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electrical impedance tomography

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https://www.readbyqxmd.com/read/28086909/fast-detection-and-data-compensation-for-electrodes-disconnection-in-long-term-monitoring-of-dynamic-brain-electrical-impedance-tomography
#1
Ge Zhang, Meng Dai, Lin Yang, Weichen Li, Haoting Li, Canhua Xu, Xuetao Shi, Xiuzhen Dong, Feng Fu
BACKGROUND: Electrode disconnection is a common occurrence during long-term monitoring of brain electrical impedance tomography (EIT) in clinical settings. The data acquisition system suffers remarkable data loss which results in image reconstruction failure. The aim of this study was to: (1) detect disconnected electrodes and (2) account for invalid data. METHODS: Weighted correlation coefficient for each electrode was calculated based on the measurement differences between well-connected and disconnected electrodes...
January 7, 2017: Biomedical Engineering Online
https://www.readbyqxmd.com/read/28079607/mapping-regional-differences-of-local-pressure-volume-curves-with-electrical-impedance-tomography
#2
Alessandro Beda, Alysson R Carvalho, Nadja C Carvalho, Sören Hammermüller, Marcelo B P Amato, Thomas Muders, Claudia Gittel, Katharina Noreikat, Hermann Wrigge, Andreas W Reske
OBJECTIVES: Lung-protective mechanical ventilation aims to prevent alveolar collapse and overdistension, but reliable bedside methods to quantify them are lacking. We propose a quantitative descriptor of the shape of local pressure-volume curves derived from electrical impedance tomography, for computing maps that highlight the presence and location of regions of presumed tidal recruitment (i.e., elastance decrease during inflation, pressure-volume curve with upward curvature) or overdistension (i...
January 10, 2017: Critical Care Medicine
https://www.readbyqxmd.com/read/28076294/simulation-of-effects-of-the-electrode-structure-and-material-in-the-density-measuring-system-of-the-peripheral-nerve-based-on-micro-electrical-impedance-tomography
#3
Saber Behkami, Javad Frounchi, Firouz Ghaderi Pakdel, Thomas Stieglitz
The electrode structure in micro-electrical impedance tomography (MEIT) highly influences the measurement sensitivity and therefore the reconstructed image quality. Hence, optimizing the electrode structure leads to the improvement of image quality in the reconstruction procedure. Although there have been many investigations on electrical impedance tomography (EIT) electrodes, there is no comprehensive study on their influence on images of the peripheral nerve. In this paper, we present a simulation method to study the effects of the electrode structure in the density measurement system of the peripheral nerve based on MEIT...
January 11, 2017: Biomedizinische Technik. Biomedical Engineering
https://www.readbyqxmd.com/read/28068288/monitoring-of-breath-vocs-and-electrical-impedance-tomography-under-pulmonary-recruitment-in-mechanically-ventilated-patients
#4
Beate Brock, Svend Kamysek, Josephine Silz, Phillip Trefz, Jochen K Schubert, Wolfram Miekisch
Analysis of exhaled VOCs can provide information on physiology, metabolic processes, oxidative stress and lung diseases. In critically ill patients, VOC analysis may be used to gain complimentary information beyond global clinical parameters. This seems especially attractive in mechanically ventilated patients frequently suffering from impairment of gas exchange. This study was intended to assess (a) the effects of recruitment maneuvers onto VOC profiles, (b) the correlations between electrical impedance tomography (EIT) data and VOC profiles and (c) the effects of recruitment onto distribution of ventilation...
January 9, 2017: Journal of Breath Research
https://www.readbyqxmd.com/read/28055828/anisotropic-conductivity-tensor-imaging-of-in-vivo-canine-brain-using-dt-mreit
#5
Woo Chul Jeong, Saurav Z K Sajib, Nitish Katoch, Hyung Joong Kim, Oh In Kwon, Eung Je Woo
We present in vivo images of anisotropic electrical conductivity tensor distributions inside canine brains using diffusion tensor magnetic resonance electrical impedance tomography (DT-MREIT). The conductivity tensor is represented as a product of an ion mobility tensor and a scale factor of ion concentrations. Incorporating directional mobility information from water diffusion tensors, we developed a stable process to reconstruct anisotropic conductivity tensor images from measured magnetic flux density data using an MRI scanner...
