Transesophageal high-intensity focused ultrasound (HIFU) energy can be used to treat cardiac arrhythmia efficiently non-invasively. Since the esophagus is located just behind the heart, it offers a perfect acoustic window. Hence, HIFU can be directed toward the heart to perform ablation. In a previous study a HIFU probe with one 2D US image perpendicular to the esophagus axis for guidance purpose has been proposed [1]. A new dualmode HIFU probe with two perpendicular 2D US imagining plane is now under development. In this paper we propose a therapy guidance system, based on an intensity-based registration of the two perpendicular 2D US to preoperative 3D CT. As a proof of concept we developed the following evaluation framework on a numerical phantom: 1) because the probe is under development we define a ground truth (GT) initial pose inside a CT volume and simulated two perpendicular US images from the CT data; 2) we run the registration framework from 55 randomly defined pose initialization around the initial GT pose; and 3) we estimated the accuracy of the registration by (a) the transformation parameter estimation errors (translation error and quaternion distance for rotation) and (b) Target Registration Error (TRE) on 8 features. The accuracy of the registration using two 2D US plane has been compared to previous work with only one US plane. An improvement was observed when using two 2D US planes with regards to the previous one US plane.
经食管高强度聚焦超声(HIFU)能量可用于无创治疗心律失常。由于食道位于心脏后面，它提供了一个完美的声学窗口。因此，HIFU可以直接对心脏进行消融。在先前的一项研究中，提出了一种HIFU探针，其二维超声图像垂直于食管轴以用于引导。一种新的双模HIFU探头，具有两个垂直的二维US成像平面，目前正在开发中。在本文中，我们提出了一种治疗指导系统，该系统基于两个垂直的2D US到术前3D CT的基于强度的配准。作为概念验证，我们在数值幻影上开发了以下评估框架:1)由于探针正在开发中，我们在CT体积内定义了一个ground truth (GT)初始姿态，并从CT数据中模拟了两个垂直的US图像;2)我们围绕初始GT姿态从55个随机定义的姿态初始化运行配准框架;3)通过(a)变换参数估计误差(平移误差和旋转四元数距离)和(b)目标配准误差(TRE)对8个特征进行配准精度估计。使用两个2D美制平面的配准精度与之前使用一个美制平面的配准精度进行了比较。当使用两架2D美国飞机时，与之前的一架美国飞机相比，我们观察到一个改进。
{"title":"High Intensity Focused Ultrasound Therapy Guidance System by Image-based Registration for Patients with Cardiac Fibrillation","authors":"Batoul Dahman, J. Dillenseger","doi":"10.22489/cinc.2019.315","DOIUrl":"https://doi.org/10.22489/cinc.2019.315","url":null,"abstract":"Transesophageal high-intensity focused ultrasound (HIFU) energy can be used to treat cardiac arrhythmia efficiently non-invasively. Since the esophagus is located just behind the heart, it offers a perfect acoustic window. Hence, HIFU can be directed toward the heart to perform ablation. In a previous study a HIFU probe with one 2D US image perpendicular to the esophagus axis for guidance purpose has been proposed [1]. A new dualmode HIFU probe with two perpendicular 2D US imagining plane is now under development. In this paper we propose a therapy guidance system, based on an intensity-based registration of the two perpendicular 2D US to preoperative 3D CT. As a proof of concept we developed the following evaluation framework on a numerical phantom: 1) because the probe is under development we define a ground truth (GT) initial pose inside a CT volume and simulated two perpendicular US images from the CT data; 2) we run the registration framework from 55 randomly defined pose initialization around the initial GT pose; and 3) we estimated the accuracy of the registration by (a) the transformation parameter estimation errors (translation error and quaternion distance for rotation) and (b) Target Registration Error (TRE) on 8 features. The accuracy of the registration using two 2D US plane has been compared to previous work with only one US plane. An improvement was observed when using two 2D US planes with regards to the previous one US plane.","PeriodicalId":6716,"journal":{"name":"2019 Computing in Cardiology Conference (CinC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80159755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A Low Dimensional Algorithm for Detection of Sepsis from Electronic Medical Record Data","authors":"Deogire Aruna","doi":"10.22489/cinc.2019.037","DOIUrl":"https://doi.org/10.22489/cinc.2019.037","url":null,"abstract":"","PeriodicalId":6716,"journal":{"name":"2019 Computing in Cardiology Conference (CinC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77127594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kontaxis Spyridon, Bailon Raquel, Rapalis Andrius, Brazaitis Marius, Cernych Margarita, Lázaro Plaza Jesús, Laguna Pablo, Gil Eduardo, Marozas Vaidotas
