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723 results on '"CORSI, CRISTIANA"'

2. Reconstruction of Potassium Concentrations with the ECG on Imbalanced Datasets

Author

Pilia, Nicolas, Corsi, Cristiana, Severi, Stefano, Dössel, Olaf, and Loewe, Axel

Subjects
Electrical Engineering and Systems Science - Signal Processing
Abstract

End-stage chronic kidney disease (CKD) patients are facing a 30% rise for the risk of lethal cardiac events (LCE) compared to non-CKD patients. At the same time, these patients undergoing dialysis experience shifts in the potassium concentrations. The increased risk of LCE paired with the concentration changes suggest a connection between LCE and concentration disbalances. To prove this link, a continuous monitoring device for the ionic concentrations, e.g. the ECG, is needed. In this work, we want to answer if an optimised signal processing chain can improve the result quantify the influence of a disbalanced training dataset on the final estimation result. The study was performed on a dataset consisting of 12-lead ECGs recorded during dialysis sessions of 32 patients. We selected three features to find a mapping from ECG features to [K+]o: T-wave ascending slope, T-wave descending slope and T-wave amplitude. A polynomial model of 3rd order was used to reconstruct the concentrations from these features. We solved a regularised weighted least squares problem with a weighting matrix dependent on the frequency of each concentration in the dataset (frequent concentration weighted less). By doing so, we tried to generate a model being suitable for the whole range of the concentrations.With weighting, errors are increasing for the whole dataset. For the data partition with [K+]o<5 mmol/l, errors are increasing, for [K+]o$\geq$5 mmol/l, errors are decreasing. However, and apart from the exact reconstruction results, we can conclude that a model being valid for all patients and not only the majority, needs to be learned with a more homogeneous dataset. This can be achieved by leaving out data points or by weighting the errors during the model fitting. With increasing weighting, we increase the performance on the part of the [K+]o that are less frequent which was desired in our case., Comment: Non-peer-reviewed submission to "Workshop Biosignale 2020" Kiel; 2-page paper-like abstract

Published
2020

3. A Global Benchmark of Algorithms for Segmenting Late Gadolinium-Enhanced Cardiac Magnetic Resonance Imaging

Author

Xiong, Zhaohan, Xia, Qing, Hu, Zhiqiang, Huang, Ning, Bian, Cheng, Zheng, Yefeng, Vesal, Sulaiman, Ravikumar, Nishant, Maier, Andreas, Yang, Xin, Heng, Pheng-Ann, Ni, Dong, Li, Caizi, Tong, Qianqian, Si, Weixin, Puybareau, Elodie, Khoudli, Younes, Geraud, Thierry, Chen, Chen, Bai, Wenjia, Rueckert, Daniel, Xu, Lingchao, Zhuang, Xiahai, Luo, Xinzhe, Jia, Shuman, Sermesant, Maxime, Liu, Yashu, Wang, Kuanquan, Borra, Davide, Masci, Alessandro, Corsi, Cristiana, de Vente, Coen, Veta, Mitko, Karim, Rashed, Preetha, Chandrakanth Jayachandran, Engelhardt, Sandy, Qiao, Menyun, Wang, Yuanyuan, Tao, Qian, Nunez-Garcia, Marta, Camara, Oscar, Savioli, Nicolo, Lamata, Pablo, and Zhao, Jichao

Subjects
Computer Science - Computer Vision and Pattern Recognition, Computer Science - Machine Learning, Electrical Engineering and Systems Science - Image and Video Processing, Statistics - Machine Learning
Abstract

Segmentation of cardiac images, particularly late gadolinium-enhanced magnetic resonance imaging (LGE-MRI) widely used for visualizing diseased cardiac structures, is a crucial first step for clinical diagnosis and treatment. However, direct segmentation of LGE-MRIs is challenging due to its attenuated contrast. Since most clinical studies have relied on manual and labor-intensive approaches, automatic methods are of high interest, particularly optimized machine learning approaches. To address this, we organized the "2018 Left Atrium Segmentation Challenge" using 154 3D LGE-MRIs, currently the world's largest cardiac LGE-MRI dataset, and associated labels of the left atrium segmented by three medical experts, ultimately attracting the participation of 27 international teams. In this paper, extensive analysis of the submitted algorithms using technical and biological metrics was performed by undergoing subgroup analysis and conducting hyper-parameter analysis, offering an overall picture of the major design choices of convolutional neural networks (CNNs) and practical considerations for achieving state-of-the-art left atrium segmentation. Results show the top method achieved a dice score of 93.2% and a mean surface to a surface distance of 0.7 mm, significantly outperforming prior state-of-the-art. Particularly, our analysis demonstrated that double, sequentially used CNNs, in which a first CNN is used for automatic region-of-interest localization and a subsequent CNN is used for refined regional segmentation, achieved far superior results than traditional methods and pipelines containing single CNNs. This large-scale benchmarking study makes a significant step towards much-improved segmentation methods for cardiac LGE-MRIs, and will serve as an important benchmark for evaluating and comparing the future works in the field.

