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Muhammad Ashraf - One of the best experts on this subject based on the ideXlab platform.
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Mitigation of Variability among 3D Echocardiography-Derived Regional Strain Values Acquired by Multiple Ultrasound Systems by Vendor Independent Analysis.
PloS one, 2016Co-Authors: Cole Streiff, Meihua Zhu, David J. Sahn, Eriko Shimada, Muhammad AshrafAbstract:Introduction This study compared the variability of 3D echo derived circumferential and longitudinal Strain values computed from vendor-specific and vendor-independent analyses of images acquired using ultrasound systems from different vendors. Methods Ten freshly harvested porcine hearts were studied. Each heart was mounted on a custom designed phantom and driven to simulate normal cardiac motion. Cardiac rotation was digitally controlled and held constant at 5°, while pumped stroke volume (SV) ranged from 30-70ml. Full-volume image data was acquired using three different ultrasound systems from different vendors. The image data was analyzed for longitudinal and circumferential Strains (LS, CS) using both vendor-specific and vendor-independent analysis packages. Results Good linear relationships were observed for each vendor-specific analysis package for both CS and LS at the mid-anterior segment, with correlation coefficients ranging from 0.82–0.91 (CS) and 0.86–0.89 (LS). Comparable linear regressions were observed for results determined by a vendor independent program (CS: R = 0.82–0.89; LS: R = 0.86–0.89). Variability between analysis packages was examined via a series of ANOVA tests. A statistical difference was found between vendor-specific analysis packages (p 0.05). Conclusions Circumferential and longitudinal Regional Strain values differ when quantified by vendor-specific analysis packages; however, this variability is mitigated by use of a vendor-independent quantification method. These results suggest that echocardiograms acquired using different ultrasound systems could be meaningfully compared using vendor-independent software.
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Cardiac Regional Strain Evaluation for Hypertrophic Cardiomyopathy Using 4d Echocardiography
Journal of the American College of Cardiology, 2016Co-Authors: David J. Sahn, Muhammad Ashraf, Hannah Tam, Lydia Tam, Meihua ZhuAbstract:Strain analysis is essential for evaluating the progress of hypertrophic cardiomyopathy (HCM). Four-dimensional speckle-tracking echocardiography (4D-STE) has shown to be a superior method in Strain evaluation when compared to tissue Doppler imaging (TDI) and two-dimensional speckle-tracking
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Regional Strain determination and myocardial infarction detection by three-dimensional echocardiography with varied temporal resolution.
Echocardiography (Mount Kisco N.Y.), 2014Co-Authors: Meihua Zhu, Jill Panosian, David J. Sahn, B A Cole Streiff, Zhijun Zhang, Xubo Song, Muhammad AshrafAbstract:Background: Three-dimensional echocardiography (3DE) is a promising method for Strain determination; however, there are temporal resolution concerns. This study aims to evaluate the feasibility and accuracy of 3DE on longitudinal and circumferential Strain (LS, CS) determination and infarction detection under variable frame rates (FR) and “heart rates” (stroke rates [SR]) conditions. Methods: Latex balloons were sewn into the left ventricle (LV) of 20 freshly harvested pig hearts which were then passively driven by a pulsatile pump apparatus at stroke volumes (SV) 30–70 mL. The hearts were pumped at 2 normal limits of human heart rate. Full-volume data were acquired before and after a simulated myocardial infarction (MI) at the 2 most commonly used FRs. LS and CS values were evaluated against sonomicrometry. Results: Longitudinal Strain and CS derived from high FR acquisitions showed statistically superior correlations with sonomicrometry data (LS: R 2 = 0.85, CS: R 2 = 0.84) than Strain values from low FR (LS: R 2 = 0.78, CS: R 2 = 0.76) (all P < 0.01). After MI induction, LS and CS at different FRs were significantly decreased while maintaining excellent correlations with sonomicrometry data (all P < 0.001). There is no statistical difference of Strain values between different SR acquisitions. Conclusion: Three-dimensional wall-motion tracking has the ability to accurately determine Regional myocardial deformation and detect MI. Different heart rates within a physiologically relevant range have no effect on 3D Strain accuracy. Strain values calculated from higher frame rate acquisitions were found to have a slightly better accuracy. (Echocardiography 2014;00:1–10)
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Abstract 10677: A Validation of Circumferential and Longitudinal Regional Strain in Pumped Hearts Modeling Normal Function Compared to Simulated Myocardial Infarction Generated From Three-Dimensional Echocardiographic Feature Tracking Compared to Son
Circulation, 2011Co-Authors: Cole Streiff, Jill Panosian, Meihua Zhu, Muhammad Ashraf, David J. SahnAbstract:Background: Three-dimensional (3D) echocardiography provides visualization of the complex anatomy of heart structures throughout the cardiac cycle. Quantitative global and Regional Strain values ma...
