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Byrne DP, Keeshan B, Hosgood G, Adler A, Mosing M. Comparison of electrical impedance tomography and spirometry-based measures of airflow in healthy adult horses. Front Physiol 2023; 14:1164646. [PMID: 37476683 PMCID: PMC10354512 DOI: 10.3389/fphys.2023.1164646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 06/26/2023] [Indexed: 07/22/2023] Open
Abstract
Electrical impedance tomography (EIT) is a non-invasive diagnostic tool for evaluating lung function. The objective of this study was to compare respiratory flow variables calculated from thoracic EIT measurements with corresponding spirometry variables. Ten healthy research horses were sedated and instrumented with spirometry via facemask and a single-plane EIT electrode belt around the thorax. Horses were exposed to sequentially increasing volumes of apparatus dead space between 1,000 and 8,500 mL, in 5-7 steps, to induce carbon dioxide rebreathing, until clinical hyperpnea or a tidal volume of 150% baseline was reached. A 2-min stabilization period followed by 2 minutes of data collection occurred at each timepoint. Peak inspiratory and expiratory flow, inspiratory and expiratory time, and expiratory nadir flow, defined as the lowest expiratory flow between the deceleration of flow of the first passive phase of expiration and the acceleration of flow of the second active phase of expiration were evaluated with EIT and spirometry. Breathing pattern was assessed based on the total impedance curve. Bland-Altman analysis was used to evaluate the agreement where perfect agreement was indicated by a ratio of EIT:spirometry of 1.0. The mean ratio (bias; expressed as a percentage difference from perfect agreement) and the 95% confidence interval of the bias are reported. There was good agreement between EIT-derived and spirometry-derived peak inspiratory [-15% (-46-32)] and expiratory [10% (-32-20)] flows and inspiratory [-6% (-25-18)] and expiratory [5% (-9-20)] times. Agreement for nadir flows was poor [-22% (-87-369)]. Sedated horses intermittently exhibited Cheyne-Stokes variant respiration, and a breath pattern with incomplete expiration in between breaths (crown-like breaths). Electrical impedance tomography can quantify airflow changes over increasing tidal volumes and changing breathing pattern when compared with spirometry in standing sedated horses.
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Affiliation(s)
- David P. Byrne
- School of Veterinary Medicine, Murdoch University, Perth, WA, Australia
| | - Ben Keeshan
- Department of Systems and Computer Engineering, Carleton University, Ottawa, ON, Canada
| | - Giselle Hosgood
- School of Veterinary Medicine, Murdoch University, Perth, WA, Australia
| | - Andy Adler
- Department of Systems and Computer Engineering, Carleton University, Ottawa, ON, Canada
| | - Martina Mosing
- Anaesthesiology and Perioperative Intensive Care, Department for Companion Animals and Horses, University of Veterinary Medicine, Vienna, Austria
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Pensabene M, Gambazza S, Carta F, Rocchi A, Lelii M, Madini B, Hassan V, Piotto M, Patria MF. Using electrical impedance tomography to characterize lung impairment of children with primary ciliary dyskinesia: A pilot cross-sectional study. Pediatr Pulmonol 2023; 58:1051-1058. [PMID: 36571235 DOI: 10.1002/ppul.26293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 11/02/2022] [Accepted: 12/18/2022] [Indexed: 12/27/2022]
Abstract
BACKGROUND In children with primary ciliary dyskinesia (PCD), measures more sensitive than spirometry are needed to characterize underlying pulmonary impairment. Electrical impedance tomography (EIT) is a promising noninvasive method for monitoring the distribution of lung ventilation, and it does not require patient collaboration. We aimed to provide an assessment of the feasibility and clinical usefulness of EIT in characterizing lung impairment in children with PCD, compared to spirometry and multiple breath nitrogen washout (MBWN2 ) test. METHODS Children and adolescents with PCD underwent MBWN2 test as first respiratory assessment, followed by EIT monitoring and spirometry during outpatient follow-up. RESULTS We included 12 out of 16 individuals regularly followed at our clinic. A total of 41.7% (5/12) showed abnormal forced expiratory volume in 1 s (FEV1 ), whereas 11/12 (91.7%) had abnormal ventilation inhomogeneity measured with MBWN2 test. Using EIT, the global inhomogeneity (GITOT ) index showed moderate to strong correlation with FEV1 (ρ = -0.55, 95% confidence interval [CI]: -0.87 to 0.02) and ranged from 37 to 44, with the highest inhomogeneity detected in the dorsal right quadrant. GITOT was moderately correlated with RV/TLC %predicted (ρ = 0.38, 95% CI: -0.17 to 0.74), while we detected a weak correlation between GITOT and lung clearance index (ρ = 0.29, 95% CI: -0.45 to 0.82). CONCLUSION EIT appears promising as a noninvasive technique to characterize ventilation distribution in children with PCD, thus providing a complementary assessment to static and dynamic lung function measures of PCD disease.
