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electrical impedance tomography

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https://www.readbyqxmd.com/read/29323536/high-positive-end-expiratory-pressure-renders-spontaneous-effort-non-injurious
#1
Caio C A Morais, Yukiko Koyama, Takeshi Yoshida, Glauco M Plens, Susimeire Gomes, Cristhiano L A S Lima, Ozyres P Ramos, Sérgio M Pereira, Naomasa Kawaguchi, Hirofumi Yamamoto, Akinori Uchiyama, João B Borges, Marcos F Vidal Melo, Mauro R Tucci, Marcelo B P Amato, Brian P Kavanagh, Eduardo L V Costa, Yuji Fujino
RATIONALE: In ARDS, atelectatic 'solid-like' lung tissue impairs transmission of negative 'swings' in pleural pressure (Ppl) resulting from diaphragmatic contraction. The localization of more negative Ppl proportionally increases dependent lung stretch by drawing gas either from other lung regions, e.g., non-dependent lung (Pendelluft) or from the ventilator. Lowering of the level of spontaneous effort and/or converting solid-like to fluid-like lung might render spontaneous effort non-injurious...
January 11, 2018: American Journal of Respiratory and Critical Care Medicine
https://www.readbyqxmd.com/read/29321483/extracellular-total-electrolyte-concentration-imaging-for-electrical-brain-stimulation-ebs
#2
Saurav Z K Sajib, Mun Bae Lee, Hyung Joong Kim, Eung Je Woo, Oh In Kwon
Techniques for electrical brain stimulation (EBS), in which weak electrical stimulation is applied to the brain, have been extensively studied in various therapeutic brain functional applications. The extracellular fluid in the brain is a complex electrolyte that is composed of different types of ions, such as sodium (Na+), potassium (K+), and calcium (Ca+). Abnormal levels of electrolytes can cause a variety of pathological disorders. In this paper, we present a novel technique to visualize the total electrolyte concentration in the extracellular compartment of biological tissues...
January 10, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29301446/real-time-estimation-of-lesion-depth-and-control-of-radiofrequency-ablation-within-ex-vivo-animal-tissues-using-a-neural-network
#3
Yearnchee Curtis Wang, Terence Chee-Hung Chan, Alan Varteres Sahakian
BACKGROUND: Radiofrequency ablation (RFA), a method of inducing thermal ablation (cell death), is often used to destroy tumours or potentially cancerous tissue. Current techniques for RFA estimation (electrical impedance tomography, Nakagami ultrasound, etc.) require long compute times (≥ 2 s) and measurement devices other than the RFA device. This study aims to determine if a neural network (NN) can estimate ablation lesion depth for control of bipolar RFA using complex electrical impedance - since tissue electrical conductivity varies as a function of tissue temperature - in real time using only the RFA therapy device's electrodes...
January 4, 2018: International Journal of Hyperthermia
https://www.readbyqxmd.com/read/29288869/human-in-vivo-brain-magnetic-resonance-current-density-imaging-mrcdi
#4
Cihan Göksu, Lars G Hanson, Hartwig R Siebner, Philipp Ehses, Klaus Scheffler, Axel Thielscher
Magnetic resonance current density imaging (MRCDI) and MR electrical impedance tomography (MREIT) are two emerging modalities, which combine weak time-varying currents injected via surface electrodes with magnetic resonance imaging (MRI) to acquire information about the current flow and ohmic conductivity distribution at high spatial resolution. The injected current flow creates a magnetic field in the head, and the component of the induced magnetic field ΔBz,c parallel to the main scanner field causes small shifts in the precession frequency of the magnetization...
December 27, 2017: NeuroImage
https://www.readbyqxmd.com/read/29225613/a-multitasking-electrical-impedance-tomography-system-using-titanium-alloy-electrode
#5
Abdalla Salama, Amin Malekmohammadi, Shahram Mohanna, Rajprasad Rajkumar
This paper presents a multitasking electrical impedance tomography (EIT) system designed to improve the flexibility and durability of an existing EIT system. The ability of the present EIT system to detect, locate, and reshape objects was evaluated by four different experiments. The results of the study show that the system can detect and locate an object with a diameter as small as 1.5 mm in a testing tank with a diameter of 134 mm. Moreover, the results demonstrate the ability of the current system to reconstruct an image of several dielectric object shapes...