January 2017: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28039243/electrical-impedance-tomography-for-non-invasive-assessment-of-stroke-volume-variation-in-health-and-experimental-lung-injury
#6
C J C Trepte, C Phillips, J Solà, A Adler, B Saugel, S Haas, S H Bohm, D A Reuter
BACKGROUND: Functional imaging by thoracic electrical impedance tomography (EIT) is a non-invasive approach to continuously assess central stroke volume variation (SVV) for guiding fluid therapy. The early available data were from healthy lungs without injury-related changes in thoracic impedance as a potentially influencing factor. The aim of this study was to evaluate SVV measured by EIT (SVVEIT) against SVV from pulse contour analysis (SVVPC) in an experimental animal model of acute lung injury at different lung volumes...
January 2017: British Journal of Anaesthesia
https://www.readbyqxmd.com/read/28012529/cone-beam-computed-tomography-in-children-with-cochlear-implants-the-effect-of-electrode-array-position-on-ecap
#7
Marine Lathuillière, Fanny Merklen, Jean-Pierre Piron, Marielle Sicard, Françoise Villemus, Nicolas Menjot de Champfleur, Frédéric Venail, Alain Uziel, Michel Mondain
OBJECTIVES: To assess the feasibility of using cone-beam computed tomography (CBCT) in young children with cochlear implants (CIs) and study the effect of intracochlear position on electrophysiological and behavioral measurements. METHODS: A total of 40 children with either unilateral or bilateral cochlear implants were prospectively included in the study. Electrode placement and insertion angles were studied in 55 Cochlear(®) implants (16 straight arrays and 39 perimodiolar arrays), using either CBCT or X-ray imaging...
January 2017: International Journal of Pediatric Otorhinolaryngology
https://www.readbyqxmd.com/read/28004642/linearity-of-electrical-impedance-tomography-during-maximum-effort-breathing-and-forced-expiration-maneuvers
#8
Chuong Ngo, Steffen Leonhardt, Tony Zhang, Markus Lüken, Berno Misgeld, Thomas Vollmer, Klaus Tenbrock, Sylvia Lehmann
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...
January 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28000769/characterization-of-blunt-chest-trauma-in-a-long-term-porcine-model-of-severe-multiple-trauma
#9
K Horst, T P Simon, R Pfeifer, M Teuben, K Almahmoud, Q Zhi, S Aguiar Santos, C Castelar Wembers, S Leonhardt, N Heussen, P Störmann, B Auner, B Relja, I Marzi, A T Haug, M van Griensven, M Kalbitz, M Huber-Lang, R Tolba, L K Reiss, S Uhlig, G Marx, H C Pape, F Hildebrand
Chest trauma has a significant relevance on outcome after severe trauma. Clinically, impaired lung function typically occurs within 72 hours after trauma. However, the underlying pathophysiological mechanisms are still not fully elucidated. Therefore, we aimed to establish an experimental long-term model to investigate physiological, morphologic and inflammatory changes, after severe trauma. Male pigs (sus scrofa) sustained severe trauma (including unilateral chest trauma, femur fracture, liver laceration and hemorrhagic shock)...
December 21, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27999152/optimizing-peep-by-electrical-impedance-tomography-in-a-porcine-animal-model-of-ards
#10
Nadine Hochhausen, Ingeborg Biener, Rolf Rossaint, Andreas Follmann, Christian Bleilevens, Till Braunschweig, Steffen Leonhardt, Michael Czaplik
BACKGROUND: Mechanical ventilation is necessary in diverse clinical circumstances. Especially in the context of ARDS, so-called protective ventilation strategies must be followed. It is already known that PEEP might enhance oxygenation in ARDS. However, determining the optimal PEEP settings in clinical routines is challenging. Electrical impedance tomography (EIT) is a promising technique with which to adjust ventilator settings. We investigated whether the combination of different EIT parameters, namely the global inhomogeneity and hyperdistension indices, may lead to a feasible and safe PEEP setting...