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Affiliation(s)
- Mariacarola Pensabene
- Pediatric Highly Intensive Care Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Simone Gambazza
- Healthcare Professions Department, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Federica Carta
- Healthcare Professions Department, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Alessia Rocchi
- Pediatric Emergency Department, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Mara Lelii
- Pediatric Highly Intensive Care Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Barbara Madini
- Pediatric Highly Intensive Care Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Vittoria Hassan
- Pediatric Emergency Department, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Marta Piotto
- Pediatric Emergency Department, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Maria Francesca Patria
- Pediatric Highly Intensive Care Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
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Rein A, Ngo C, van den Berg M, Böll S, Lassay L, Kontny U, Wagner N, Leonhardt S, Tenbrock K, Verjans E. Evaluation of lung function in a German single center cohort of young patients with sickle cell disease using EIT and standard techniques. Front Med (Lausanne) 2023; 10:1100180. [PMID: 36993804 PMCID: PMC10040809 DOI: 10.3389/fmed.2023.1100180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 02/21/2023] [Indexed: 03/15/2023] Open
Abstract
Background and objectiveSickle cell disease (SCD) is a very common autosomal recessive hemoglobinopathy leading to multiple pulmonary complications that are closely associated with mortality. The pathophysiology of chronic pulmonary involvement is not yet fully understood and no specific therapies are available.MethodsThe aim of this cross-sectional study was to characterize the lung function of children and young adolescents with SCD in a German single-center cohort and to extend conventional lung function testing by the use of a new imaging method. We performed spirometry and body plethysmography in 35 children and young adults with hemoglobin SS, SC, S/β-thalassemia as well as 50 controls. These data were compared with clinical characteristics and typical laboratory parameters of hemolysis and disease activity in SCD. To identify lung inhomogeneities, for example due to atelectasis, hyperinflation, air trapping or vascular occlusions, we used the promising new method of electrical impedance tomography (EIT) and calculated global inhomogeneity indices.ResultsLung function of patients with SCD was significantly reduced compared to that of healthy controls. When the result was found to be pathological, the most commonly observed type of breathing disorder was classified as restrictive. Laboratory parameters showed typical features of SCD including decreased levels of hemoglobin and hematocrit and elevated levels of leucocytes, platelets, lactate dehydrogenase and total bilirubin. However, there was no correlation between blood values and reduced lung function. Electrical impedance tomography (EIT) revealed no abnormalities in SCD patients compared to healthy controls. In particular, we were unable to demonstrate any regional inhomogeneities in lung ventilation.ConclusionIn our study, SCD patients showed impaired lung function, with a relevant percentage of patients suffering from restrictive breathing disorder. Signs of obstruction could not be detected. Electrical impedance tomography (EIT) measurements revealed no unevenness that would suggest air entrapment, blockage of blood vessels, excessive inflation, obstruction, or other forms of lung disease. Additionally, the reduction in lung function observed in SCD patients was not related to the disease severity or laboratory test results.
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Affiliation(s)
- Alina Rein
- Department of Pediatrics, Medical Faculty, RWTH Aachen University, University Hospital Aachen, Aachen, Germany
| | - Chuong Ngo
- Medical Information Technology, Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany
| | - Maike van den Berg
- Medical Information Technology, Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany
| | - Svenja Böll
- Department of Pediatrics, Medical Faculty, RWTH Aachen University, University Hospital Aachen, Aachen, Germany
| | - Lisa Lassay
- Department of Pediatrics, Medical Faculty, RWTH Aachen University, University Hospital Aachen, Aachen, Germany
| | - Udo Kontny
- Department of Pediatrics, Medical Faculty, RWTH Aachen University, University Hospital Aachen, Aachen, Germany
| | - Norbert Wagner
- Department of Pediatrics, Medical Faculty, RWTH Aachen University, University Hospital Aachen, Aachen, Germany
| | - Steffen Leonhardt
- Medical Information Technology, Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany
| | - Klaus Tenbrock
- Department of Pediatrics, Medical Faculty, RWTH Aachen University, University Hospital Aachen, Aachen, Germany
| | - Eva Verjans
- Department of Pediatrics, Medical Faculty, RWTH Aachen University, University Hospital Aachen, Aachen, Germany
- *Correspondence: Eva Verjans,
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Frerichs I, Lasarow L, Strodthoff C, Vogt B, Zhao Z, Weiler N. Spatial Ventilation Inhomogeneity Determined by Electrical Impedance Tomography in Patients With Chronic Obstructive Lung Disease. Front Physiol 2021; 12:762791. [PMID: 34966289 PMCID: PMC8712108 DOI: 10.3389/fphys.2021.762791] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Accepted: 11/16/2021] [Indexed: 11/13/2022] Open
Abstract
The aim of this study was to examine whether electrical impedance tomography (EIT) could determine the presence of ventilation inhomogeneity in patients with chronic obstructive lung disease (COPD) from measurements carried out not only during conventional forced full expiration maneuvers but also from forced inspiration maneuvers and quiet tidal breathing and whether the inhomogeneity levels were comparable among the phases and higher than in healthy subjects. EIT data were acquired in 52 patients with exacerbated COPD (11 women, 41 men, 68 ± 11 years) and 14 healthy subjects (6 women, 8 men, 38 ± 8 years). Regional lung function parameters of forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), forced inspiratory vital capacity (FIVC), forced inspiratory volume in 1 s (FIV1), and tidal volume (V T ) were determined in 912 image pixels. The spatial inhomogeneity of the pixel parameters was characterized by the coefficients of variation (CV) and the global inhomogeneity (GI) index. CV and GI values of pixel FVC, FEV1, FIVC, FIV1, and VT were significantly higher in patients than in healthy subjects (p ≤ 0.0001). The ventilation distribution was affected by the analyzed lung function parameter in patients (CV: p = 0.0024, GI: p = 0.006) but not in healthy subjects. Receiver operating characteristic curves showed that CV and GI discriminated patients from healthy subjects with an area under the curve (AUC) of 0.835 and 0.852 (FVC), 0.845 and 0.867 (FEV1), 0.903 and 0.903 (FIVC), 0.891 and 0.882 (FIV1), and 0.821 and 0.843 (VT), respectively. These findings confirm the ability of EIT to identify increased ventilation inhomogeneity in patients with COPD.
