Identification of border-zone corridors in the left ventricle using the core expansion method

2017 ◽  
Author(s):  
L. Serra ◽  
R. M. Figueras i Ventura ◽  
X. Planes ◽  
M. Steghöfer ◽  
J. Fernández-Armenta ◽  
...  
Keyword(s):  
Left Ventricle ◽  
Expansion Method ◽  
Border Zone ◽  
The Core

P1129Bipolar voltage cut-off validation in electroanatomical voltage mapping to identify scar and conduction channels in ventricular tachycardia ablation: need for new cut-off in NICM

EP Europace ◽  
2020 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
F Zaraket ◽  
P Sanchez Somonte ◽  
L Quinto ◽  
P Garre ◽  
F Alarcon ◽  
...  
Keyword(s):  
Ventricular Tachycardia ◽  
Current Practice ◽  
Daily Practice ◽  
Border Zone ◽  
Ventricular Tachycardia Ablation ◽  
The Core ◽  
Bipolar Voltage ◽  
Voltage Mapping ◽  
Baseline Characteristics ◽  
Vt Ablation

Abstract Background/Introduction Substrate-guided techniques have changed the approach and results of ventricular tachycardia (VT) ablation and electroanatomical voltage mapping (EAVM) constitutes a diagnostic and therapeutic cornerstone in this field. In current practice normal myocardium is typically characterized by bipolar voltage > 1.5 mV, dense scar < 0.5 mV, and border zone (BZ) tissue by the range between 0.5 to 1.5 mV. Of note, evidence for these cut-off values has been derived in humans from small observational studies and in animals. Furthermore, some studies suggest that only the 60% of not transmural endocardial scars and the 35% of not endocardial scars are detected without any adjustment of these values. New voltage cut-off values are needed. Purpose The purpose of this study is to adjust voltage cut off in order to establish the threshold that more accurately define the pathological substrate in VT ablation. Additionally, predictors of usefulness of current thresholds are analyzed. Methods EAVM were created with CARTO3 System and Sensor-Force catheter (Navistar Smart-Touch and Pentaray). We delineated the conducting channels by analyzing the late potentials activation. Based on these channels we looked for the best cut-off values to detect these channels. We describe the baseline characteristics, the best cut-off values for border zone and scar core in our series and we analyzed the accuracy of the current established values to detect the arrhythmogenic VT substrate Results We investigated 51 patients (74,5% males; 41,2% ischemic cardiomyopathy, mean LVEF 38,6% +/-13,6) with sustained monomorphic VT submitted to ablation during 2016 and 2017. The range of the voltage adjustment was from 0,01-1 mV for core area and 0,2-6mV as maximum, with an average of 0,31-1,42mV. Using currently accepted bipolar voltage cut-off <0.5 mV the core scar was correctly identified in 80,4% of patients: 90,4% in ischemic and 73,3% in NICM. Regarding BZ, using classical cut off (0.5-1.5mV) only 56,9 % of the cases were well identified: interestingly, accuracy was worse in NICM (46,6%) than in ischemic patients (71,4%) (p = 0,07). Conclusions EAVM is very important to detect scar and channels in VT ablation, but several elements can affect it and recently the traditional voltage values have been questioned. Our study suggests how the threshold as currently applied in daily practice could be acceptable to detect the core scar area, but it has to be reconsidered in NICM, especially regarding the border zone. An evident trend (p = 0,07) suggests a better accuracy of current values to define VT substrate in ischemic patients than in NICM. Abstract Figure. Channel Identification

Nodal Expansion and its Application in AP1000 Nuclear Reactor Core Monitoring System

2013 ◽  
Vol 448-453 ◽  
pp. 1907-1911
Author(s):  
Wei Zhi Jia ◽  
Rui Wang ◽  
Yun Zhou
Keyword(s):  
Monitoring System ◽  
Nuclear Reactor ◽  
Reactor Core ◽  
Expansion Method ◽  
The Core ◽  
Nodal Model ◽  
Nuclear Reactor Core ◽  
Nodal Expansion Method ◽  
Full Core