Meihua Zhu - One of the best experts on this subject based on the ideXlab platform.
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Mitigation of Variability among 3D Echocardiography-Derived Regional Strain Values Acquired by Multiple Ultrasound Systems by Vendor Independent Analysis.
PloS one, 2016Co-Authors: Cole Streiff, Meihua Zhu, David J. Sahn, Eriko Shimada, Muhammad AshrafAbstract:Introduction This study compared the variability of 3D echo derived circumferential and longitudinal Strain values computed from vendor-specific and vendor-independent analyses of images acquired using ultrasound systems from different vendors. Methods Ten freshly harvested porcine hearts were studied. Each heart was mounted on a custom designed phantom and driven to simulate normal cardiac motion. Cardiac rotation was digitally controlled and held constant at 5°, while pumped stroke volume (SV) ranged from 30-70ml. Full-volume image data was acquired using three different ultrasound systems from different vendors. The image data was analyzed for longitudinal and circumferential Strains (LS, CS) using both vendor-specific and vendor-independent analysis packages. Results Good linear relationships were observed for each vendor-specific analysis package for both CS and LS at the mid-anterior segment, with correlation coefficients ranging from 0.82–0.91 (CS) and 0.86–0.89 (LS). Comparable linear regressions were observed for results determined by a vendor independent program (CS: R = 0.82–0.89; LS: R = 0.86–0.89). Variability between analysis packages was examined via a series of ANOVA tests. A statistical difference was found between vendor-specific analysis packages (p 0.05). Conclusions Circumferential and longitudinal Regional Strain values differ when quantified by vendor-specific analysis packages; however, this variability is mitigated by use of a vendor-independent quantification method. These results suggest that echocardiograms acquired using different ultrasound systems could be meaningfully compared using vendor-independent software.
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Cardiac Regional Strain Evaluation for Hypertrophic Cardiomyopathy Using 4d Echocardiography
Journal of the American College of Cardiology, 2016Co-Authors: David J. Sahn, Muhammad Ashraf, Hannah Tam, Lydia Tam, Meihua ZhuAbstract:Strain analysis is essential for evaluating the progress of hypertrophic cardiomyopathy (HCM). Four-dimensional speckle-tracking echocardiography (4D-STE) has shown to be a superior method in Strain evaluation when compared to tissue Doppler imaging (TDI) and two-dimensional speckle-tracking
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Regional Strain determination and myocardial infarction detection by three-dimensional echocardiography with varied temporal resolution.