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Affiliation(s)
- Inéz Frerichs
- Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Kiel, Germany
| | - Livia Lasarow
- Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Kiel, Germany
| | - Claas Strodthoff
- Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Kiel, Germany
| | - Barbara Vogt
- Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Kiel, Germany
| | - Zhanqi Zhao
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China.,Institute of Technical Medicine, Furtwangen University, Villingen-Schwenningen, Germany
| | - Norbert Weiler
- Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Kiel, Germany
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Haris K, Vogt B, Strodthoff C, Pessoa D, Cheimariotis GA, Rocha B, Petmezas G, Weiler N, Paiva RP, de Carvalho P, Maglaveras N, Frerichs I. Identification and analysis of stable breathing periods in electrical impedance tomography recordings. Physiol Meas 2021; 42. [PMID: 34098533 DOI: 10.1088/1361-6579/ac08e5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 06/07/2021] [Indexed: 11/11/2022]
Abstract
Objective. In this paper, an automated stable tidal breathing period (STBP) identification method based on processing electrical impedance tomography (EIT) waveforms is proposed and the possibility of detecting and identifying such periods using EIT waveforms is analyzed. In wearable chest EIT, patients breathe spontaneously, and therefore, their breathing pattern might not be stable. Since most of the EIT feature extraction methods are applied to STBPs, this renders their automatic identification of central importance.Approach. The EIT frame sequence is reconstructed from the raw EIT recordings and the raw global impedance waveform (GIW) is computed. Next, the respiratory component of the raw GIW is extracted and processed for the automatic respiratory cycle (breath) extraction and their subsequent grouping into STBPs.Main results. We suggest three criteria for the identification of STBPs, namely, the coefficient of variation of (i) breath tidal volume, (ii) breath duration and (iii) end-expiratory impedance. The total number of true STBPs identified by the proposed method was 294 out of 318 identified by the expert corresponding to accuracy over 90%. Specific activities such as speaking, eating and arm elevation are identified as sources of false positives and their discrimination is discussed.Significance. Simple and computationally efficient STBP detection and identification is a highly desirable component in the EIT processing pipeline. Our study implies that it is feasible, however, the determination of its limits is necessary in order to consider the implementation of more advanced and computationally demanding approaches such as deep learning and fusion with data from other wearable sensors such as accelerometers and microphones.
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Affiliation(s)
- K Haris
- Lab of Computing, Medical Informatics and Biomedical Imaging Technologies, Aristotle University, Thessaloniki, Greece.,Department of Informatics and Computer Engineering, University of West Attica, Greece
| | - B Vogt
- Department of Anaesthesiology and Intensive Care Medicine, University Medical Centre Schleswig-Holstein, Campus Kiel, Germany
| | - C Strodthoff
- Department of Anaesthesiology and Intensive Care Medicine, University Medical Centre Schleswig-Holstein, Campus Kiel, Germany
| | - D Pessoa
- University of Coimbra, Centre for Informatics and Systems of the University of Coimbra, Department of Informatics Engineering, 3030-290 Coimbra, Portugal
| | - G-A Cheimariotis
- Lab of Computing, Medical Informatics and Biomedical Imaging Technologies, Aristotle University, Thessaloniki, Greece
| | - B Rocha
- University of Coimbra, Centre for Informatics and Systems of the University of Coimbra, Department of Informatics Engineering, 3030-290 Coimbra, Portugal
| | - G Petmezas
- Lab of Computing, Medical Informatics and Biomedical Imaging Technologies, Aristotle University, Thessaloniki, Greece
| | - N Weiler
- Department of Anaesthesiology and Intensive Care Medicine, University Medical Centre Schleswig-Holstein, Campus Kiel, Germany
| | - R P Paiva
- University of Coimbra, Centre for Informatics and Systems of the University of Coimbra, Department of Informatics Engineering, 3030-290 Coimbra, Portugal
| | - P de Carvalho
- University of Coimbra, Centre for Informatics and Systems of the University of Coimbra, Department of Informatics Engineering, 3030-290 Coimbra, Portugal
| | - N Maglaveras
- Lab of Computing, Medical Informatics and Biomedical Imaging Technologies, Aristotle University, Thessaloniki, Greece.,Department of Electrical and Computer Engineering, Northwestern University, Evanston, IL, United States of America
| | - I Frerichs
- Department of Anaesthesiology and Intensive Care Medicine, University Medical Centre Schleswig-Holstein, Campus Kiel, Germany
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Sang L, Zhao Z, Lin Z, Liu X, Zhong N, Li Y. A narrative review of electrical impedance tomography in lung diseases with flow limitation and hyperinflation: methodologies and applications. ANNALS OF TRANSLATIONAL MEDICINE 2020; 8:1688. [PMID: 33490200 PMCID: PMC7812189 DOI: 10.21037/atm-20-4984] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Electrical impedance tomography (EIT) is a functional radiation-free imaging technique that measures regional lung ventilation distribution by calculating the impedance changes in the corresponding regions. The aim of the present review was to summarize the current literature concerning the methodologies and applications of EIT in lung diseases with flow limitation and hyperinflation. PubMed was searched up to May 2020 to identify studies investigating the use of EIT in patients with asthma, bronchiectasis, bronchitis, bronchiolitis, chronic obstructive pulmonary disease, and cystic fibrosis. The extracted data included study design, EIT methodologies, interventions, validation and comparators, population characteristics, and key findings. Of the 44 included studies, seven were related to simulation, animal experimentation, or reconstruction algorithm development with evaluation on patients; 27 studies had the primary objective of validating EIT technique and measures including regional ventilation distribution, regional EIT-spirometry parameters, end-expiratory lung impedance, and regional time constants; and 10 studies had the primary objective of applying EIT to monitor the response to therapeutic interventions, including various ventilation supports, patient repositioning, and airway suctioning. In pediatric and adult patients, EIT has been successfully validated for assessing spatial and temporal ventilation distribution, measuring changes in lung volume and flow, and studying regional respiratory mechanics. EIT has also demonstrated potential as an alternative or supplement to well-established measurement modalities (e.g., conventional pulmonary function testing) to monitor the progression of obstructive lung diseases, although the existing literature lacks prediction values as references and lacks clinical outcome evidence.
