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electrical impedance tomography

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https://www.readbyqxmd.com/read/28632138/monitoring-lung-contusion-in-a-porcine-polytrauma-model-using-eit-an-application-study
#1
Susana Aguiar Santos, Carlos Castelar Wembers, Klemens Horst, Roman Pfeifer, Tim-Philipp Simon, Hans-Christoph Pape, Frank Hildebrand, Michael Czaplik, Steffen Leonhardt, Daniel Teichmann
Lung contusion is the most common lung injury following blunt chest trauma which, in turn, is associated with high mortality rates (Gavelli et al., 2002). Lung contusion is characterized by hemorrhage and edema with consecutively reduced compliance. In this study, unilateral lung contusion and other traumata were induced in 12 pigs by using a bolt gun machine. To investigate the pathophysiological consequences of lung contusion, information on clinical parameters was collected and monitored regularly while animals were additionally monitored with electrical impedance tomography (EIT) before trauma, and at 4, 24, 48 and 72 h after polytrauma...
June 20, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28628556/real-time-imaging-of-epileptic-seizures-in-rats-using-electrical-impedance-tomography
#2
Lei Wang, Yang Sun, Xinmin Xu, Xiuzhen Dong, Feng Gao
The presence of multiple or diffuse lesions on imaging is a contraindication to surgery for patients with intractable epilepsy. Theoretically, as a functional imaging technique, electrical impedance tomography (EIT) can accurately image epileptic foci. However, most current studies are limited to examining epileptic spikes and few studies use EIT for real-time imaging of seizure activity. Moreover, little is known about changes in electrical impedance during seizures. In this study, we used EIT to monitor seizure progression in real time and analyzed changes in electrical impedance during seizures...
June 16, 2017: Neuroreport
https://www.readbyqxmd.com/read/28614900/computational-method-for-estimating-boundary-of-abdominal-subcutaneous-fat-for-absolute-electrical-impedance-tomography
#3
Tohru F Yamaguchi, Yoshiwo Okamoto
Abdominal fat accumulation is considered an essential indicator of human health. Electrical impedance tomography has considerable potential for abdominal fat imaging because of the low specific conductivity of human body fat. In this paper, we propose a robust reconstruction method for high-fidelity conductivity imaging by abstraction of the abdominal cross section using a relatively small number of parameters. Toward this end, we assume homogeneous conductivity in the abdominal subcutaneous fat area, and characterize its geometrical shape by parameters defined as the ratio of the distance from the center to boundary of subcutaneous fat to the distance from the center to outer boundary in 64 equiangular directions...
June 14, 2017: International Journal for Numerical Methods in Biomedical Engineering
https://www.readbyqxmd.com/read/28604757/time-to-lung-aeration-during-a-sustained-inflation-at-birth-is-influenced-by-gestation-in-lambs
#4
Karen E McCall, Andreas D Waldmann, Prue Pereira-Fantini, Regina Oakley, M Miedema, Elizabeth J Perkins, Peter G Davis, Peter A Dargaville, Stephan H Böhm, Raffaele Dellacà, Magdy Sourial, Emanuela Zannin, Anushi Rajapaksa, Andre Tan, Andy Adler, Inéz Frerichs, David G Tingay
BACKGROUND: Current sustained lung inflation (SI) approaches use uniform pressures and durations. We hypothesised that gestational age related mechanical and developmental differences would affect the time required to achieve optimal lung aeration, and resultant lung volumes, during SI delivery at birth in lambs. METHODS: 49 lambs, in five cohorts between 118d and 139d gestation (term 142d), received a standardised 40 cmH2O SI, delivered until 10 s after lung volume stability (optimal aeration) was visualised on real-time electrical impedance tomography (EIT), or to a maximum duration of 180 s...