Echocardiography (Mount Kisco N.Y.), 2014Co-Authors: Meihua Zhu, Jill Panosian, David J. Sahn, B A Cole Streiff, Zhijun Zhang, Xubo Song, Muhammad AshrafAbstract:Background: Three-dimensional echocardiography (3DE) is a promising method for Strain determination; however, there are temporal resolution concerns. This study aims to evaluate the feasibility and accuracy of 3DE on longitudinal and circumferential Strain (LS, CS) determination and infarction detection under variable frame rates (FR) and “heart rates” (stroke rates [SR]) conditions. Methods: Latex balloons were sewn into the left ventricle (LV) of 20 freshly harvested pig hearts which were then passively driven by a pulsatile pump apparatus at stroke volumes (SV) 30–70 mL. The hearts were pumped at 2 normal limits of human heart rate. Full-volume data were acquired before and after a simulated myocardial infarction (MI) at the 2 most commonly used FRs. LS and CS values were evaluated against sonomicrometry. Results: Longitudinal Strain and CS derived from high FR acquisitions showed statistically superior correlations with sonomicrometry data (LS: R 2 = 0.85, CS: R 2 = 0.84) than Strain values from low FR (LS: R 2 = 0.78, CS: R 2 = 0.76) (all P < 0.01). After MI induction, LS and CS at different FRs were significantly decreased while maintaining excellent correlations with sonomicrometry data (all P < 0.001). There is no statistical difference of Strain values between different SR acquisitions. Conclusion: Three-dimensional wall-motion tracking has the ability to accurately determine Regional myocardial deformation and detect MI. Different heart rates within a physiologically relevant range have no effect on 3D Strain accuracy. Strain values calculated from higher frame rate acquisitions were found to have a slightly better accuracy. (Echocardiography 2014;00:1–10)
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Abstract 10677: A Validation of Circumferential and Longitudinal Regional Strain in Pumped Hearts Modeling Normal Function Compared to Simulated Myocardial Infarction Generated From Three-Dimensional Echocardiographic Feature Tracking Compared to Son
Circulation, 2011Co-Authors: Cole Streiff, Jill Panosian, Meihua Zhu, Muhammad Ashraf, David J. SahnAbstract:Background: Three-dimensional (3D) echocardiography provides visualization of the complex anatomy of heart structures throughout the cardiac cycle. Quantitative global and Regional Strain values ma...
David J. Sahn - One of the best experts on this subject based on the ideXlab platform.
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Mitigation of Variability among 3D Echocardiography-Derived Regional Strain Values Acquired by Multiple Ultrasound Systems by Vendor Independent Analysis.
PloS one, 2016Co-Authors: Cole Streiff, Meihua Zhu, David J. Sahn, Eriko Shimada, Muhammad AshrafAbstract:Introduction This study compared the variability of 3D echo derived circumferential and longitudinal Strain values computed from vendor-specific and vendor-independent analyses of images acquired using ultrasound systems from different vendors. Methods Ten freshly harvested porcine hearts were studied. Each heart was mounted on a custom designed phantom and driven to simulate normal cardiac motion. Cardiac rotation was digitally controlled and held constant at 5°, while pumped stroke volume (SV) ranged from 30-70ml. Full-volume image data was acquired using three different ultrasound systems from different vendors. The image data was analyzed for longitudinal and circumferential Strains (LS, CS) using both vendor-specific and vendor-independent analysis packages. Results Good linear relationships were observed for each vendor-specific analysis package for both CS and LS at the mid-anterior segment, with correlation coefficients ranging from 0.82–0.91 (CS) and 0.86–0.89 (LS). Comparable linear regressions were observed for results determined by a vendor independent program (CS: R = 0.82–0.89; LS: R = 0.86–0.89). Variability between analysis packages was examined via a series of ANOVA tests. A statistical difference was found between vendor-specific analysis packages (p 0.05). Conclusions Circumferential and longitudinal Regional Strain values differ when quantified by vendor-specific analysis packages; however, this variability is mitigated by use of a vendor-independent quantification method. These results suggest that echocardiograms acquired using different ultrasound systems could be meaningfully compared using vendor-independent software.
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Cardiac Regional Strain Evaluation for Hypertrophic Cardiomyopathy Using 4d Echocardiography
Journal of the American College of Cardiology, 2016Co-Authors: David J. Sahn, Muhammad Ashraf, Hannah Tam, Lydia Tam, Meihua ZhuAbstract:Strain analysis is essential for evaluating the progress of hypertrophic cardiomyopathy (HCM). Four-dimensional speckle-tracking echocardiography (4D-STE) has shown to be a superior method in Strain evaluation when compared to tissue Doppler imaging (TDI) and two-dimensional speckle-tracking
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Regional Strain determination and myocardial infarction detection by three-dimensional echocardiography with varied temporal resolution.