December 20, 2016: Respiratory Care
https://www.readbyqxmd.com/read/27997805/physiologic-effects-of-high-flow-nasal-cannula-in-acute-hypoxemic-respiratory-failure
#11
Tommaso Mauri, Cecilia Turrini, Nilde Eronia, Giacomo Grasselli, Carlo Alberto Volta, Giacomo Bellani, Antonio Pesenti
RATIONALE: High-flow nasal cannula (HFNC) improves the clinical outcomes of non-intubated acute hypoxemic respiratory failure (AHRF) patients. OBJECTIVES: To assess the effects of HFNC on gas exchange, inspiratory effort, minute ventilation, end-expiratory lung volume, dynamic compliance and ventilation homogeneity in AHRF patients. METHODS: This was a prospective randomized cross-over study in non-intubated AHRF patients with PaO2/setFiO2 ≤300 mmHg admitted to the Intensive Care Unit...
December 20, 2016: American Journal of Respiratory and Critical Care Medicine
https://www.readbyqxmd.com/read/27932671/coupling-of-eit-with-computational-lung-modeling-for-predicting-patient-specific-ventilatory-responses
#12
Christian J Roth, Tobias Becher, Inez Frerichs, Norbert Weiler, Wolfgang A Wall
Providing personalised optimal mechanical ventilation for patients with acute or chronic respiratory failure is still a challenge within a clinical setting for each case anew. In this article, we integrate electrical impedance tomography (EIT) monitoring into a powerful patient-specific computational lung model to create an approach for personalising protective ventilatory treatment. The underlying computational lung model is able to predict global quantities e.g., tracheal flow and tidal volume, as well as local tissue aeration and strains for any ventilation manoeuvre...
December 8, 2016: Journal of Applied Physiology
https://www.readbyqxmd.com/read/27910465/accelerated-reconstruction-of-electrical-impedance-tomography-images-via-patch-based-sparse-representation
#13
Qi Wang, Zhijie Lian, Jianming Wang, Qingliang Chen, Yukuan Sun, Xiuyan Li, Xiaojie Duan, Ziqiang Cui, Huaxiang Wang
Electrical impedance tomography (EIT) reconstruction is a nonlinear and ill-posed problem. Exact reconstruction of an EIT image inverts a high dimensional mathematical model to calculate the conductivity field, which causes significant problems regarding that the computational complexity will reduce the achievable frame rate, which is considered as a major advantage of EIT imaging. The single-step method, state estimation method, and projection method were always used to accelerate reconstruction process. The basic principle of these methods is to reduce computational complexity...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27906709/looking-closer-at-acute-respiratory-distress-syndrome-the-role-of-advanced-imaging-techniques
#14
Giacomo Bellani, Jean-Jaques Rouby, Jean-Michel Constantin, Antonio Pesenti
PURPOSE OF REVIEW: Advanced imaging techniques have provided invaluable insights in understanding of acute respiratory distress syndrome (ARDS) and the effect of therapeutic strategies, thanks to the possibility of gaining regional information and moving from simple 'anatomical' information to in-vivo functional imaging. RECENT FINDINGS: Computed tomography (CT) led to the understanding of several ARDS mechanisms and interaction with mechanical ventilation. It is nowadays frequently part of routine diagnostic workup, often leading to treatment changes...
February 2017: Current Opinion in Critical Care
https://www.readbyqxmd.com/read/27897152/a-novel-multi-frequency-electrical-impedance-tomography-spectral-imaging-algorithm-for-early-stroke-detection
#15
Lin Yang, Canhua Xu, Meng Dai, Feng Fu, Xuetao Shi, Xiuzhen Dong
Multi-frequency electrical impedance tomography (MFEIT) reconstructs the image of conductivity inside the human body based on the dependence of tissue conductivity on frequency. As there exist differences in the conductivity over frequency between blood, ischemic cortical tissue and normal cortical tissue, MFEIT has potential application in the detection of acute stroke. However, because the conductivity distribution of the human head is highly inhomogeneous and the conductivities of normal head tissue and stroke lesion tissue both change with frequency, the anomaly and normal head tissues are often mixed together in the reconstructed image, which makes it difficult to discern the anomaly...