In this study, a heart rate variability (HRV) analysis guided by respiration is conducted to assess changes in autonomic nervous system (ANS) regulation during pronounced heat stress induced by repetitive exposures to dry sauna in 13 young healthy subjects. The spectral power at the low frequency (LF) band [0 . 04 , 0 . 15] Hz and at the high frequency band centered around the mean respiratory rate, estimated from ECG-derived respiration signals, are studied. The mean heart rate (HR), the total power of HRV, and the normalized LF power are also analyzed. Results show that mean HR and normalized LF power increase significantly after basal stage, not only during the sauna sessions, but also at the intermediate short rest stages and recovery phase after 30 min. A significant reduction in the total power of HRV during all sauna sessions is observed, while an increased power in LF band is shown only during recovery which might be related to improved cardiac function (increased cardiac output and reduced peripheral vascular resistance) after heat exposure. Respiratory rate does not change significantly during the protocol but a negative trend at stress stages may indicate a reverse reaction against an over-activation of the sympathetic branch. In conclusion, exposure to heat stress shifts sympathovagal balance of ANS toward sympathetic dominance that increases HR and diminishes
{"title":"Autonomic Nervous System Response to Heat Stress Exposure by Means of Heart Rate Variability","authors":"Kontaxis Spyridon, Bailon Raquel, Rapalis Andrius, Brazaitis Marius, Cernych Margarita, Lázaro Plaza Jesús, Laguna Pablo, Gil Eduardo, Marozas Vaidotas","doi":"10.22489/cinc.2019.197","DOIUrl":"https://doi.org/10.22489/cinc.2019.197","url":null,"abstract":"In this study, a heart rate variability (HRV) analysis guided by respiration is conducted to assess changes in autonomic nervous system (ANS) regulation during pronounced heat stress induced by repetitive exposures to dry sauna in 13 young healthy subjects. The spectral power at the low frequency (LF) band [0 . 04 , 0 . 15] Hz and at the high frequency band centered around the mean respiratory rate, estimated from ECG-derived respiration signals, are studied. The mean heart rate (HR), the total power of HRV, and the normalized LF power are also analyzed. Results show that mean HR and normalized LF power increase significantly after basal stage, not only during the sauna sessions, but also at the intermediate short rest stages and recovery phase after 30 min. A significant reduction in the total power of HRV during all sauna sessions is observed, while an increased power in LF band is shown only during recovery which might be related to improved cardiac function (increased cardiac output and reduced peripheral vascular resistance) after heat exposure. Respiratory rate does not change significantly during the protocol but a negative trend at stress stages may indicate a reverse reaction against an over-activation of the sympathetic branch. In conclusion, exposure to heat stress shifts sympathovagal balance of ANS toward sympathetic dominance that increases HR and diminishes","PeriodicalId":6716,"journal":{"name":"2019 Computing in Cardiology Conference (CinC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73601198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Elliott, O. Dössel, A. Loewe, L. Mainardi, V. Corino, Jose F Rodriguez Matas"
Improved understanding of the effects of variability in electrophysiological activity within the human heart is key to understanding and predicting cardiovascular response to disease and treatments. Previous studies have considered either regional variation in action potentials or inter-subject variability within a single region of the atria. In this study, we hypothesize that the regional differences in morphology derive not only from variation in dependence on individual conductances, but also from the relationship between multiple conductances. Using the Monte-Carlo Sampling Method and the Maleckar cellular model for electrophysiology, we created an in-silico population of models. Each conductance was varied +/100% from the standard model. The population was divided into regional groups based on biomarkers. Results showed regional variation in the dependence on relationships between conductances. In the right atrial appendage the value of gK1 was found to be only twice as influential as the relationship between gK1 and gKur on the APD90 biomarker. Other relationships that had a significant impact included gTo-gKur; gKr-gK1; gNaKgNaCa and gKur-gNaK for various regions. R values for first order linear regression models showed significant relationships were left out in the analysis. This was significantly improved in the second order R values.