As the core monitoring system of AP1000, BEACON always uses a full-core nodal model for core monitoring based on the ANC-NEM nodal model. The theory behind the nodal expansion method is discussed, and the application of the method in BEACON is described. Finally, an ANC-NEM calculation simulation is proposed.

scholarly journals Polarization tensor vanishing structure of general shape: Existence for small perturbations of balls

2020 ◽  
pp. 1-32
Author(s):  
Hyeonbae Kang ◽  
Xiaofei Li ◽  
Shigeru Sakaguchi
Keyword(s):  
Small Volume ◽  
Expansion Method ◽  
Two Dimensions ◽  
Degree Zero ◽  
Polarization Tensor ◽  
General Shape ◽  
Small Perturbations ◽  
Geometric Quantity ◽  
The Core ◽  
Boundary Measurements

The polarization tensor is a geometric quantity associated with a domain. It is a signature of the small inclusion’s existence inside a domain and used in the small volume expansion method to reconstruct small inclusions by boundary measurements. In this paper, we consider the question of the polarization tensor vanishing structure of general shape. The only known examples of the polarization tensor vanishing structure are concentric disks and balls. We prove, by the implicit function theorem on Banach spaces, that a small perturbation of a ball can be enclosed by a domain so that the resulting inclusion of the core-shell structure becomes polarization tensor vanishing. The boundary of the enclosing domain is given by a sphere perturbed by spherical harmonics of degree zero and two. This is a continuation of the earlier work (Kang, Li, Sakaguchi) for two dimensions.

To Improve the Accuaracy of Harmonic Synthesis Method by Using More Detectors in Azimuthal Direction in HTR

2014 ◽  
Author(s):  
Kai Fan ◽  
Fu Li ◽  
Xuhua Zhou
Keyword(s):  
Power Distribution ◽  
Synthesis Method ◽  
Expansion Method ◽  
Azimuthal Direction ◽  
Neutron Detectors ◽  
Tsinghua University ◽  
The Core ◽  
Demonstration Plant ◽  
Polynomial Expansion Method ◽  
High Temperature Gas

Modular high temperature gas cooled reactor HTR-PM demonstration plant, designed by INET, Tsinghua University, is being built in Shidaowan, Shandong province, China. HTR-PM adopts pebble bed concept. Like other HTR, monitoring the core power distribution of HTR-PM is very important but challenging, as there is no in-core neutron detectors. There are some proposals to reconstruct the power distribution using the readings of ex-core neutron detectors. One method is harmonic synthesis method. In HTR, the neutron detectors are arranging symmetrically; and the power distribution of the core is also symmetrical. So in the before, only one set of detectors were used to reconstruct the power distribution, for considering the readings of different sets were almost same. In this paper, all readings of the neutron detectors were used, and new results were calculated and evaluated. It is showed that using more detector readings has no help to the accuracy of the harmonic synthesis method but improve the robustness of the method obvious. Using more detectors could improve both the robustness and the accuracy to the harmonics’ coefficients polynomial expansion method.

scholarly journals Regional wall mechanics in the ischemic left ventricle: numerical modeling and dog experiments

1996 ◽  
Vol 270 (1) ◽  
pp. H398-H410 ◽  
Author(s):  
P. H. Bovendeerd ◽  
T. Arts ◽  
T. Delhaas ◽  
J. M. Huyghe ◽  
D. H. van Campen ◽  
...  
Keyword(s):  
Left Ventricle ◽  
Mechanical Performance ◽  
Border Zone ◽  
Myocardial Tissue ◽  
Deformation Pattern ◽  
Stroke Work ◽  
Fiber Stress ◽  
Model Simulations ◽  
Ischemic Region ◽  
Strain And Strain Rate

