scholarly journals Electrode positioning to investigate the changes of the thoracic bioimpedance caused by aortic dissection – a simulation study

2020 ◽  
Vol 11 (1) ◽  
pp. 38-48
Author(s):  
V. Badeli ◽  
G. M. Melito ◽  
A. Reinbacher-Köstinger ◽  
O. Bíró ◽  
K. Ellermann
Keyword(s):  
Aortic Dissection ◽  
Simulation Model ◽  
Impedance Cardiography ◽  
Patient Specific ◽  
Non Invasive ◽  
Impedance Cardiogram ◽  
Aortic Pathology ◽  
Invasive Method ◽  
Electrode Positioning ◽  
Transthoracic Electrical Impedance

AbstractImpedance cardiography (ICG) is a non-invasive method to evaluate several cardiodynamic parameters by measuring the cardiac-synchronous changes in the dynamic transthoracic electrical impedance. ICG allows us to identify and quantify conductivity changes inside the thorax by measuring the impedance on the thorax during a cardiac cycle. Pathologic changes in the aorta, like aortic dissection, will alter the aortic shape as well as the blood flow and consequently, the impedance cardiogram. This fact distorts the evaluated cardiodynamic parameters, but it could lead to the possibility to identify aortic pathology. A 3D numerical simulation model is used to compute the impedance changes on the thorax surface in case of the type B aortic dissection. A sensitivity analysis is applied using this simulation model to investigate the suitability of different electrode configurations considering several patient-specific cases. Results show that the remarkable pathological changes in the aorta caused by aortic dissection alters the impedance cardiogram significantly.

scholarly journals Echocardiography diagnosis of pregnancy with aortic dissection: a case report

2020 ◽  
Author(s):  
Jing Wang ◽  
Anlong Wang ◽  
Jian Zhang ◽  
Chunjie Hou
Keyword(s):  
Aortic Dissection ◽  
False Lumen ◽  
Clinical Manifestations ◽  
Late Pregnancy ◽  
Clinical Value ◽  
Case Presentation ◽  
Non Invasive ◽  
Mortality Case ◽  
Invasive Method ◽  
Diagnosis Accuracy

Abstract Background: We report a case of 34 weeks + gestation with aortic dissection to explore the diagnosis and treatment of this type of pregnant woman and to reduce maternal mortality. Case presentation: This report describes the clinical manifestations of a case of late pregnancy with acute aortic dissection (Stanford A Type). Echocardiography was used to detect the location of the rupture, the extent of exfoliation, the true and false lumen, the presence or absence of thrombus in the false lumen, the degree of aortic regurgitation, etc. After the diagnosis, the patients received surgical treatment as soon as possible. The detection rate and type diagnosis accuracy of ultrasonography for pregnancy complicated with aortic dissection are reliable. The location of the intimal rupture by ultrasound was consistent with the intraoperative findings, and there were no recent complications in the mother and newborn. Conclusion: The third trimester of pregnancy with aortic dissection is dangerous. As a simple, safe and non-invasive method, echocardiography has high clinical value in the diagnosis of pregnant patients with aortic dissection.

scholarly journals Cross-Entropy Learning for Aortic Pathology Classification of Artificial Multi-Sensor Impedance Cardiography Signals

Entropy ◽  
2021 ◽  
Vol 23 (12) ◽  
pp. 1661
Author(s):  
Tobias Spindelböck ◽  
Sascha Ranftl ◽  
Wolfgang von der Linden
Keyword(s):  
Blood Flow ◽  
Aortic Dissection ◽  
Network Architecture ◽  
Impedance Cardiography ◽  
False Lumen ◽  
Flow Characteristics ◽  
Virtual Patient ◽  
Cross Entropy ◽  
Aortic Pathology ◽  
Aortic Dissections

An aortic dissection, a particular aortic pathology, occurs when blood pushes through a tear between the layers of the aorta and forms a so-called false lumen. Aortic dissection has a low incidence compared to other diseases, but a relatively high mortality that increases with disease progression. An early identification and treatment increases patients’ chances of survival. State-of-the-art medical imaging techniques have several disadvantages; therefore, we propose the detection of aortic dissections through their signatures in impedance cardiography signals. These signatures arise due to pathological blood flow characteristics and a blood conductivity that strongly depends on the flow field, i.e., the proposed method is, in principle, applicable to any aortic pathology that changes the blood flow characteristics. For the signal classification, we trained a convolutional neural network (CNN) with artificial impedance cardiography data based on a simulation model for a healthy virtual patient and a virtual patient with an aortic dissection. The network architecture was tailored to a multi-sensor, multi-channel time-series classification with a categorical cross-entropy loss function as the training objective. The trained network typically yielded a specificity of (93.9±0.1)% and a sensitivity of (97.5±0.1)%. A study of the accuracy as a function of the size of an aortic dissection yielded better results for a small false lumen with larger noise, which emphasizes the question of the feasibility of detecting aortic dissections in an early state.