June 12, 2017: Pediatric Research
https://www.readbyqxmd.com/read/28578708/effects-of-neurally-adjusted-ventilatory-assist-on-air-distribution-and-dead-space-in-patients-with-acute-exacerbation-of-chronic-obstructive-pulmonary-disease
#5
Qin Sun, Ling Liu, Chun Pan, Zhanqi Zhao, Jingyuan Xu, Airan Liu, Haibo Qiu
BACKGROUND: Neurally adjusted ventilatory assist (NAVA) could improve patient-ventilator interaction; its effects on ventilation distribution and dead space are still unknown. The aim of this study was to evaluate the effects of varying levels of assist during NAVA and pressure support ventilation (PSV) on ventilation distribution and dead space in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). METHODS: Fifteen mechanically ventilated patients with AECOPD were included in the study...
June 2, 2017: Critical Care: the Official Journal of the Critical Care Forum
https://www.readbyqxmd.com/read/28572979/complex-effects-of-high-flow-nasal-cannula-therapy-on-hemodynamics-in-the-pediatric-patient-after-cardiac-surgery
#6
EDITORIAL
Yu Inata, Muneyuki Takeuchi
BACKGROUND: The high-flow nasal cannula (HFNC) system has been widely used for children in various clinical settings. However, the physiological and clinical impact of HFNC therapy on the pediatric patient with respiratory distress after cardiac surgery has not been thoroughly investigated. MAIN BODY OF THE ABSTRACT: It seems logical to use HFNC as a primary therapy for post-extubation respiratory failure after congenital heart surgery, in which low cardiac output syndrome and upper airway obstruction are commonly encountered; the HFNC therapy alleviates the work of breathing and large negative swings of intrathoracic pressure, which in turn helps to decrease the systemic ventricular afterload...
2017: Journal of Intensive Care
https://www.readbyqxmd.com/read/28564589/functional-monitoring-of-peripheral-nerves-from-electrical-impedance-measurements
#7
Alexandre Fouchard, Véronique Coizet, Valérie Sinniger, Didier Clarençon, Karin Pernet-Gallay, Stéphane Bonnet, Olivier David
Medical electrical stimulators adapted to peripheral nerves use multicontact cuff electrodes (MCC) to provide selective neural interfaces. However, neuroprostheses are currently limited by their inability to locate the regions of interest to focus. Intended until now either for stimulation or recording, MCC can also be used as a means of transduction to characterize the nerve by impedancemetry. In this study, we investigate the feasibility of using electrical impedance (EI) measurements as an in vivo functional nerve monitoring technique...
June 2, 2017: Journal of Physiology, Paris
https://www.readbyqxmd.com/read/28560836/sensitivity-analysis-of-magnetic-field-measurements-for-magnetic-resonance-electrical-impedance-tomography-mreit
#8
Cihan Göksu, Klaus Scheffler, Philipp Ehses, Lars G Hanson, Axel Thielscher
PURPOSE: Clinical use of magnetic resonance electrical impedance tomography (MREIT) still requires significant sensitivity improvements. Here, the measurement of the current-induced magnetic field (ΔBz,c ) is improved using systematic efficiency analyses and optimization of multi-echo spin echo (MESE) and steady-state free precession free induction decay (SSFP-FID) sequences. THEORY AND METHODS: Considering T1 , T2 , and T2* relaxation in the signal-to-noise ratios (SNRs) of the MR magnitude images, the efficiency of MESE and SSFP-FID MREIT experiments, and its dependence on the sequence parameters, are analytically analyzed and simulated...
May 30, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28546376/noninvasive-monitoring-of-oxygen-and-ventilation
#9
Craig D Smallwood, Brian K Walsh
Noninvasive monitoring of oxygenation and ventilation is an essential part of pediatric respiratory care. Carbon dioxide, gas exchange monitoring, transcutaneous monitoring, near-infrared spectroscopy, pulse oximetry, and electrical impedance tomography are examined. Although some of these technologies have been utilized for decades, incorporation into mechanical ventilators and recently developed methods may provide important clinical insights in a broader patient range. Less mature technologies (electrical impedance tomography and near-infrared spectroscopy) have been of particular interest, since they offer easy bedside application and potential for improved care of children with respiratory failure and other disorders...