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Affiliation(s)
- Ling Sang
- State Key Laboratory of Respiratory Diseases, Guangzhou Institute of Respiratory Health, Guangzhou Medical University, the First Affiliated Hospital of Guangzhou Medical University, Department of Crit Care Med, Guangzhou, China
| | - Zhanqi Zhao
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China.,Institute of Technical Medicine, Furtwangen University, Villingen-Schwenningen, Germany
| | - Zhimin Lin
- State Key Laboratory of Respiratory Diseases, Guangzhou Institute of Respiratory Health, Guangzhou Medical University, the First Affiliated Hospital of Guangzhou Medical University, Department of Crit Care Med, Guangzhou, China
| | - Xiaoqing Liu
- State Key Laboratory of Respiratory Diseases, Guangzhou Institute of Respiratory Health, Guangzhou Medical University, the First Affiliated Hospital of Guangzhou Medical University, Department of Crit Care Med, Guangzhou, China
| | - Nanshan Zhong
- State Key Laboratory of Respiratory Diseases, Guangzhou Institute of Respiratory Health, Guangzhou Medical University, the First Affiliated Hospital of Guangzhou Medical University, Department of Crit Care Med, Guangzhou, China
| | - Yimin Li
- State Key Laboratory of Respiratory Diseases, Guangzhou Institute of Respiratory Health, Guangzhou Medical University, the First Affiliated Hospital of Guangzhou Medical University, Department of Crit Care Med, Guangzhou, China
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7
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Singh N, Kumar P, Riaz U. Applications of near infrared and surface enhanced Raman scattering techniques in tumor imaging: A short review. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 222:117279. [PMID: 31234091 DOI: 10.1016/j.saa.2019.117279] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 06/08/2019] [Accepted: 06/15/2019] [Indexed: 06/09/2023]
Abstract
Imaging technologies play a vital role in clinical oncology and have undergone massive growth over the past few decades. Research in the field of tumor imaging and biomedical diagnostics requires early detection of physiological alterations so as to provide curative treatment in real time. The objective of this review is to provide an insight about near infrared fluorescence (NIRF) and surface enhanced Raman scattering (SERS) imaging techniques that can be used to expand their capabilities for the early detection and diagnosis of cancer cells. Basic setup, principle and working of the instruments has been provided and common NIRF imaging agents as well as SERS tags are also discussed besides the analytical advantages/disadvantages of these techniques. This review can help researchers working in the field of molecular imaging to design cost effective fluorophores and SERS tags to overcome the limitations of both NIRF as well as SERS imaging technologies.
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Affiliation(s)
- Neetika Singh
- Materials Research Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025, India; Advanced Instrumentation Research Facility, Jawaharlal Nehru University, New Delhi 110067, India
| | - Prabhat Kumar
- Materials Research Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025, India; Advanced Instrumentation Research Facility, Jawaharlal Nehru University, New Delhi 110067, India
| | - Ufana Riaz
- Materials Research Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025, India; Advanced Instrumentation Research Facility, Jawaharlal Nehru University, New Delhi 110067, India.
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Vogt B, Deuß K, Hennig V, Zhao Z, Lautenschläger I, Weiler N, Frerichs I. Regional lung function in nonsmokers and asymptomatic current and former smokers. ERJ Open Res 2019; 5:00240-2018. [PMID: 31321224 PMCID: PMC6628636 DOI: 10.1183/23120541.00240-2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 05/01/2019] [Indexed: 11/05/2022] Open
Abstract
Electrical impedance tomography (EIT) is able to detect rapid lung volume changes during breathing. The aim of our observational study was to characterise the heterogeneity of regional ventilation distribution in lung-healthy adults by EIT and to detect the possible impact of tobacco consumption. A total of 219 nonsmokers, asymptomatic ex-smokers and current smokers were examined during forced full expiration using EIT. Forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC were determined in 836 EIT image pixels for the analysis of spatial and temporal ventilation distribution. Coefficients of variation (CVs) of these pixel values were calculated. Histograms and medians of FEV1/FVCEIT and times required to exhale 50%, 75%, 90% of FVCEIT (t50, t75 and t90) were generated. CV of FEV1/FVCEIT distinguished among all groups (mean±sd: nonsmokers 0.43±0.05, ex-smokers 0.52±0.09, smokers 0.62±0.16). Histograms of FEV1/FVCEIT differentiated between nonsmokers and the other groups (p<0.0001). Medians of t50, t75 and t90 showed the lowest values in nonsmokers. Median t90 separated all groups (median (interquartile range): nonsmokers 0.82 (0.67-1.15), ex-smokers 1.41 (1.03-2.21), smokers 1.91 (1.33-3.53)). EIT detects regional ventilation heterogeneity during forced expiration in healthy nonsmokers and its increase in asymptomatic former and current smokers. Therefore, EIT-derived reference values should only be collected from nonsmoking lung-healthy adults.