2017: International Journal of Biomedical Imaging
https://www.readbyqxmd.com/read/29222030/regional-ventilation-distribution-and-dead-space-in-anaesthetised-horses-treated-with-and-without-continuous-positive-airway-pressure-novel-insights-by-electrical-impedance-tomography-and-volumetric-capnography
#6
Martina Mosing, Ulrike Auer, Paul MacFarlane, David Bardell, Johannes P Schramel, Stephan H Böhm, Regula Bettschart-Wolfensberger, Andreas D Waldmann
OBJECTIVE: The aim of this study was to evaluate the effect of continuous positive airway pressure (CPAP) on regional distribution of ventilation and dead space in anaesthetized horses. STUDY DESIGN: Randomized, experimental, crossover study. ANIMALS: A total of eight healthy adult horses. METHODS: Horses were anaesthetized twice with isoflurane in 50% oxygen and medetomidine as continuous infusion in dorsal recumbency, and administered in random order either CPAP (8 cmH2O) or NO CPAP for 3 hours...
July 3, 2017: Veterinary Anaesthesia and Analgesia
https://www.readbyqxmd.com/read/29206856/a-novel-post-processing-scheme-for-two-dimensional-electrical-impedance-tomography-based-on-artificial-neural-networks
#7
Sébastien Martin, Charles T M Choi
OBJECTIVE: Electrical Impedance Tomography (EIT) is a powerful non-invasive technique for imaging applications. The goal is to estimate the electrical properties of living tissues by measuring the potential at the boundary of the domain. Being safe with respect to patient health, non-invasive, and having no known hazards, EIT is an attractive and promising technology. However, it suffers from a particular technical difficulty, which consists of solving a nonlinear inverse problem in real time...
2017: PloS One
https://www.readbyqxmd.com/read/29206639/electrical-impedance-tomography-in-children-with-community-acquired-pneumonia-preliminary-data
#8
Marta B Mazzoni, Alessandra Perri, Anna M Plebani, Silvia Ferrari, Giacomo Amelio, Alessia Rocchi, Dario Consonni, Gregorio P Milani, Emilio F Fossali
BACKGROUND: Electrical impedance tomography (EIT) is a noninvasive pulmonary function test that provides spatial and temporal information of changes in regional lung ventilation. We aimed to assess the feasibility of EIT as a supplementary tool in the evaluation of community acquired pneumonia in children. Furthermore, we performed a prospective evaluation of regional lung ventilation changes during a six-month follow-up period. METHODS: We enrolled otherwise healthy children aged 2-15 years with radiological diagnosis of community acquired pneumonia on admission at pediatric emergency department...
September 2017: Respiratory Medicine
https://www.readbyqxmd.com/read/29145478/electrical-impedance-tomography-amplitudes-of-cardiac-related-impedance-changes-in-the-lung-are-highly-position-dependent
#9
Michael Graf, Thomas Riedel
BACKGROUND: Electrical impedance tomography (EIT) is used on the thorax to measure impedance changes due to the presence of air and blood in the lung. This experimental study was performed to investigate the effect of posture on cardiac and respiratory related impedance changes. METHODS: EIT measurements were performed on 14 healthy subjects in left-, right lateral, prone, supine and upright positions. Simultaneously, tidal volume was recorded with an ultrasonic flowmeter...
2017: PloS One
https://www.readbyqxmd.com/read/29136345/regional-lung-function-testing-in-children-using-electrical-impedance-tomography
#10
Barbara Vogt, Sarah Löhr, Zhanqi Zhao, Christian Falkenberg, Tobias Ankermann, Norbert Weiler, Inéz Frerichs
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...