Echocardiography (Mount Kisco N.Y.), 2014Co-Authors: Meihua Zhu, Jill Panosian, David J. Sahn, B A Cole Streiff, Zhijun Zhang, Xubo Song, Muhammad AshrafAbstract:Background: Three-dimensional echocardiography (3DE) is a promising method for Strain determination; however, there are temporal resolution concerns. This study aims to evaluate the feasibility and accuracy of 3DE on longitudinal and circumferential Strain (LS, CS) determination and infarction detection under variable frame rates (FR) and “heart rates” (stroke rates [SR]) conditions. Methods: Latex balloons were sewn into the left ventricle (LV) of 20 freshly harvested pig hearts which were then passively driven by a pulsatile pump apparatus at stroke volumes (SV) 30–70 mL. The hearts were pumped at 2 normal limits of human heart rate. Full-volume data were acquired before and after a simulated myocardial infarction (MI) at the 2 most commonly used FRs. LS and CS values were evaluated against sonomicrometry. Results: Longitudinal Strain and CS derived from high FR acquisitions showed statistically superior correlations with sonomicrometry data (LS: R 2 = 0.85, CS: R 2 = 0.84) than Strain values from low FR (LS: R 2 = 0.78, CS: R 2 = 0.76) (all P < 0.01). After MI induction, LS and CS at different FRs were significantly decreased while maintaining excellent correlations with sonomicrometry data (all P < 0.001). There is no statistical difference of Strain values between different SR acquisitions. Conclusion: Three-dimensional wall-motion tracking has the ability to accurately determine Regional myocardial deformation and detect MI. Different heart rates within a physiologically relevant range have no effect on 3D Strain accuracy. Strain values calculated from higher frame rate acquisitions were found to have a slightly better accuracy. (Echocardiography 2014;00:1–10)
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Abstract 10677: A Validation of Circumferential and Longitudinal Regional Strain in Pumped Hearts Modeling Normal Function Compared to Simulated Myocardial Infarction Generated From Three-Dimensional Echocardiographic Feature Tracking Compared to Son
Circulation, 2011Co-Authors: Cole Streiff, Jill Panosian, Meihua Zhu, Muhammad Ashraf, David J. SahnAbstract:Background: Three-dimensional (3D) echocardiography provides visualization of the complex anatomy of heart structures throughout the cardiac cycle. Quantitative global and Regional Strain values ma...
Hae Chang Gea - One of the best experts on this subject based on the ideXlab platform.
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Application of Regional Strain energy in topology optimization with inertia relief analysis
Volume 3A: 39th Design Automation Conference, 2013Co-Authors: Wei Song, Hae Chang Gea, Ren-jye Yang, Ching-hung ChuangAbstract:In finite element analysis, inertia relief solves the response of an unconStrained structure subject to constant or slowly varying external loads with static analysis computational cost. It is very attractive to utilize it in topology optimization to design structures under unbalanced loads, such as in impact and drop phenomena. In this paper, Regional Strain energy formulation and inertia relief is integrated into topology optimization to design protective structure under unbalanced loads. For background, the equations of inertia relief are introduced and a commonly used solving method is revisited. Then the Regional Strain energy formulation for topology optimization with inertia relief is proposed and its sensitivity is derived from the adjoint method. Based on the solving method, the sensitivity is evaluated term by term to simplify the results. The simplified sensitivity can be calculated easily using the output of commercial finite element packages. Finally, the effectiveness of this formulation is shown in the first example and the proposed Regional Strain energy formulation for topology optimization with inertia relief are presented and discussed in the protective structure design examples.Copyright © 2013 by ASME
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Applications of Regional Strain energy in compliant structure design for energy absorption
Structural and Multidisciplinary Optimization, 2004Co-Authors: Hae Chang GeaAbstract:Topology optimization of Regional Strain energy is studied in this paper. Unlike the conventional mean compliance formulation, this paper considers two main functions of structure: rigidity and compliance. For normal usages, rigidity is chosen as the design objective. For compliant design, a portion of the structure absorbs energy, while another part maintains the structural integrity. Therefore, we implemented a Regional Strain energy formulation for topology optimization. Sensitivity to Regional Strain energy is derived from the adjoint method. Numerical results from the proposed formulation are presented.