Published
2020

4. A detailed mathematical model of the human atrial cardiomyocyte: integration of electrophysiology and cardiomechanics.

Author

Mazhar, Fazeelat, Bartolucci, Chiara, Regazzoni, Francesco, Paci, Michelangelo, Dedè, Luca, Quarteroni, Alfio, Corsi, Cristiana, and Severi, Stefano

Subjects
MATHEMATICAL models, HEART cells, ATRIAL fibrillation, ELECTROPHYSIOLOGY, PHOSPHORYLATION
Abstract

Mechano‐electric regulations (MER) play an important role in the maintenance of cardiac performance. Mechano‐calcium and mechano‐electric feedback (MCF and MEF) pathways adjust the cardiomyocyte contractile force according to mechanical perturbations and affects electro‐mechanical coupling. MER integrates all these regulations in one unit resulting in a complex phenomenon. Computational modelling is a useful tool to accelerate the mechanistic understanding of complex experimental phenomena. We have developed a novel model that integrates the MER loop for human atrial cardiomyocytes with proper consideration of feedforward and feedback pathways. The model couples a modified version of the action potential (AP) Koivumäki model with the contraction model by Quarteroni group. The model simulates iso‐sarcometric and isometric twitches and the feedback effects on AP and Ca2+‐handling. The model showed a biphasic response of Ca2+ transient (CaT) peak to increasing pacing rates and highlights the possible mechanisms involved. The model has shown a shift of the threshold for AP and CaT alternans from 4.6 to 4 Hz under post‐operative atrial fibrillation, induced by depressed SERCA activity. The alternans incidence was dependent on a chain of mechanisms including RyRs availability time, MCF coupling, CaMKII phosphorylation, and the stretch levels. As a result, the model predicted a 10% slowdown of conduction velocity for a 20% stretch, suggesting a role of stretch in creation of substrate formation for atrial fibrillation. Overall, we conclude that the developed model provides a physiological CaT followed by a physiological twitch. This model can open pathways for the future studies of human atrial electromechanics. Key points: With the availability of human atrial cellular data, interest in atrial‐specific model integration has been enhanced.We have developed a detailed mathematical model of human atrial cardiomyocytes including the mechano‐electric regulatory loop. The model has gone through calibration and evaluation phases against a wide collection of available human in‐vitro data.The usefulness of the model for analysing clinical problems has been preliminaryly tested by simulating the increased incidence of Ca2+ transient and action potential alternans at high rates in post‐operative atrial fibrillation condition.The model determines the possible role of mechano‐electric feedback in alternans incidence, which can increase vulnerability to atrial arrhythmias by varying stretch levels.We found that our physiologically accurate description of Ca2+ handling can reproduce many experimental phenomena and can help to gain insights into the underlying pathophysiological mechanisms. [ABSTRACT FROM AUTHOR]

Published
2024
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6. Noninvasive quantification of blood potassium concentration from ECG in hemodialysis patients

Author

Corsi, Cristiana, Cortesi, Marilisa, Callisesi, Giulia, De Bie, Johan, Napolitano, Carlo, Santoro, Antonio, Mortara, David, and Severi, Stefano

Subjects
Biomedical and Clinical Sciences, Engineering, Biomedical Engineering, Bioengineering, Clinical Research, Adolescent, Adult, Child, Electrocardiography, Female, Humans, Long QT Syndrome, Male, Middle Aged, Potassium, Renal Dialysis, Young Adult
Abstract

Blood potassium concentration ([K+]) influences the electrocardiogram (ECG), particularly T-wave morphology. We developed a new method to quantify [K+] from T-wave analysis and tested its clinical applicability on data from dialysis patients, in whom [K+] varies significantly during the therapy. To elucidate the mechanism linking [K+] and T-wave, we also analysed data from long QT syndrome type 2 (LQT2) patients, testing the hypothesis that our method would have underestimated [K+] in these patients. Moreover, a computational model was used to explore the physiological processes underlying our estimator at the cellular level. We analysed 12-lead ECGs from 45 haemodialysis and 12 LQT2 patients. T-wave amplitude and downslope were calculated from the first two eigenleads. The T-wave slope-to-amplitude ratio (TS/A) was used as starting point for an ECG-based [K+] estimate (KECG). Leave-one-out cross-validation was performed. Agreement between KECG and reference [K+] from blood samples was promising (error: -0.09 ± 0.59 mM, absolute error: 0.46 ± 0.39 mM). The analysis on LQT2 patients, also supported by the outcome of computational analysis, reinforces our interpretation that, at the cellular level, delayed-rectifier potassium current is a main contributor of KECG correlation to blood [K+]. Following a comprehensive validation, this method could be effectively applied to monitor patients at risk for hyper/hypokalemia.