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Affiliation(s)
- Barbara Vogt
- Dept of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Kathinka Deuß
- Dept of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Victoria Hennig
- Dept of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Zhanqi Zhao
- Dept of Biomedical Engineering, Fourth Military Medical University, Xi'an, China.,Dept of Biomedical Engineering, Furtwangen University, Villingen-Schwenningen, Germany
| | - Ingmar Lautenschläger
- Dept of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Norbert Weiler
- Dept of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Inéz Frerichs
- Dept of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
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9
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Frerichs I, Becher T. Chest electrical impedance tomography measures in neonatology and paediatrics—a survey on clinical usefulness. Physiol Meas 2019; 40:054001. [DOI: 10.1088/1361-6579/ab1946] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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10
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Ngo C, Spagnesi S, Munoz C, Lehmann S, Vollmer T, Misgeld B, Leonhardt S. Assessing regional lung mechanics by combining electrical impedance tomography and forced oscillation technique. ACTA ACUST UNITED AC 2019; 63:673-681. [PMID: 28850542 DOI: 10.1515/bmt-2016-0196] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 07/17/2017] [Indexed: 11/15/2022]
Abstract
There is a lack of noninvasive pulmonary function tests which can assess regional information of the lungs. Electrical impedance tomography (EIT) is a radiation-free, non-invasive real-time imaging that provides regional information of ventilation volume regarding the measurement of electrical impedance distribution. Forced oscillation technique (FOT) is a pulmonary function test which is based on the measurement of respiratory mechanical impedance over a frequency range. In this article, we introduce a new measurement approach by combining FOT and EIT, named the oscillatory electrical impedance tomography (oEIT). Our oEIT measurement system consists of a valve-based FOT device, an EIT device, pressure and flow sensors, and a computer fusing the data streams. Measurements were performed on five healthy volunteers at the frequencies 3, 4, 5, 6, 7, 8, 10, 15, and 20 Hz. The measurements suggest that the combination of FOT and EIT is a promising approach. High frequency responses are visible in the derivative of the global impedance index ΔZeit(t,fos). $\Delta {Z_{{\text{eit}}}}(t,{f_{{\text{os}}}}).$ The oEIT signals consist of three main components: forced oscillation, spontaneous breathing, and heart activity. The amplitude of the oscillation component decreases with increasing frequency. The band-pass filtered oEIT signal might be a new tool in regional lung function diagnostics, since local responses to high frequency perturbation could be distinguished between different lung regions.
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Affiliation(s)
- Chuong Ngo
- Philips Chair of Medical Information Technology, Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Pauwelsstr. 20, 52074 Aachen, Germany
| | - Sarah Spagnesi
- Philips Chair of Medical Information Technology, Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Pauwelsstr. 20, 52074 Aachen, Germany
| | - Carlos Munoz
- Philips Chair of Medical Information Technology, Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Pauwelsstr. 20, 52074 Aachen, Germany
| | - Sylvia Lehmann
- Department of Pediatric Pulmonology, University Hospital RWTH Aachen, Pauwelsstr. 30, 52074 Aachen, Germany
| | - Thomas Vollmer
- Philips GmbH Innovative Technologies Aachen, Pauwelsstr. 17, 52074 Aachen, Germany
| | - Berno Misgeld
- Philips Chair of Medical Information Technology, Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Pauwelsstr. 20, 52074 Aachen, Germany
| | - Steffen Leonhardt
- Philips Chair of Medical Information Technology, Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Pauwelsstr. 20, 52074 Aachen, Germany
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Rapin M, Braun F, Adler A, Wacker J, Frerichs I, Vogt B, Chetelat O. Wearable Sensors for Frequency-Multiplexed EIT and Multilead ECG Data Acquisition. IEEE Trans Biomed Eng 2019; 66:810-820. [DOI: 10.1109/tbme.2018.2857199] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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12
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Zhang C, Dai M, Liu W, Bai X, Wu J, Xu C, Xia J, Fu F, Shi X, Dong X, Jin F, You F. Global and regional degree of obstruction determined by electrical impedance tomography in patients with obstructive ventilatory defect. PLoS One 2018; 13:e0209473. [PMID: 30571739 PMCID: PMC6301672 DOI: 10.1371/journal.pone.0209473] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 12/06/2018] [Indexed: 11/19/2022] Open
Abstract
Background Electrical impedance tomography is a continuous imaging method capable of measuring lung volume changes. The purpose of this study was to examine whether EIT was capable of evaluating the degree of obstructive ventilatory defect (OVD) on the global and regional level. Methods 41 healthy subjects with no lung diseases and 67 subjects suffering from obstructive lung diseases were examined using EIT and spirometry during forced vital capacity (FVC) maneuver. The subjects were divided into control group (n = 41), early airway obstruction group (n = 26), mild group (n = 17), moderate group (n = 16) and severe group (n = 8) according to the degree of obstruction. Forced expiratory volume in 1 second (FEV1) and FEV1/FVC were determined by EIT. The mode index (MI) was proposed to evaluate the degree of global and regional obstruction; the effectiveness of MI was validated by evaluating posture related change of lung emptying capacity in sitting and supine postures; the degree of regional obstruction was determined according to the cut-off values of MI obtained from receiver operating characteristic (ROC) analysis; regional obstruction was located in the four-quadrant region of interest (ROI) and the contour-map ROI with contour lines at the cut-off values of MI. Results Significant differences were found between different groups (P<0.05) and the global MI was 0.93±0.03, 0.86±0.05, 0.81±0.09, 0.73±0.09 and 0.60±0.11 (mean ±SD), respectively. The cut-off MI value was 0.90, 0.83, 0.77, and 0.65, respectively. Conclusion The results indicated the potential of EIT to evaluate the degree of obstruction in patients with obstructive ventilatory defect on the global and regional level.