November 14, 2017: Pediatric Pulmonology
https://www.readbyqxmd.com/read/29135866/importance-of-perimodiolar-electrode-position-for-psychoacoustic-discrimination-in-cochlear-implantation
#11
Angel Ramos Macias, Maria Teresa Perez Zaballos, Angel Ramos de Miguel, Javier Cervera Paz
HYPOTHESIS: Modiolar proximity of the cochlear implant electrodes and low impedance values have a positive effect on electrical pitch discrimination. BACKGROUND: The proximity of the cochlear electrode to the modiolar wall can determine changes in tissue and fluid environment. With the onset of soft-surgery techniques, the trauma caused during surgery has been reduced, minimizing fibrous growth. METHODS: Computed tomography-scan measurements of electrode-inner wall distance and psychoacoustic electrode discrimination tests were done...
December 2017: Otology & Neurotology
https://www.readbyqxmd.com/read/29099725/limitations-and-challenges-of-eit-based-monitoring-of-stroke-volume-and-pulmonary-artery-pressure
#12
Fabian Braun, Martin Proença, Mathieu Lemay, Mattia Bertschi, Andy Adler, Jean-Philippe Thiran, Josep Sola
<i>Objective</i>: Electrical impedance tomography (EIT) shows potential for radiation-free and non-invasive hemodynamic monitoring. However, many factors degrade the accuracy and repeatability of these measurements. Our goal is to estimate the impact of this variability on EIT-based monitoring of two important central hemodynamic parameters: stroke volume (SV) and pulmonary artery pressure (PAP). <i>Approach</i>: We performed simulations on a 4D (3D + t) bioimpedance model of a human volunteer to study the influence of four potential confounding factors (electrode belt displacement, electrode detachment, changes in hematocrit and lung air volume) on the performance of EIT-based SV and PAP estimation...
November 3, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/29060676/gamma-variate-modeling-of-indicator-dilution-curves-in-electrical-impedance-tomography
#13
Benjamin Hentze, Thomas Muders, Henning Luepschen, Steffen Leonhardt, Christian Putensen, Marian Walter
Electrical impedance tomography (EIT) is a non-invasive imaging technique, that can be used to monitor regional lung ventilation (V̇) in intensive care units (ICU) at bedside. This work introduces a method to extract regional lung perfusion (Q̇) from EIT image streams in order to quantify regional gas exchange in the lungs. EIT data from a single porcine animal trial, recorded during injection of a contrast agent (NaCl 10%) into a central venous catheter (CVC), are used for evaluation. Using semi-negative matrix factorization (Semi-NMF) a set of source signals is extracted from the data...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29060135/an-electrical-impedance-tomography-eit-multi-electrode-needle-probe-device-for-local-assessment-of-heterogeneous-tissue-impeditivity
#14
Davide Meroni, Camilla Carpano Maglioli, Dario Bovio, Francesco G Greco, Andrea Aliverti
Electrical Impedance Tomography (EIT) is an image reconstruction technique applied in medicine for the electrical imaging of living tissues. In literature there is the evidence that a large resistivity variation related to the differences of the human tissues exists. As a result of this interest for the electrical characterization of the biological samples, recently the attention is also focused on the identification and characterization of the human tissue, by studying the homogeneity of its structure. An 8 electrodes needle-probe device has been developed with the intent of identifying the structural inhomogeneities under the surface layers...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29059926/feasibility-study-of-imaging-fast-neural-activity-in-retinal-tissue-using-electrical-impedance-tomography
#15
Danyi Zhu, Xiunan Fang, Calvin Eiber, James Avery, David Holder, Alistair McEwan
Electrical Impedance Tomography has been recently applied to image fast neural activity in the somatosensory cerebral cortex. This non-invasive imaging modality has the unique advantage of high spatial-temporal resolution in millimeters over milliseconds. This work was designed to test an existing 32-channel EIT system, a modified UCL ScouseTom, and to discuss the feasibility of imaging neural activity in retinal tissue through computer simulation. The finite element method was used to model a retinal slice with a realistic conductivity-depth profile of the macaque eye...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29059883/monitoring-of-cardiac-output-and-lung-ventilation-by-electrical-impedance-tomography-in-a-porcine-model-of-acute-lung-injury