The mechanics of the ischemic left ventricle during a complete cardiac cycle were simulated using a finite-element model accounting for the thick-walled ventricular geometry, the fibrous nature of the myocardial tissue, and the dependency of active muscle fiber stress on time, strain, and strain rate. Ischemia was modeled by disabling the generation of active stress in a region comprising approximately 12% of total wall volume. In the model simulations, the approximately 12% reduction in the amount of normally contracting tissue resulted in an approximately 25% reduction in stroke work compared with the normal situation. The more-than-proportional loss of stroke work may partly be attributed to storage of elastic energy in the bulging ischemic region. Furthermore the mechanical performance in the nonischemic border zone deteriorated because of reduced systolic fiber stress (if fibers were in series with those in the ischemic region) or reduced fiber shortening (if fibers were parallel). The deformation pattern of the ventricle was asymmetric with respect to the ischemic region because of the anisotropy of the myocardial tissue. Epicardial fiber shortening in and around the ischemic region, as predicted from the model simulations, was in qualitative agreement with shortening, as measured in four dogs in which ischemia was induced by occlusion of the distal part of the left anterior interventricular coronary artery.

scholarly journals The Direct Incorporation of Perfusion Defect Information to Define Ischemia and Infarction in a Finite Element Model of the Left Ventricle

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Alexander I. Veress ◽  
George S. K. Fung ◽  
Taek-Soo Lee ◽  
Benjamin M. W. Tsui ◽  
Gregory A. Kicska ◽  
...  
Keyword(s):  
Finite Element ◽  
Left Ventricle ◽  
Image Data ◽  
Element Model ◽  
Border Zone ◽  
Average Intensity ◽  
Cardiac Image ◽  
Mechanical Models ◽  
Highly Correlated ◽  
Perfusion Maps

This paper describes the process in which complex lesion geometries (specified by computer generated perfusion defects) are incorporated in the description of nonlinear finite element (FE) mechanical models used for specifying the motion of the left ventricle (LV) in the 4D extended cardiac torso (XCAT) phantom to simulate gated cardiac image data. An image interrogation process was developed to define the elements in the LV mesh as ischemic or infarcted based upon the values of sampled intensity levels of the perfusion maps. The intensity values were determined for each of the interior integration points of every element of the FE mesh. The average element intensity levels were then determined. The elements with average intensity values below a user-controlled threshold were defined as ischemic or infarcted depending upon the model being defined. For the infarction model cases, the thresholding and interrogation process were repeated in order to define a border zone (BZ) surrounding the infarction. This methodology was evaluated using perfusion maps created by the perfusion cardiac-torso (PCAT) phantom an extension of the 4D XCAT phantom. The PCAT was used to create 3D perfusion maps representing 90% occlusions at four locations (left anterior descending (LAD) segments 6 and 9, left circumflex (LCX) segment 11, right coronary artery (RCA) segment 1) in the coronary tree. The volumes and shapes of the defects defined in the FE mechanical models were compared with perfusion maps produced by the PCAT. The models were incorporated into the XCAT phantom. The ischemia models had reduced stroke volume (SV) by 18–59 ml. and ejection fraction (EF) values by 14–50% points compared to the normal models. The infarction models, had less reductions in SV and EF, 17–54 ml. and 14–45% points, respectively. The volumes of the ischemic/infarcted regions of the models were nearly identical to those volumes obtained from the perfusion images and were highly correlated (R2 = 0.99).

scholarly journals From Body Mantle To Internal Core - A Parallel Framework To Organ Systems

2020 ◽  
pp. 1-12
Author(s):  
Yu Edwin Chau-Leung ◽  
Keyword(s):  
Operating Systems ◽  
The Body ◽  
Border Zone ◽  
Whole Body ◽  
The Core ◽  
System A ◽  
Self Organized ◽  
Surrounding Environment ◽  
Organ Systems ◽  
Internal Core

A framework describing a body perspective that can be used under Western Medicine (WM) and Chinese Medicine (CM) in parallel would facilitate a concerted look at the body in both perspectives. The major body systems may be viewed as operating systems, while closely interactive organ clusters forming whole body subsystems sub serve life functions. The whole body is viewed in layers: with the Mantle as border zone, the under-layer Interface as interactional zone, the Core with organ systems, and the Deep biostratum of resources. The mantle acts as a barrier and interface, while the under-layer of fascial, circulatory and neurohumoral elements inter-relate with deeper provisions, supporting and stabilizing activities. The operating systems and life vigor subsystems function up to a surface border-zone to interact effectively and adaptively with the surrounding environment. While current academics consider the dynamic brain tightly integrated with the body as a self-organized system, a clinical framework is lacking. This paper provides a more or less seamless framework between social, physical, biochemical and cellular perspectives, which have formerly been dichotomizing with big gaps. With such a framework, WM workers can expand onto using some parts of the CM perspectives, not losing scientific emphasis of cellular studies, while recognizing that whole body processes in many clinical occasions can explain problems and be handled more effectively. This has implications in diagnosis and understanding pathophysiology. Accordingly, a spectrum of practice modes in medicine presented helps to understand clinical approaches, from lesion to complexity treatment.