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Affiliation(s)
- Chao Zhang
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, Shaanxi, China.,Medical Engineering Section, General Hospital of Shenyang Military Region, Shenyang, Liaoning, China
| | - Meng Dai
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Wei Liu
- Department of respiratory medicine, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Xiaohui Bai
- The Fifth People's Hospital of Baoji City, Baoji, Shaanxi, China
| | - Jiaming Wu
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, Shaanxi, China.,Department of Medical Technology, Bethune Military Medical NCO Academy of PLA, Shijiazhuang, Hebei, China
| | - Canhua Xu
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Junying Xia
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Feng Fu
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Xuetao Shi
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Xiuzhen Dong
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Faguang Jin
- Department of respiratory medicine, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Fusheng You
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, Shaanxi, China
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13
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Mueller JL, Muller P, Mellenthin M, Murthy R, Capps M, Alsaker M, Deterding R, Sagel SD, DeBoer E. Estimating regions of air trapping from electrical impedance tomography data. Physiol Meas 2018; 39:05NT01. [PMID: 29726838 PMCID: PMC6015736 DOI: 10.1088/1361-6579/aac295] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Electrical impedance tomography (EIT) has been shown to be a viable non-invasive, bedside imaging modality to monitor lung function. This paper introduces a method for identifying regions of air trapping from EIT data collected during tidal breathing and breath-holding maneuvers. APPROACH Ventilation-perfusion index maps are computed from dynamic EIT images. These maps are then used to identify regions of air trapping in the area of the lung as regions that are poorly ventilated but well perfused throughout the breathing and cardiac cycles. These EIT-identified regions are then compared with independently identified regions of low attenuation, or air trapping, on chest CT. Results of this method are demonstrated in two children with cystic fibrosis and on a healthy control subject. MAIN RESULTS In both CF children, the EIT-identified regions of air trapping matched the regions indicated from the chest CT. The EIT-based method is only validated with CT scans within 4 cm of the chest cross-section defined by the electrode plane. SIGNIFICANCE The results indicate the potential use of EIT-derived ventilation-perfusion index maps as a non-invasive method for identifying regions of air trapping.
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Affiliation(s)
- Jennifer L Mueller
- Department of Mathematics, Colorado State University, Fort Collins, CO, United States of America. School of Biomedical Engineering, Colorado State University, Fort Collins, CO, United States of America
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14
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Ngo C, Dippel F, Tenbrock K, Leonhardt S, Lehmann S. Flow-volume loops measured with electrical impedance tomography in pediatric patients with asthma. Pediatr Pulmonol 2018; 53:636-644. [PMID: 29405616 DOI: 10.1002/ppul.23962] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 01/15/2018] [Indexed: 12/16/2022]
Abstract
BACKGROUND Electrical impedance tomography (EIT) provides information on global and regional ventilation during tidal breathing and mechanical ventilation. During forced expiration maneuvers, the linearity of EIT and spirometric data has been documented in healthy persons. The present study investigates the potential diagnostic use of EIT in pediatric patients with asthma. METHODS EIT and spirometry were performed in 58 children with asthma (average age ± SD: 11.86 ± 3.13 years), and 58 healthy controls (average age ± SD: 12.12 ± 2.9 years). The correlation between EIT data and simultaneously acquired spirometric data were tested for FEV1, FEV0.5 , MEF75 , MEF50 , and MEF25 . Binary classification tests were performed for the EIT-derived Tiffeneau index FEV1 /FVC and the bronchodilator test index ΔFEV1 . Average flow-volume (FV) loops were generated for patients with pathologic spirometry to demonstrate the feasibility of EIT for graphic diagnosis of asthma. RESULTS Spirometry and global EIT-based FV loops showed a strong correlation (P < 0.001, r > 0.9 in FEV1 and FEV0.5 ). In all criteria, the binary classification tests yielded high specificity (>93%), a high positive predictive value (≥75%) and a high negative predictive value (>80%), while sensitivity was higher in ΔFEV1 (86.67%) and lower in FEV1 /FVC (25% and 35.29%). A typical concave shape of the EIT-derived average FV loops was observed for asthmatic children with improvement after bronchospasmolysis. CONCLUSIONS Global FV loops derived from EIT correlate well with spirometry. Positive bronchospasmolysis can be observed in EIT-derived FV loops. Flow-volume loops originated from EIT have a potential to visualize pulmonary function.
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Affiliation(s)
- Chuong Ngo
- Philips Chair for Medical Information Technology, RWTH Aachen, Aachen, Germany
| | - Falk Dippel
- Philips Chair for Medical Information Technology, RWTH Aachen, Aachen, Germany
| | - Klaus Tenbrock
- Department of Pediatric Pulmonology, RWTH Aachen University Hospital, Aachen, Germany
| | - Steffen Leonhardt
- Philips Chair for Medical Information Technology, RWTH Aachen, Aachen, Germany
| | - Sylvia Lehmann
- Department of Pediatric Pulmonology, RWTH Aachen University Hospital, Aachen, Germany
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15
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Muller PA, Mueller JL, Mellenthin M, Murthy R, Capps M, Wagner BD, Alsaker M, Deterding R, Sagel SD, Hoppe J. Evaluation of surrogate measures of pulmonary function derived from electrical impedance tomography data in children with cystic fibrosis. Physiol Meas 2018; 39:045008. [PMID: 29565263 DOI: 10.1088/1361-6579/aab8c4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Lung function monitoring by spirometry plays a critical role in the clinical care of pediatric cystic fibrosis (CF) patients, but many young children are unable to perform spirometry, and the outputs are often normal even in the presence of lung disease. Measures derived from electrical impedance tomography (EIT) images were studied for their utility as potential surrogates for spirometry in CF patients and to assess response to intravenous antibiotic treatment for acute pulmonary exacerbations (PEx) in a subset of patients. APPROACH EIT data were collected on 35 subjects (21 with CF, 14 healthy controls, 8 CF patients pre- and post-treatment for an acute PEx) ages 2 to 20 years during tidal breathing and also concurrently with spirometry on subjects over age 8. EIT-derived measures of FEV1, FVC, and FEV1/FVC were computed globally and regionally from dynamic EIT images. MAIN RESULTS Global EIT-derived FEV1/FVC showed good correlation with spirometry FEV1/FVC values (r = 0.54, p = 0.01), and were able to distinguish between the groups (p = 0.01). Lung heterogeneity was assessed through the spatial coefficient of variation (CV) of EIT difference images between key time points, and the CVs for EIT-derived FEV1 and FVC showed significant correlation with the CV for tidal breathing (r = 0.47, p = 0.01 and r = 0.50, p = 0.01, respectively). Global EIT-derived FEV1/FVC was better able to distinguish between groups than spirometry FEV1 (F-values 776.5 and 146.3, respectively, p < 0.01.) The same held true for the CVs for EIT-derived FEV1, FVC, and tidal breathing (F-values 215.93, 193.89, 204.57, respectively, p < 0.01). SIGNIFICANCE The strong correlation between the CVs for tidal breathing, FEV1, and FVC, and the statistically significant ability of CV for tidal breathing to distinguish between healthy subjects and CF patients, and between the studied CF disease states suggests that the CV may be useful for measuring the extent and severity of structural lung disease.