December 2016: Physiological Measurement
https://www.readbyqxmd.com/read/27881405/effectiveness-of-individualized-lung-recruitment-strategies-at-birth-an-experimental-study-in-preterm-lambs
#16
David G Tingay, Anushi Rajapaksa, Emanuela Zannin, Prue M Pereira-Fantini, Raffaele L Dellaca, Elizabeth J Perkins, Cornelis E E Zonneveld, Andy Adler, Don Black, Inéz Frerichs, Anna Lavizzari, Magdy Sourial, Bartłomiej Grychtol, Fabio Mosca, Peter G Davis
Respiratory transition at birth involves rapidly clearing fetal lung liquid and preventing efflux back into the lung while aeration is established. We have developed a sustained inflation (SIOPT) individualized to volume response and a dynamic tidal positive end-expiratory pressure (PEEP) (open lung volume, OLV) strategy that both enhance this process. We aimed to compare the effect of each with a group managed with PEEP of 8 cmH2O and no recruitment maneuver (No-RM), on gas exchange, lung mechanics, spatiotemporal aeration, and lung injury in 127 ± 1 day preterm lambs...
January 1, 2017: American Journal of Physiology. Lung Cellular and Molecular Physiology
https://www.readbyqxmd.com/read/27878858/non-invasive-tools-for-the-diagnosis-of-cutaneous-melanoma
#17
REVIEW
C Fink, H A Haenssle
BACKGROUND: While the excisional biopsy and histological examination of suspicious lesions remains the current gold standard for diagnosing cutaneous melanoma (CM), there is a demand for more objective and non-invasive examination methods that may support clinicians in their decision when to biopsy or not. METHODS: This review is based on publications and guidelines retrieved by a selective search in PubMed and MEDLINE and focused on non-invasive diagnostic strategies for detecting melanoma...
November 22, 2016: Skin Research and Technology
https://www.readbyqxmd.com/read/27871877/journal-allergy-clinical-immunology-perspective-clinical-potential-for-imaging-in-asthma-and-other-lung-disorders
#18
Emily M DeBoer, David R Spielberg, Alan S Brody
The ability of lung imaging to phenotype patients, determine prognosis, and to predict response to treatments is expanding in clinical and translational research. The purpose of this perspective is to describe current imaging modalities that may be useful clinical tools in asthma and other lung disorders and to explore some of the new developments in imaging modalities of the lung. These imaging modalities include chest radiography (CXR), computed tomography (CT), lung magnetic resonance imaging (MRI), electrical impedance tomography (EIT), bronchoscopy, and others...
November 18, 2016: Journal of Allergy and Clinical Immunology
https://www.readbyqxmd.com/read/27869707/ex-vivo-characterization-of-bioimpedance-spectroscopy-of-normal-ischemic-and-hemorrhagic-rabbit-brain-tissue-at-frequencies-from-10-hz-to-1-mhz
#19
Lin Yang, Ge Zhang, Jiali Song, Meng Dai, Canhua Xu, Xiuzhen Dong, Feng Fu
Stroke is a severe cerebrovascular disease and is the second greatest cause of death worldwide. Because diagnostic tools (CT and MRI) to detect acute stroke cannot be used until the patient reaches the hospital setting, a portable diagnostic tool is urgently needed. Because biological tissues have different impedance spectra under normal physiological conditions and different pathological states, multi-frequency electrical impedance tomography (MFEIT) can potentially detect stroke. Accurate impedance spectra of normal brain tissue (gray and white matter) and stroke lesions (ischemic and hemorrhagic tissue) are important elements when studying stroke detection with MFEIT...
November 18, 2016: Sensors
https://www.readbyqxmd.com/read/27854325/a-deformable-smart-skin-for-continuous-sensing-based-on-electrical-impedance-tomography
#20
Francesco Visentin, Paolo Fiorini, Kenji Suzuki
In this paper, we present a low-cost, adaptable, and flexible pressure sensor that can be applied as a smart skin over both stiff and deformable media. The sensor can be easily adapted for use in applications related to the fields of robotics, rehabilitation, or costumer electronic devices. In order to remove most of the stiff components that block the flexibility of the sensor, we based the sensing capability on the use of a tomographic technique known as Electrical Impedance Tomography. The technique allows the internal structure of the domain under study to be inferred by reconstructing its conductivity map...
November 16, 2016: Sensors
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