Transmural variation in the relationship between myocardial infarct size and risk area

1982 ◽  
Vol 242 (5) ◽  
pp. H867-H874 ◽  
Author(s):  
S. Koyanagi ◽  
C. L. Eastham ◽  
D. G. Harrison ◽  
M. L. Marcus
Keyword(s):  
Left Ventricle ◽  
Regional Blood Flow ◽  
Myocardial Infarct ◽  
Border Zone ◽  
Pathological Examination ◽  
Myocardial Infarct Size ◽  
Collateral Flow ◽  
Flow Measurements ◽  
Infarct Area ◽  
The Relationship

To test the hypothesis that the relationship between infarct area (IA) and area at risk (AR) varies in different layers of the left ventricle (LV), we occluded the circumflex coronary artery for 48 h in 20 conscious dogs. AR was determined by postmortem coronary stereoarteriography, and infarct area by pathological examination. Both AR and IA were divided into four layers: posterior papillary muscle (PPM), subendocardium (Endo), midwall, and subepicardium (Epi) and quantified with planimetry. Hemodynamics and regional myocardial flow with tracer microspheres (7-10 micrometers diam) were measured before and after coronary occlusion. IA was closely correlated with AR for PPM (r = 0.96), Endo (r = 0.97), and Epi (r = 0.92). However, the slope of IA/AR for Endo (1.30 +/- 0.08) was significantly steeper (P less than 0.05) than that for Epi (0.89 +/- 0.11); furthermore, the intercepts at zero infarction for PPM (0.5 +/- 0.1% of LV), Endo (4.2 +/- 0.4%), and Epi (0.1 +/- 0.7%) were significantly different from each other. Regional blood flow measurements indicate that the differences in IA/AR in various layers reflected earlier and greater total collateral flow to the noninfarcted AR in the epicardium. Thus IA/AR for the entire LV is a composite representing separate IA/AR specific to various transmural layers of the LV. In addition, this study demonstrates that the lateral border zone between the IA and the AR is minimal (less than 3-5 mm) in the subendocardium and midwall layers of the left ventricle.

scholarly journals P784Identification of border-zone corridors in the left ventricle with late-enhancement magnetic resonance images

EP Europace ◽  
2018 ◽  
Vol 20 (suppl_1) ◽  
pp. i138-i138
Author(s):  
M Steghoefer ◽  
R M Figueras I Ventura ◽  
D Soto-Iglesias ◽  
X Planes ◽  
A Berruezo ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Left Ventricle ◽  
Late Enhancement ◽  
Magnetic Resonance Images ◽  
Border Zone

Profit Expansion Method by Standard as an Outbound Open Innovation

2019 ◽  
pp. 256-275
Author(s):  
Manabu Eto
Keyword(s):  
Technology Management ◽  
Control Strategy ◽  
Open Innovation ◽  
Management Strategies ◽  
Expansion Method ◽  
Target Product ◽  
The Core ◽  
Standard Essential Patents ◽  
Technology Control

Among open innovations, standardization activities that do not cause some souse of profits, such as issuing standard essential patents for standardized technologies, can be said to be offering-type outbound open innovations. Technology providers require a careful strategy to make a profit from standardization activities. The core of this is to determine in what state the technology in the target product itself will be kept, which is the technology control strategy. What is particularly important is to determine what information will be proactively disclosed based on the theory, utility, and implementation of the technology, and what information will be kept secret. In this chapter, the author examines several cases of standardization and, by focusing on those that earned profits, presents technology management strategies that generate profits using standardization.

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