scholarly journals Bayesian inference of multi-sensors impedance cardiography for detection of aortic dissection

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Vahid Badeli ◽  
Sascha Ranftl ◽  
Gian Marco Melito ◽  
Alice Reinbacher-Köstinger ◽  
Wolfgang Von Der Linden ◽  
...  
Keyword(s):  
Probability Theory ◽  
Bayesian Inference ◽  
Aortic Dissection ◽  
Electrical Impedance ◽  
Impedance Cardiography ◽  
Bayesian Probability ◽  
Content Type ◽  
Non Invasive ◽  
Life Threatening ◽  
Relevant Domain

Purpose This paper aims to introduce a non-invasive and convenient method to detect a life-threatening disease called aortic dissection. A Bayesian inference based on enhanced multi-sensors impedance cardiography (ICG) method has been applied to classify signals from healthy and sick patients. Design/methodology/approach A 3D numerical model consisting of simplified organ geometries is used to simulate the electrical impedance changes in the ICG-relevant domain of the human torso. The Bayesian probability theory is used for detecting an aortic dissection, which provides information about the probabilities for both cases, a dissected and a healthy aorta. Thus, the reliability and the uncertainty of the disease identification are found by this method and may indicate further diagnostic clarification. Findings The Bayesian classification shows that the enhanced multi-sensors ICG is more reliable in detecting aortic dissection than conventional ICG. Bayesian probability theory allows a rigorous quantification of all uncertainties to draw reliable conclusions for the medical treatment of aortic dissection. Originality/value This paper presents a non-invasive and reliable method based on a numerical simulation that could be beneficial for the medical management of aortic dissection patients. With this method, clinicians would be able to monitor the patient’s status and make better decisions in the treatment procedure of each patient.

scholarly journals A Combined In Vivo, In Vitro, In Silico Approach for Patient-Specific Haemodynamic Studies of Aortic Dissection

2020 ◽  
Vol 48 (12) ◽  
pp. 2950-2964
Author(s):  
Mirko Bonfanti ◽  
Gaia Franzetti ◽  
Shervanthi Homer-Vanniasinkam ◽  
Vanessa Díaz-Zuccarini ◽  
Stavroula Balabani
Keyword(s):  
Aortic Dissection ◽  
In Silico ◽  
Clinical Decision ◽  
Patient Specific ◽  
Type B ◽  
Non Invasive ◽  
Cfd Models ◽  
Numerical Predictions

AbstractThe optimal treatment of Type-B aortic dissection (AD) is still a subject of debate, with up to 50% of the cases developing late-term complications requiring invasive intervention. A better understanding of the patient-specific haemodynamic features of AD can provide useful insights on disease progression and support clinical management. In this work, a novel in vitro and in silico framework to perform personalised studies of AD, informed by non-invasive clinical data, is presented. A Type-B AD was investigated in silico using computational fluid dynamics (CFD) and in vitro by means of a state-of-the-art mock circulatory loop and particle image velocimetry (PIV). Both models not only reproduced the anatomical features of the patient, but also imposed physiologically-accurate and personalised boundary conditions. Experimental flow rate and pressure waveforms, as well as detailed velocity fields acquired via PIV, are extensively compared against numerical predictions at different locations in the aorta, showing excellent agreement. This work demonstrates how experimental and numerical tools can be developed in synergy to accurately reproduce patient-specific AD blood flow. The combined platform presented herein constitutes a powerful tool for advanced haemodynamic studies for a range of vascular conditions, allowing not only the validation of CFD models, but also clinical decision support, surgical planning as well as medical device innovation.

scholarly journals Contactless Impedance Cardiography Using Embedded Sensors

2013 ◽  
Vol 13 (3) ◽  
pp. 157-164 ◽  
Author(s):  
E. Pinheiro ◽  
O. Postolache ◽  
P. Girão
Keyword(s):  
Cardiac Output ◽  
Impedance Cardiography ◽  
Left Ventricular ◽  
Embedded Sensors ◽  
Left Ventricular Ejection ◽  
Ejection Time ◽  
Left Ventricular Ejection Time ◽  
Non Invasive ◽  
Impedance Cardiogram ◽  
Ventricular Ejection Time