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Affiliation(s)
- Peter A Muller
- Department of Mathematics & Statistics, Villanova University, PA, United States of America. was at Department of Mathematics, Colorado State University, CO, United States of America
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16
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Vogt B, Löhr S, Zhao Z, Falkenberg C, Ankermann T, Weiler N, Frerichs I. Regional lung function testing in children using electrical impedance tomography. Pediatr Pulmonol 2018; 53:293-301. [PMID: 29136345 DOI: 10.1002/ppul.23912] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 10/03/2017] [Accepted: 10/22/2017] [Indexed: 11/10/2022]
Abstract
OBJECTIVE To evaluate regional lung function in lung-healthy children before and after exercise challenge using electrical impedance tomography (EIT). METHODS Regional lung function was examined using EIT in 100 lung-healthy children (three age subgroups: 74-121, 122-155, 156-195 months) at baseline and 10 min after exercise. Global lung function was assessed by spirometry using Z-Scores of FEV1 , FVC, FEV1 /FVC, and FEF75 . The same lung function measures were determined in 912 EIT image pixels to enable the spatial and temporal ventilation distribution analysis. Coefficients of variation (CV) of these pixel values were calculated and histograms of pixel FEV1 /FVC and times required to exhale 50% and 75% of pixel FVC (t50 and t75 ) generated. Additionally, we compared the findings of the studied population with three cystic fibrosis (CF) children. FINDINGS Z-Scores corresponded to the worldwide reference values in all studied age groups at baseline. Global lung function was not affected by exercise, only the youngest group exhibited higher FVC and lower FEF75 , FEV1 /FVC attributable to the training effect. The overall degree of ventilation heterogeneity assessed by CV showed no exercise dependency. The histograms of pixel values of FEV1 /FVC, t50 , and t75 revealed a slight modulating effect of exercise on regional ventilation distribution in all subgroups. EIT identified the distinctly higher ventilation heterogeneity in the CF children. CONCLUSION Global and regional lung functions were not affected by exercise in lung-healthy children. Exercise did not increase ventilation inhomogeneity. The obtained EIT-derived regional lung parameters can serve as reference values for future studies in children with lung diseases.
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Affiliation(s)
- Barbara Vogt
- Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Sarah Löhr
- Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Zhanqi Zhao
- Department of Biomedical Engineering, Furtwangen University, Villingen-Schwenningen, Germany
| | - Christian Falkenberg
- Rehabilitation Center for Children and Adolescents, Fachklinik Satteldüne, Nebel, Germany
| | - Tobias Ankermann
- Department of Pediatric Pulmonology, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Norbert Weiler
- Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Inéz Frerichs
- Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
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17
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Krueger-Ziolek S, Schullcke B, Gong B, Müller-Lisse U, Moeller K. EIT based pulsatile impedance monitoring during spontaneous breathing in cystic fibrosis. Physiol Meas 2018; 38:1214-1225. [PMID: 28530203 DOI: 10.1088/1361-6579/aa69d5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Evaluating the lung function in patients with obstructive lung disease by electrical impedance tomography (EIT) usually requires breathing maneuvers containing deep inspirations and forced expirations. Since these maneuvers strongly depend on the patient's co-operation and health status, normal tidal breathing was investigated in an attempt to develop continuous maneuver-free measurements. APPROACH Ventilation related and pulsatile impedance changes were systematically analyzed during normal tidal breathing in 12 cystic fibrosis (CF) patients and 12 lung-healthy controls (HL). Tidal breaths were subdivided into three inspiratory (In1, In2, In3) and three expiratory (Ex1, Ex2, Ex3) sections of the same amplitude of global impedance change. Maximal changes of the ventilation and the pulsatile impedance signal occurring during these sections were determined (▵I V and ▵I P). Differences in ▵I V and ▵I P among sections were ascertained in relation to the first inspiratory section. In addition, ▵I V/▵I P was calculated for each section. MAIN RESULTS Medians of changes in ▵I V were <0.05% in all sections for both subject groups. Both groups showed a similar pattern of ▵I P changes during tidal breathing. Changes in ▵I P first decreased during inspiration (In2), then increased towards the end of inspiration (In3) and reached a maximum at the beginning of expiration (Ex1). During the last two sections of expiration (Ex2, Ex3) ▵I P changes decreased. The CF patients showed higher variations in ▵I P changes compared to the controls (CF: -426.5%, HL: -158.1%, coefficient of variation). Furthermore, ▵I V/▵I P significantly differed between expiratory sections for the CF patients (Ex1-Ex2, p < 0.01; Ex1-Ex3, p < 0.001; Ex2-Ex3, p < 0.05), but not for the controls. No significant differences in ▵I V/▵I P between inspiratory sections were determined for both groups. SIGNIFICANCE Differences in ▵I P changes and in ▵I V/▵I P between both subject groups were speculated to be caused by higher breathing efforts of the CF patients due to airway obstruction leading to higher intrathoracic pressures, and thus to greater changes in lung perfusion.