#16
Nadine Hochhausen, Henriette Dohmeier, Rolf Rossaint, Michael Czaplik
Adequate medical treatment of the Acute Respiratory Distress Syndrome is still challenging since patient-individual aspects have to be taken into account. Lung protective ventilation and hemodynamic stability have always been two of the most crucial aims of intensive care therapy. For both aspects, a continuous - preferably non-invasive - monitoring is desirable that is available at the bedside. Unfortunately, there is no technique clinically established yet, that provides both measurement of cardiac stroke volume and ventilation dynamics in real-time...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29059882/imaging-of-regional-air-distributions-in-porcine-lungs-using-high-performance-electrical-impedance-tomography-system
#17
G Y Jang, Y B Kim, H Wi, T I Oh, C R Chung, G Y Suh, E J Woo
Electrical impedance tomography (EIT) allows functional imaging of regional lung ventilation for real-time bedside monitoring of mechanically ventilated patients. Images showing time-changes of regional air distributions in the lungs can provide valuable diagnostic information for lung protective mechanical ventilation. This paper reports in vivo porcine imaging experiments of regional lung ventilation using a 16-channel parallel EIT system. Real-time time-difference chest images of 10 animals were reconstructed during mechanical ventilations with a temporal resolution of 50 frame/s...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29059834/electrical-properties-of-phantoms-for-mimicking-breast-tissue
#18
Vinicius G Sirtoli, Kaue Morcelles, Pedro Bertemes-Filho
In order to test and calibrate an EIT (Electrical Impedance Tomography) system, many researchers rely on phantoms mimicking breast tissues. These phantoms are usually made of saline solutions, agar and/or vegetables, allowing the user to set the conductivity of the material by changing the salt concentration. Due to that fact that the dispersion behavior in the vicinity of megahertz is fundamental to detect carcinoma, this work aims to propose a phantom composed by a mixture of agar and gelatin (emulating the normal tissue) and a piece of carrot (emulating the carcinoma)...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29059801/integration-of-piezo-capacitive-and-piezo-electric-nanoweb-based-pressure-sensors-for-imaging-of-static-and-dynamic-pressure-distribution
#19
Y J Jeong, T I Oh, E J Woo, K J Kim
Recently, highly flexible and soft pressure distribution imaging sensor is in great demand for tactile sensing, gait analysis, ubiquitous life-care based on activity recognition, and therapeutics. In this study, we integrate the piezo-capacitive and piezo-electric nanowebs with the conductive fabric sheets for detecting static and dynamic pressure distributions on a large sensing area. Electrical impedance tomography (EIT) and electric source imaging are applied for reconstructing pressure distribution images from measured current-voltage data on the boundary of the hybrid fabric sensor...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29045567/individualized-positive-end-expiratory-pressure-in-obese-patients-during-general-anaesthesia-a-randomized-controlled-clinical-trial-using-electrical-impedance-tomography
#20
C Nestler, P Simon, D Petroff, S Hammermüller, D Kamrath, S Wolf, A Dietrich, L M Camilo, A Beda, A R Carvalho, A Giannella-Neto, A W Reske, H Wrigge, Jonathan Thompson
Background: General anaesthesia leads to atelectasis, reduced end-expiratory lung volume (EELV), and diminished arterial oxygenation in obese patients. We hypothesized that a combination of a recruitment manoeuvre (RM) and individualized positive end-expiratory pressure (PEEP) can avoid these effects. Methods: Patients with a BMI ≥35 kg m -2 undergoing elective laparoscopic surgery were randomly allocated to mechanical ventilation with a tidal volume of 8 ml kg -1 predicted body weight and (i) an RM followed by individualized PEEP titrated using electrical impedance tomography (PEEP IND ) or (ii) no RM and PEEP of 5 cm H 2 O (PEEP 5 )...
December 1, 2017: British Journal of Anaesthesia
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