Impedance cardiography is a technique developed with the intent of monitoring cardiac output. By inspecting a few properties of the obtained signal (impedance cardiogram (ICG), the left ventricular ejection time can be derived with certainty, and an estimate of cardiac output is available. This signal is nowadays used in non-invasive monitoring, requiring the placement of electrodes over the subject’s skin, either ECG-type or in the form of encircling bands. The work here reported describes the implementation steps and the results obtained when embedding the ICG circuitry in a wheelchair’s backrest. The subject is seated normally, is normally dressed, and is completely unaware that monitoring is taking place. That means that the variation of tenths of ohm produced due to the cardiac cycle has to be detected with electrodes having substantial coupling impedance. Contactless ICG with embedded sensors was developed and tested on fourteen healthy subjects. The signal was always acquired, although respiratory activity is also important, constituting a noteworthy innovation in the area.

scholarly journals Linking Aortic Mechanical Properties, Gene Expression and Microstructure: A New Perspective on Regional Weakening in Abdominal Aortic Aneurysms

2021 ◽  
Vol 8 ◽  
Author(s):  
Arianna Forneris ◽  
Jacob Kennard ◽  
Alina Ismaguilova ◽  
Robert D. Shepherd ◽  
Deborah Studer ◽  
...  
Keyword(s):  
Gene Expression ◽  
Clinical Decision Making ◽  
Fluid Dynamic ◽  
Abdominal Aortic Aneurysms ◽  
Aortic Aneurysms ◽  
Patient Specific ◽  
Tissue Samples ◽  
Non Invasive ◽  
Abdominal Aortic ◽  
Aortic Pathology

Background: Current clinical practice for the assessment of abdominal aortic aneurysms (AAA) is based on vessel diameter and does not account for the multifactorial, heterogeneous remodeling that results in the regional weakening of the aortic wall leading to aortic growth and rupture. The present study was conducted to determine correlations between a novel non-invasive surrogate measure of regional aortic weakening and the results from invasive analyses performed on corresponding ex vivo aortic samples. Tissue samples were evaluated to classify local wall weakening and the likelihood of further degeneration based on non-invasive indices.Methods: A combined, image-based fluid dynamic and in-vivo strain analysis approach was used to estimate the Regional Aortic Weakness (RAW) index and assess individual aortas of AAA patients prior to elective surgery. Nine patients were treated with complete aortic resection allowing the systematic collection of tissue samples that were used to determine regional aortic mechanics, microstructure and gene expression by means of mechanical testing, microscopy and transcriptomic analyses.Results: The RAW index was significantly higher for samples exhibiting lower mechanical strength (p = 0.035) and samples classified as low elastin content (p = 0.020). Samples with higher RAW index had the greatest number of genes differentially expressed compared to any constitutive metric. High RAW samples showed a decrease in gene expression for elastin and a down-regulation of pathways responsible for cell movement, reorganization of cytoskeleton, and angiogenesis.Conclusions: This work describes the first AAA index free of assumptions for material properties and accounting for patient-specific mechanical behavior in relation to aneurysm strength. Use of the RAW index captured biomechanical changes linked to the weakening of the aorta and revealed changes in microstructure and gene expression. This approach has the potential to provide an improved tool to aid clinical decision-making in the management of aortic pathology.

Malfunctional Reorganization in the Developing Limbo-Prefrontal System in Animals: Implications for Human Psychoses?

2001 ◽  
Vol 12 (1) ◽  
pp. 8-14
Author(s):  
Gertraud Teuchert-Noodt ◽  
Ralf R. Dawirs
Keyword(s):  
Prefrontal Cortex ◽  
Mental Disorders ◽  
Dentate Gyrus ◽  
Cognitive Functions ◽  
Experimental Approach ◽  
Regulatory Mechanisms ◽  
Hippocampal Dentate Gyrus ◽  
Non Invasive ◽  
Invasive Method ◽  
Activity Dependent

Abstract: Neuroplasticity research in connection with mental disorders has recently bridged the gap between basic neurobiology and applied neuropsychology. A non-invasive method in the gerbil (Meriones unguiculus) - the restricted versus enriched breading and the systemically applied single methamphetamine dose - offers an experimental approach to investigate psychoses. Acts of intervening affirm an activity dependent malfunctional reorganization in the prefrontal cortex and in the hippocampal dentate gyrus and reveal the dopamine position as being critical for the disruption of interactions between the areas concerned. From the extent of plasticity effects the probability and risk of psycho-cognitive development may be derived. Advance may be expected from insights into regulatory mechanisms of neurogenesis in the hippocampal dentate gyrus which is obviously to meet the necessary requirements to promote psycho-cognitive functions/malfunctions via the limbo-prefrontal circuit.

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