June 2017: Respiratory Care
https://www.readbyqxmd.com/read/28545875/regional-volume-characteristics-of-the-preterm-infant-receiving-first-intention-continuous-positive-airway-pressure
#10
Risha Bhatia, Peter G Davis, David G Tingay
OBJECTIVE: To determine whether applying nasal continuous positive airway pressure (CPAP) using systematic changes in continuous distending pressure (CDP) results in a quasi-static pressure-volume relationship in very preterm infants receiving first intention CPAP in the first 12-18 hours of life. STUDY DESIGN: Twenty infants at <32 weeks' gestation with mild respiratory distress syndrome (RDS) managed exclusively with nasal CPAP had CDP increased from 5 to 8 to 10 cmH2O, and then decreased to 8 cmH2O and returned to baseline CDP...
May 22, 2017: Journal of Pediatrics
https://www.readbyqxmd.com/read/28535788/endexpiratory-lung-volume-measurement-correlates-with-the-ventilation-perfusion-mismatch-in-lung-injured-pigs
#11
Jens Kamuf, Andreas Garcia-Bardon, Bastian Duenges, Tanghua Liu, Antje Jahn-Eimermacher, Florian Heid, Matthias David, Erik K Hartmann
BACKGROUND: In acute respiratory respiratory distress syndrome (ARDS) a sustained mismatch of alveolar ventilation and perfusion (VA/Q) impairs the pulmonary gas exchange. Measurement of endexpiratory lung volume (EELV) by multiple breath-nitrogen washout/washin is a non-invasive, bedside technology to assess pulmonary function in mechanically ventilated patients. The present study examines the association between EELV changes and VA/Q distribution and the possibility to predict VA/Q normalization by means of EELV in a porcine model...
May 23, 2017: Respiratory Research
https://www.readbyqxmd.com/read/28535624/-utilisation-of-electrical-impedance-tomography-and-or-ultrasound-and-mammography-in-breast-disease-diagnosis-a-controlled-study
#12
F Xu, M X Li, H Z Jusko, Hongchuan Jiang
Objective: To investigate the diagnostic accuracy of electrical impedance tomography (EIT) for benign and malignant breast diseases incomparison to conventional ultrasonography and mammography. Methods: A total of 121 patients with 126 breast lesions who underwent mammography ultrasonography and EIT were enrolled in the study. All of these lessions were were confirmed by pathological biopsy. The accuracy, sensitivity, specificity, positive predictive value and negative predictive value of EIT, ultrasonography and mammography were calculated with histology as the gold standard...
May 16, 2017: Zhonghua Yi Xue za Zhi [Chinese medical journal]
https://www.readbyqxmd.com/read/28530209/reproducible-3d-printed-head-tanks-for-electrical-impedance-tomography-with-realistic-shape-and-conductivity-distribution
#13
James Avery, Kirill Aristovich, Barney Low, David Holder
OBJECTIVE: Electrical impedance tomography (EIT) has many promising applications in brain injury monitoring. To evaluate both instrumentation and reconstruction algorithms, experiments are first performed in head tanks. Existing methods, whilst accurate, produce a discontinuous conductivity, and are often made by hand, making it hard for other researchers to replicate. APPROACH: We have developed a method for constructing head tanks directly in a 3D printer. Conductivity was controlled through perforations in the skull surface, which allow for saline to pass through...
May 22, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28530208/eit-imaging-of-admittivities-with-a-d-bar-method-and-spatial-prior-experimental-results-for-absolute-and-difference-imaging
#14
S J Hamilton
Electrical impedance tomography (EIT) is an emerging imaging modality that uses harmless electrical measurements taken on electrodes at a body's surface to recover information about the internal electrical conductivity and or permittivity. The image reconstruction task of EIT is a highly nonlinear inverse problem that is sensitive to noise and modeling errors making the image reconstruction task challenging. D-bar methods solve the nonlinear problem directly, bypassing the need for detailed and time-intensive forward models, to provide absolute (static) as well as time-difference EIT images...