Published
2017

8. A Semantic-Wise Convolutional Neural Network Approach for 3-D Left Atrium Segmentation from Late Gadolinium Enhanced Magnetic Resonance Imaging

Author

Borra, Davide, Masci, Alessandro, Esposito, Lorena, Andalò, Alice, Fabbri, Claudio, Corsi, Cristiana, Hutchison, David, Series Editor, Kanade, Takeo, Series Editor, Kittler, Josef, Series Editor, Kleinberg, Jon M., Series Editor, Mattern, Friedemann, Series Editor, Mitchell, John C., Series Editor, Naor, Moni, Series Editor, Pandu Rangan, C., Series Editor, Steffen, Bernhard, Series Editor, Terzopoulos, Demetri, Series Editor, Tygar, Doug, Series Editor, Pop, Mihaela, editor, Sermesant, Maxime, editor, Zhao, Jichao, editor, Li, Shuo, editor, McLeod, Kristin, editor, Young, Alistair, editor, Rhode, Kawal, editor, and Mansi, Tommaso, editor

Published
2019
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12. A Patient-Specific Computational Fluid Dynamics Model of the Left Atrium in Atrial Fibrillation: Development and Initial Evaluation

Author

Masci, Alessandro, Alessandrini, Martino, Forti, Davide, Menghini, Filippo, Dedé, Luca, Tommasi, Corrado, Quarteroni, Alfio, Corsi, Cristiana, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Weikum, Gerhard, Series editor, Pop, Mihaela, editor, and Wright, Graham A, editor

Published
2017
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25. Supervised Learning Modelization and Segmentation of Cardiac Scar in Delayed Enhanced MRI

Author

Lara, Laura, Vera, Sergio, Perez, Frederic, Lanconelli, Nico, Morisi, Rita, Donini, Bruno, Turco, Dario, Corsi, Cristiana, Lamberti, Claudio, Gavidia, Giovana, Bordone, Maurizio, Soudah, Eduardo, Curzen, Nick, Rosengarten, James, Morgan, John, Herrero, Javier, González Ballester, Miguel A., Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Camara, Oscar, editor, Mansi, Tommaso, editor, Pop, Mihaela, editor, Rhode, Kawal, editor, Sermesant, Maxime, editor, and Young, Alistair, editor

Published
2013
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26. Innovative Solutions in Health Monitoring at Home: The Real-Time Assessment of Serum Potassium Concentration from ECG

Author

Corsi, Cristiana, De Bie, Johan, Mortara, David, Severi, Stefano, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Donnelly, Mark, editor, Paggetti, Cristiano, editor, Nugent, Chris, editor, and Mokhtari, Mounir, editor

Published
2012
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29. PO-02-078 STANDARDIZED REGIONALIZATION OF THE ATRIA FOR 3D CARDIAC IMAGING, ELECTROANATOMICAL MAPPING AND COMPUTATIONAL MODELING – A MULTIDISCIPLINARY CONSENSUS OF THE PERSONALIZEAF CONSORTIUM

Author

Goetz, Christian, Martinez, Lourdes M., Invers-Rubio, Eric, Hussain, Sachal, Mont, Lluis, Schmidt, Constanze, Corsi, Cristiana, Doessel, Olaf, Climent, Andreu M., Rodriguez, Blanca, Schotten, Ulrich, Cabrera, Jose A., Loewe, Axel, Guillem, Maria S., and Althoff, Till F.

Published
2024
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31. Computational Analysis of Mapping Catheter Geometry and Contact Quality Effects on Rotor Detection in Atrial Fibrillation

Author

Bartolucci, Chiara, Fabbri, Claudio, Tomasi, Corrado, Sabbatani, Paolo, Severi, Stefano, Corsi, Cristiana, Bartolucci C., Fabbri C., Tomasi C., Sabbatani P., Severi S., and Corsi C.