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Affiliation(s)
- Sabine Krueger-Ziolek
- Institute of Technical Medicine, Furtwangen University, Jakob-Kienzle-Straße 17, 78054 Villingen-Schwenningen, Germany. Department of Radiology, LMU University of Munich, Ziemssenstrasse 1, 80336 Munich, Germany3
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18
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Savant AP, McColley SA. Cystic fibrosis year in review 2016. Pediatr Pulmonol 2017; 52:1092-1102. [PMID: 28608632 DOI: 10.1002/ppul.23747] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 05/15/2017] [Indexed: 12/26/2022]
Abstract
In this article, we highlight cystic fibrosis (CF) research and case reports published in Pediatric Pulmonology during 2016. We also include articles from a variety of journals that are thematically related to these articles, or are of special interest to clinicians.
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Affiliation(s)
- Adrienne P Savant
- Division of Pulmonary Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, Illinois.,Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Susanna A McColley
- Division of Pulmonary Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, Illinois.,Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois.,Stanley Manne Children's Resear ch Institute, Chicago, Illinois
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19
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Ngo C, Leonhardt S, Zhang T, Lüken M, Misgeld B, Vollmer T, Tenbrock K, Lehmann S. Linearity of electrical impedance tomography during maximum effort breathing and forced expiration maneuvers. Physiol Meas 2016; 38:77-86. [PMID: 28004642 DOI: 10.1088/1361-6579/38/1/77] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Electrical impedance tomography (EIT) provides global and regional information about ventilation by means of relative changes in electrical impedance measured with electrodes placed around the thorax. In combination with lung function tests, e.g. spirometry and body plethysmography, regional information about lung ventilation can be achieved. Impedance changes strictly correlate with lung volume during tidal breathing and mechanical ventilation. Initial studies presumed a correlation also during forced expiration maneuvers. To quantify the validity of this correlation in extreme lung volume changes during forced breathing, a measurement system was set up and applied on seven lung-healthy volunteers. Simultaneous measurements of changes in lung volume using EIT imaging and pneumotachography were obtained with different breathing patterns. Data was divided into a synchronizing phase (spontaneous breathing) and a test phase (maximum effort breathing and forced maneuvers). The EIT impedance changes correlate strictly with spirometric data during slow breathing with increasing and maximum effort ([Formula: see text]) and during forced expiration maneuvers ([Formula: see text]). Strong correlations in spirometric volume parameters [Formula: see text] ([Formula: see text]), [Formula: see text]/FVC ([Formula: see text]), and flow parameters PEF, [Formula: see text], [Formula: see text], [Formula: see text] ([Formula: see text]) were observed. According to the linearity during forced expiration maneuvers, EIT can be used during pulmonary function testing in combination with spirometry for visualisation of regional lung ventilation.
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Affiliation(s)
- Chuong Ngo
- Philips Chair of Medical Information Technology, Helmholtz-Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany
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20
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Krueger-Ziolek S, Schullcke B, Zhao Z, Gong B, Naehrig S, Müller-Lisse U, Moeller K. Multi-layer ventilation inhomogeneity in cystic fibrosis. Respir Physiol Neurobiol 2016; 233:25-32. [PMID: 27476932 DOI: 10.1016/j.resp.2016.07.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 07/27/2016] [Accepted: 07/28/2016] [Indexed: 11/18/2022]
Abstract
Differences in regional lung function between the 3rd and 5th intercostal space (ICS) were explored in 10 cystic fibrosis (CF) patients and compared to 10 lung-healthy controls by electrical impedance tomography (EIT). Regional ratios of impedance changes corresponding to the maximal volume of air exhaled within the first second of a forced expiration (ΔIFEV1) and the forced vital capacity (ΔIFVC) were determined. Regional airway obstruction and ventilation inhomogeneity were assessed by the frequency distribution of these ratios (ΔIFEV1/ΔIFVC) and an inhomogeneity index (GITI). The mean of the frequency distribution of ΔIFEV1/ΔIFVC and the GITI in both thorax planes were significantly different between CF patients and controls (p<0.001). CF patients exhibited a significantly lower mean of ΔIFEV1/ΔIFVC frequency distribution (p<0.05) and a significantly higher degree of ventilation inhomogeneity (p<0.01) in the 3rd ICS compared to the 5th ICS. Results indicated that EIT measurements at more cranial thorax planes may benefit the early diagnosis in CF.
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Affiliation(s)
- Sabine Krueger-Ziolek
- Institute of Technical Medicine, Furtwangen University, Jakob-Kienzle-Straße 17, 78054 Villingen-Schwenningen, Germany; Department of Radiology, LMU University of Munich, Ziemssenstrasse 1, 80336 Munich, Germany(1).
| | - Benjamin Schullcke
- Institute of Technical Medicine, Furtwangen University, Jakob-Kienzle-Straße 17, 78054 Villingen-Schwenningen, Germany; Department of Radiology, LMU University of Munich, Ziemssenstrasse 1, 80336 Munich, Germany(1)
| | - Zhanqi Zhao
- Institute of Technical Medicine, Furtwangen University, Jakob-Kienzle-Straße 17, 78054 Villingen-Schwenningen, Germany
| | - Bo Gong
- Institute of Technical Medicine, Furtwangen University, Jakob-Kienzle-Straße 17, 78054 Villingen-Schwenningen, Germany; Department of Radiology, LMU University of Munich, Ziemssenstrasse 1, 80336 Munich, Germany(1)
| | - Susanne Naehrig
- Medizinische Klinik V (Pneumology), LMU University of Munich, Ziemssenstrasse 1, 80336 Munich, Germany(1)
| | - Ullrich Müller-Lisse
- Department of Radiology, LMU University of Munich, Ziemssenstrasse 1, 80336 Munich, Germany(1)
| | - Knut Moeller
- Institute of Technical Medicine, Furtwangen University, Jakob-Kienzle-Straße 17, 78054 Villingen-Schwenningen, Germany
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