May 22, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28530206/16th-international-conference-on-electrical-bio-impedance-and-17th-international-conference-on-biomedical-applications-of-electrical-impedance-tomography-eit
#15
Richard Bayford, Stig Ollmar
No abstract text is available yet for this article.
May 22, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28530205/phantom-experiments-using-soft-prior-regularization-eit-for-breast-cancer-imaging
#16
Ethan K Murphy, Aditya Mahara, Xiaotian Wu, Ryan J Halter
OBJECTIVE: A soft-prior regularization (SR) electrical impedance tomography (EIT) technique for breast cancer imaging is described, which shows an ability to accurately reconstruct tumor/inclusion conductivity values within a dense breast model investigated using a cylindrical and a breast-shaped tank. APPROACH: The SR-EIT method relies on knowing the spatial location of a suspicious lesion initially detected from a second imaging modality. Standard approaches (using Laplace smoothing and total variation regularization) without prior structural information are unable to accurately reconstruct or detect the tumors...
June 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28530203/eit-based-pulsatile-impedance-monitoring-during-spontaneous-breathing-in-cystic-fibrosis
#17
Sabine Krueger-Ziolek, Benjamin Schullcke, Bo Gong, Ullrich Müller-Lisse, Knut Moeller
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)...
June 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28457836/imaging-of-current-flow-in-the-human-head-during-transcranial-electrical-therapy
#18
A K Kasinadhuni, A Indahlastari, M Chauhan, Michael Schär, T H Mareci, R J Sadleir
BACKGROUND: It has been assumed that effects caused by tDCS or tACS neuromodulation are due to electric current flow within brain structures. However, to date, direct current density distributions in the brains of human subjects have not been measured. Instead computational models of tDCS or tACS have been used to predict electric current and field distributions for dosimetry and mechanism analysis purposes. OBJECTIVE/HYPOTHESIS: We present the first in vivo images of electric current density distributions within the brain in four subjects undergoing transcranial electrical stimulation...
July 2017: Brain Stimulation
https://www.readbyqxmd.com/read/28457827/ventilation-distribution-assessed-with-electrical-impedance-tomography-and-the-influence-of-tidal-volume-recruitment-and-positive-end-expiratory-pressure-in-isoflurane-anesthetized-dogs
#19
Aline M Ambrosio, Tatiana P A Carvalho-Kamakura, Keila K Ida, Barbara Varela, Felipe S R M Andrade, Lara L Facó, Denise T Fantoni
OBJECTIVE: To examine the intrapulmonary gas distribution of low and high tidal volumes (VT) and to investigate whether this is altered by an alveolar recruitment maneuver (ARM) and 5 cmH2O positive end-expiratory pressure (PEEP) during anesthesia. STUDY DESIGN: Prospective randomized clinical study. ANIMALS: Fourteen client-owned bitches weighing 26 ± 7 kg undergoing elective ovariohysterectomy. METHODS: Isoflurane-anesthetized dogs in dorsal recumbency were ventilated with 0 cmH2O PEEP and pressure-controlled ventilation by adjusting the peak inspiratory pressure (PIP) to achieve a low (7 mL kg(-1); n = 7) or a high (12 mL kg(-1); n = 7) VT...
March 2017: Veterinary Anaesthesia and Analgesia
https://www.readbyqxmd.com/read/28452241/respiratory-monitoring-in-adult-intensive-care-unit
#20
Pongdhep Theerawit, Yuda Sutherasan, Lorenzo Ball, Paolo Pelosi
The mortality of patients with respiratory failure has steadily decreased with the advancements in protective ventilation and treatment options. Although respiratory monitoring per se has not been proven to affect the mortality of critically ill patients, it plays a crucial role in patients' care, as it helps to titrate the ventilatory support. Several new monitoring techniques have recently been made available at the bedside. The goals of monitoring comprise alerting physicians to detect the change in the patients' conditions, to improve the understanding of pathophysiology to guide the diagnosis and provide cost-effective clinical management...
June 2017: Expert Review of Respiratory Medicine
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