{"title":"An In-Silico Study of the Effects of Conductance Variation on the Regionally Based Action Potential Morphology.","authors":"J. Elliott, O. Dössel, A. Loewe, L. Mainardi, V. Corino, Jose F Rodriguez Matas\"","doi":"10.22489/cinc.2019.314","DOIUrl":"https://doi.org/10.22489/cinc.2019.314","url":null,"abstract":"Improved understanding of the effects of variability in electrophysiological activity within the human heart is key to understanding and predicting cardiovascular response to disease and treatments. Previous studies have considered either regional variation in action potentials or inter-subject variability within a single region of the atria. In this study, we hypothesize that the regional differences in morphology derive not only from variation in dependence on individual conductances, but also from the relationship between multiple conductances. Using the Monte-Carlo Sampling Method and the Maleckar cellular model for electrophysiology, we created an in-silico population of models. Each conductance was varied +/100% from the standard model. The population was divided into regional groups based on biomarkers. Results showed regional variation in the dependence on relationships between conductances. In the right atrial appendage the value of gK1 was found to be only twice as influential as the relationship between gK1 and gKur on the APD90 biomarker. Other relationships that had a significant impact included gTo-gKur; gKr-gK1; gNaKgNaCa and gKur-gNaK for various regions. R values for first order linear regression models showed significant relationships were left out in the analysis. This was significantly improved in the second order R values.","PeriodicalId":6716,"journal":{"name":"2019 Computing in Cardiology Conference (CinC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83319360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Purkinje network (PN) gains more clinically importance as it becomes target for pacing in rate control and defibrillation. However, our understanding of the PN morphology arises from animal experiments, which might not transfer to humans. Therefore, we propose an automated computer simulation predicting physiological PN morphologies depending on the heart shape. It starts by generating virtual heart shapes from a statistical shape atlas and generates virtual PNs on the endocardial surface. For the combined virtual models the eikonal equation is solved to estimate the local activation times throughout the myocardium, which then feed forward to an simulation of the 12-lead surface ECG. From the simulated ECG the QRS-complex is compared against a healthy standard QRS-complex ,which allows to estimate how physiological a PN morphology is. In our model, only bundle branch bifurcation points near the base or near the apex result in physiological QRS wave forms. For the right bundle, more physiological QRS waves can be obtained when the branching point is at the apex. Only a minor dependency of the ECG on the heart shape is found. However, a strong correlation between the bundle branch bifurcation points themselves is observed.
{"title":"Predicting Plausible Human Purkinje Network Morphology from Simulations","authors":"M. Lange, T. Lassila, Alejandro F Frangi","doi":"10.22489/cinc.2019.168","DOIUrl":"https://doi.org/10.22489/cinc.2019.168","url":null,"abstract":"The Purkinje network (PN) gains more clinically importance as it becomes target for pacing in rate control and defibrillation. However, our understanding of the PN morphology arises from animal experiments, which might not transfer to humans. Therefore, we propose an automated computer simulation predicting physiological PN morphologies depending on the heart shape. It starts by generating virtual heart shapes from a statistical shape atlas and generates virtual PNs on the endocardial surface. For the combined virtual models the eikonal equation is solved to estimate the local activation times throughout the myocardium, which then feed forward to an simulation of the 12-lead surface ECG. From the simulated ECG the QRS-complex is compared against a healthy standard QRS-complex ,which allows to estimate how physiological a PN morphology is. In our model, only bundle branch bifurcation points near the base or near the apex result in physiological QRS wave forms. For the right bundle, more physiological QRS waves can be obtained when the branching point is at the apex. Only a minor dependency of the ECG on the heart shape is found. However, a strong correlation between the bundle branch bifurcation points themselves is observed.","PeriodicalId":6716,"journal":{"name":"2019 Computing in Cardiology Conference (CinC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81317853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The method of fundamental solutions (MFS) has been extensively used for the electrocardiographic imaging (ECGI) inverse problem. One of its advantages is that it is a meshless method. We remarked that the using cm instead of mm as a space unit has a high impact on the reconstructed inverse solution. Our purpose is to refine this observation, by introducing a rescaling coefficient in space and study its effect on the MFS inverse solution. Results are provided using simulated test data prepared using a reaction-diffusion model. We then computed the ECGI inverse solution for rescaling coefficient values varying from 1 to 100, and computed the relative error (RE) and correlation coefficient (CC). This approach improved the RE and CC by at least 10% but can go up to 40% independently of the pacing site. We concluded that the optimal coefficient depends on the heterogeneity and anisotropy of the torso and does not depend on the stimulation site. This suggests that it is related to an optimal equivalent conductivity estimation in the torso domain.
{"title":"Space Rescaling in the MFS Method Improves the ECGI Reconstruction","authors":"N. Zemzemi, Pauline Migerditichan, M. Potse","doi":"10.22489/cinc.2019.333","DOIUrl":"https://doi.org/10.22489/cinc.2019.333","url":null,"abstract":"The method of fundamental solutions (MFS) has been extensively used for the electrocardiographic imaging (ECGI) inverse problem. One of its advantages is that it is a meshless method. We remarked that the using cm instead of mm as a space unit has a high impact on the reconstructed inverse solution. Our purpose is to refine this observation, by introducing a rescaling coefficient in space and study its effect on the MFS inverse solution. Results are provided using simulated test data prepared using a reaction-diffusion model. We then computed the ECGI inverse solution for rescaling coefficient values varying from 1 to 100, and computed the relative error (RE) and correlation coefficient (CC). This approach improved the RE and CC by at least 10% but can go up to 40% independently of the pacing site. We concluded that the optimal coefficient depends on the heterogeneity and anisotropy of the torso and does not depend on the stimulation site. This suggests that it is related to an optimal equivalent conductivity estimation in the torso domain.","PeriodicalId":6716,"journal":{"name":"2019 Computing in Cardiology Conference (CinC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78239034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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