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Design for Energy Absorption: A Topology Optimization Approach
Volume 2A: 27th Design Automation Conference, 2001Co-Authors: Hae Chang Gea, Jianhui LuoAbstract:Abstract Topology optimization for energy absorption is studied in this paper. Unlike conventional mean compliance formulation, this paper considers two main functions of vehicle structure: stiffness and energy absorption. During its normal usages, stiffness is chosen as the design objective. During impact, portion of vehicle structures absorbs impact energy while other part maintains the structural integrity. Therefore, we implemented a Regional Strain energy formulation to topology optimization. Sensitivity for Regional Strain energy is derived from the adjoint method. Numerical results from the proposed formulation are presented.
George R. Sutherland - One of the best experts on this subject based on the ideXlab platform.
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Do Regional deformation indexes reflect Regional perfusion in all ischemic substrates
Journal of the American College of Cardiology, 2004Co-Authors: George R. SutherlandAbstract:Ultrasonic Regional Strain (ϵ)/Strain rate (SR) imaging has been shown to be a more sensitive technique for quantifying Regional myocardial deformation compared with other standard cardiac imaging modalities. With its high sampling rate (typically >200 samples/s), it can resolve two parameters that
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Regional Strain and Strain Rate Measurements by Cardiac Ultrasound: Principles, Implementation and Limitations
European journal of echocardiography : the journal of the Working Group on Echocardiography of the European Society of Cardiology, 2000Co-Authors: Jan D'hooge, Paul Suetens, Frank Rademakers, Bart Bijnens, Andreas Heimdal, Fadi Jamal, Tomasz Kukulski, Liv Hatle, George R. SutherlandAbstract:The non-invasive quantification of Regional myocardial function is an important goal in clinical cardiology. Myocardial thickening/thinning indices is one method of attempting to define Regional myocardial function. A new ultrasonic method of quantifying Regional deformation has been introduced based on the principles of ‘Strain’ and ‘Strain rate’ imaging. These new imaging modes introduce concepts derived from mechanical engineering which most echocardiographers are not familiar with. In order to maximally exploit these new techniques, an understanding of what they measure is indispensable. This paper will define each of these modalities in terms of physical principles and will give an introduction to the principles of data acquisition and processing required to implement ultrasonic Strain and Strain rate imaging. In addition, the current status of development of the technique and its limitations will be discussed, together with examples of potential clinical applications.
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REVIEW ARTICLE Regional Strain and Strain Rate Measurements by Cardiac Ultrasound: Principles, Implementation and Limitations
2000Co-Authors: Andreas Heimdal, Paul Suetens, Frank Rademakers, Bart Bijnens, Fadi Jamal, Tomasz Kukulski, Liv Hatle, George R. SutherlandAbstract:The non-invasive quantification of Regional myocardial function is an important goal in clinical cardiology. Myocardial thickening/thinning indices is one method of attempting to define Regional myocardial function. A new ultrasonic method of quantifying Regional deformation has been introduced based on the principles of ‘Strain’ and ‘Strain rate’ imaging. These new imaging modes introduce concepts derived from mechanical engineering which most echocardiographers are not familiar with. In order to maximally exploit these new techniques, an understanding of what they measure is indispensable. This paper will define each of these modalities in terms of physical principles and will give an introduction to the principles of data acquisition and processing required to implement ultrasonic Strain and Strain rate imaging. In addition, the current status of development of the technique and its limitations will be discussed, together with examples of potential clinical applications.
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The response of Regional integrated backscatter levels and Regional Strain to inotropic stimulation and acute ischemia
IEEE Ultrasonics Symposium 2004, 1Co-Authors: Jan D'hooge, Piet Claus, Bart Bijnens, S. Coenen, Oliver Turschner, Myles Mclaughlin, P Mehwald, Maciej Marciniak, M. Dommke, George R. SutherlandAbstract:Integrated backscatter (IB) and its cyclic variation (CVIB) are echocardiographic parameters used for myocardial tissue characterization. The purpose of this study was to examine the potential mechanisms underlying the CVIB. The relationship between changes in integrated backscatter and Regional myocardial Strain was investigated by studying the response of both curves to inotropic stimulation and acute ischemia. Changes in integrated backscatter closely paralleled changes in wall thickening but wall thickening alone could not explain our experimental findings. The results presented in this study further support the hypothesis that changes in tissue reflectivity during the cardiac cycle are induced by Regional myocardial 3D Strain.