Subjects
computational modeling, synthetic electrograms, Physiology, Physiology (medical), rotor detection, QP1-981, atrial fibrillation, mapping catheter geometry, cathether ablation, Original Research
Abstract

Atrial fibrillation (AF) is the most common cardiac arrhythmia and catheter mapping has been proved to be an effective approach for detecting AF drivers to be targeted by ablation. Among drivers, the so-called rotors have gained the most attention: their identification and spatial location could help to understand which patient-specific mechanisms are acting, and thus to guide the ablation execution. Since rotor detection by multi-electrode catheters may be influenced by several structural parameters including inter-electrode spacing, catheter coverage, and endocardium-catheter distance, in this study we proposed a tool for testing the ability of different catheter shapes to detect rotors in different conditions. An approach based on the solution of the monodomain equations coupled with a modified Courtemanche ionic atrial model, that considers an electrical remodeling, was applied to simulate spiral wave dynamics on a 2D model for 7.75 s. The developed framework allowed the acquisition of unipolar signals at 2 KHz. Two high-density multipolar catheters were simulated (Advisor™ HD Grid and PentaRay®) and placed in a 2D region in which the simulated spiral wave persists longer. The configuration of the catheters was then modified by changing the number of electrodes, inter-electrodes distance, position, and atrial-wall distance for assessing how they would affect the rotor detection. In contact with the wall and at 1 mm distance from it, all the configurations detected the rotor correctly, irrespective of geometry, coverage, and inter-electrode distance. In the HDGrid-like geometry, the increase of the inter-electrode distance from 3 to 6 mm caused rotor detection failure at 2 mm distance from the LA wall. In the PentaRay-like configuration, regardless of inter-electrode distance, rotor detection failed at 3 mm endocardium-catheter distance. The asymmetry of this catheter resulted in rotation-dependent rotor detection. To conclude, the computational framework we developed is based on realistic catheter shapes designed with parameter configurations which resemble clinical settings. Results showed it is well suited to investigate how mapping catheter geometry and location affect AF driver detection, therefore it is a reliable tool to design and test new mapping catheters.

Published
2021

33. Indocyanine green fluorescence angiography after full‐thickness bowel resection for rectosigmoid endometriosis: A multicentric experience with quantitative analysis

Author

Raimondo, Diego, primary, Maletta, Manuela, additional, Malzoni, Mario, additional, Cosentino, Francesco, additional, Scambia, Giovanni, additional, Falcone, Francesca, additional, Coppola, Marina, additional, Turco, Luigi C., additional, Borghese, Giulia, additional, Raffone, Antonio, additional, Casadio, Paolo, additional, Fabbri, Claudio, additional, Corsi, Cristiana, additional, and Seracchioli, Renato, additional

Published
2021
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43. Development of a patient-specific model for stroke risk assessment in atrial fibrillation patients

Author

Corsi, Cristiana, Masci, Alessandro <1992>, Corsi, Cristiana, and Masci, Alessandro <1992>

Abstract

Atrial fibrillation is associated with a five-fold increase in the risk of cerebrovascular events,being responsible of 15-18% of all strokes.The morphological and functional remodelling of the left atrium caused by atrial fibrillation favours blood stasis and, consequently, stroke risk. In this context, several clinical studies suggest that stroke risk stratification could be improved by using haemodynamic information on the left atrium (LA) and the left atrial appendage (LAA). The goal of this study was to develop a personalized computational fluid-dynamics (CFD) model of the left atrium which could clarify the haemodynamic implications of atrial fibrillation on a patient specific basis. The developed CFD model was first applied to better understand the role of LAA in stroke risk. Infact, the interplay of the LAA geometric parameters such as LAA length, tortuosity, surface area and volume with the fluid-dynamics parameters and the effects of the LAA closure have not been investigated. Results demonstrated the capabilities of the CFD model to reproduce the real physiological behaviour of the blood flow dynamics inside the LA and the LAA. Finally, we determined that the fluid-dynamics parameters enhanced in this research project could be used as new quantitative indexes to describe the different types of AF and open new scenarios for the patient-specific stroke risk stratification.

Published
2021

48. Lipid sub-fractionation predicts worsening myocardial perfusion reserve in patients with low-density lipoprotein less than 100mg/dL: a regadenoson dardiac magnetic resonance study

Author

Narang Akhil, Yodwut Chattanong, Tarroni Giacomo, Estep Emily, Turner Kristen M, Freed Benjamin H, Bhave Nicole M, Corsi Cristiana, Davidson Michael H, Lang Roberto, Mor-Avi Victor, and Patel Amit R

Subjects
Diseases of the circulatory (Cardiovascular) system, RC666-701
Published
2012
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50. Supervised Learning Modelization and Segmentation of Cardiac Scar in Delayed Enhanced MRI

Author

Lara, Laura, primary, Vera, Sergio, additional, Perez, Frederic, additional, Lanconelli, Nico, additional, Morisi, Rita, additional, Donini, Bruno, additional, Turco, Dario, additional, Corsi, Cristiana, additional, Lamberti, Claudio, additional, Gavidia, Giovana, additional, Bordone, Maurizio, additional, Soudah, Eduardo, additional, Curzen, Nick, additional, Rosengarten, James, additional, Morgan, John, additional, Herrero, Javier, additional, and González Ballester, Miguel A., additional

Published
2013
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