

Martins

Sato

Moura

et al. 2019

Annual Reviews in Control

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Electrical Impedance Tomography (EIT) is under fast development, the present paper is a review of some procedures that are contributing to improve spatial resolution and material properties accuracy, admitivitty or impeditivity accuracy. A review of EIT medical applications is presented and they were classified into three broad categories: ARDS patients, obstructive lung diseases and perioperative patients. The use of absolute EIT image may enable the assessment of absolute lung volume, which may significantly improve the clinical acceptance of EIT. The Control Theory, the State Observers more specifically, have a developed theory that can be used for the design and operation of EIT devices. Electrode placement, current injection strategy and electrode electric potential measurements strategy should maximize the number of observable and controllable directions of the state vector space. A non-linear stochastic state observer, the Unscented Kalman Filter, is used directly for the reconstruction of absolute EIT images. Historically, difference images were explored first since they are more stable in the presence of modelling errors. Absolute images require more detailed models of contact impedance, stray capacitance and properly refined finite element mesh where the electric potential gradient is high. Parallelization of the forward *

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Section: Discussion and Future Workmentioning

confidence: 99%

Section: D-barmentioning

confidence: 99%

Section: Applications In Patients With Obstructive Lung Diseasesmentioning

confidence: 99%

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A review of electrical impedance tomography in lung applications: Theory and algorithms for absolute images

Martins

Sato

Moura

et al. 2019

Annual Reviews in Control

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“…The core patient population that might benefit from chest EIT are critically ill patients treated in neonatal (Chatziioannidis et al, 2013;Miedema et al, 2013;Rossi et al, 2013;Hough et al, 2014;van der Burg et al, 2016) and paediatric intensive care units (Steinmann et al, 2013;Wilsterman et al, 2016;Lupton-Smith et al, 2017). Children suffering from chronic lung diseases like cystic fibrosis or asthma (Lehmann et al, 2016;Mueller et al, 2018;Ngo et al, 2018;Vogt et al, 2018;Roethlisberger et al, 2018), especially those in the preschool age that cannot reliably perform conventional forced spirometric pulmonary function tests, represent another large patient group where EIT might become clinically relevant.…”

Section: Introductionmentioning

confidence: 99%

Chest electrical impedance tomography measures in neonatology and paediatrics—a survey on clinical usefulness

Frerichs¹,

Becher²

2019

Physiol. Meas.

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Objective: Chest electrical impedance tomography (EIT) is currently applied in neonatal and paediatric patients mainly within clinical studies. The findings of these studies imply that lung monitoring using EIT provides valuable information on regional lung ventilation and aeration at the bedside that might improve the therapy and care of this fragile patient population. In view of this postulated future use of EIT in neonatology and paediatrics we have conducted an international survey to assess the perceived usefulness of several measures derived from EIT examinations. Approach: A questionnaire validating the clinical usefulness of 14 previously described EIT measures was designed and sent to 36 clinicians with previous experience with EIT in neonatal and paediatric patients. A numerical rating scale was used to assess the usefulness of each measure. Main results: 34 clinicians from 12 countries responded to the invitation and 32 filled in the questionnaire. The mean clinical and EIT experience (SD) of the respondents was 19.49.1 yr and 7.75.8 yr, respectively. The top-rated measures were the global inhomogeneity index, silent spaces, change in end-expiratory lung impedance and ventrodorsal centre of ventilation. The bottom-rated were the regional respiratory time constant, tidal volume normalised to ml, respiratory rate and heart rate on the last rank. Significance: The survey revealed that EIT measures characterizing the ventilation and aeration distribution and the degree of their heterogeneity were deemed particularly useful. Respiratory rate, heart rate and overall tidal volume were considered less useful probably because these parameters are already routinely assessed by other conventional methods.

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“…Electrical impedance tomography (EIT) is a non-intrusive, radiation-free, and portable biomedical imaging modality. There are many medical applications of EIT in the context of thorax imaging, such as lung ventilation monitoring [61,14,19,17,48,49,40], lung perfusion imaging [38,18], detection or evaluation of pneumonia [27,45], and assessment of pulmonary edema [56]. In EIT measurement, an array of electrodes are attached around a human chest.…”

mentioning

confidence: 99%

Electrical impedance tomography with multiplicative regularization

Zhang¹,

Li²,

Yang³

et al. 2019

Inverse Problems &Amp; Imaging

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It is known that EIT inversion is an ill-posed problem, meaning that the solution is unstable if noise exists in the measured data. Generally, a regularization scheme is needed to alleviate the ill-posedness. In this work, a multiplicative regularization scheme is applied to EIT inversion. In this regularization scheme, a cost functional is constructed in which the data misfit functional is multiplied by a regularization factor, and no regularization parameter is needed. The regularization factor is based on the weighted L2-norm favoring 'blocky' profiles in the reconstructed images. Gauss-Newton method is used to minimize the cost functional iteratively. In the implementation of the multiplicative regularization scheme, the spatial gradient and divergence need to be computed on triangular meshes. For this purpose, the discrete exterior calculus (DEC) theory is applied to formulate the related discrete operators. Numerical and experimental results show good anti-noise performance of the multiplicative regularization scheme in EIT inverse problem.2010 Mathematics Subject Classification. Primary: 65N21.

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Estimating regions of air trapping from electrical impedance tomography data

Abstract: The results indicate the potential use of EIT-derived ventilation-perfusion index maps as a non-invasive method for identifying regions of air trapping.

Cited by 25 publications

References 40 publications

A review of electrical impedance tomography in lung applications: Theory and algorithms for absolute images

A review of electrical impedance tomography in lung applications: Theory and algorithms for absolute images

Chest electrical impedance tomography measures in neonatology and paediatrics—a survey on clinical usefulness

Electrical impedance tomography with multiplicative regularization

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