1
|
Pinto MD, Pinto RS, Nosaka K, Blazevich AJ. Response. Med Sci Sports Exerc 2024; 56:1210-1212. [PMID: 38350460 DOI: 10.1249/mss.0000000000003401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2024]
|
2
|
Shvets DA, Povetkin SV. Limitations of Diagnosis of Ischemic Left Ventricular Dysfunction Using the Values of Strain, Twist and Untwist in Patients With Myocardial Infarction of Various Localization. KARDIOLOGIIA 2024; 64:55-62. [PMID: 38597763 DOI: 10.18087/cardio.2024.3.n2253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 09/16/2022] [Indexed: 04/11/2024]
Abstract
AIM To compare capabilities for diagnosing regional and global myocardial dysfunction using the values of longitudinal and circular strain, left ventricular (LV) torsion and untwisting in patients with myocardial infarction (MI) of various locations. MATERIAL AND METHODS Patients included in the study (n=121) were divided into three groups: patients with unstable angina (n=30), patients with anterior MI (n=45), and patients with inferior MI (n=46). Clinical, laboratory and instrumental test were performed, including echocardiography. For a quantitative analysis of LV contractility, the maximum systolic peaks of regional and global longitudinal and circular strain, systolic and diastolic rotation, LV torsion and untwisting were measured. RESULTS Anterior MI was characterized by injury of the LV apical segments, while inferior MI was characterized by injury of the basal segments. In anterior MI, the longitudinal strain was reduced less than 14.5% and circular strain less than 19.3% in the apical segment of the LV anteroseptal wall (ASW). In akinesia of the LV ASW apical segment, longitudinal and circular strains were reduced less than 10%. The magnitude of the circular strain of the LV ASW apical segment (diagnostic threshold 19.3%, sensitivity (Se) 87%, specificity (Sp) 90%) was superior to that of the longitudinal strain as a diagnostic marker for regional ischemic dysfunction in anterior MI. The magnitude of the circular strain of the basal segment of the LV inferior wall in inferior MI has a greater diagnostic value for identifying regional systolic dysfunction than the value of the longitudinal strain of this LV segment. The diagnostic threshold was 17.3%, Se 79%, Sp 80%. CONCLUSION A decrease in the circular strain of the LV ASW less than 19.3% in the LV apical segment is more specific (Sp 90%) for diagnosing regional systolic dysfunction in anterior MI than a decrease in longitudinal strain. A circular strain value of less than 17.3% in the basal segment of the LV inferior wall is more specific (Sp 80%) than the longitudinal strain of this segment for diagnosing regional systolic dysfunction in inferior MI. Predominant injury to the LV apex in anterior MI can cause systolic and diastolic myocardial dysfunction, which is manifested by a decrease in LV circular deformation, torsion and untwisting.
Collapse
|
3
|
Pittman LA, Whittaker P, Milne ML, Chung CS. Collagenase treatment reduces the anisotropy of ultrasonic backscatter in rat myocardium by reducing collagen crosslinks. Physiol Rep 2023; 11:e15849. [PMID: 37960992 PMCID: PMC10643982 DOI: 10.14814/phy2.15849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 10/19/2023] [Accepted: 10/19/2023] [Indexed: 11/15/2023] Open
Abstract
Dysregulation of collagen deposition, degradation, and crosslinking in the heart occur in response to increased physiological stress. Collagen content has been associated with ultrasonic backscatter (brightness), and we have shown that the anisotropy of backscatter can be used to measure myofiber alignment, that is, variation in the brightness of a left ventricular short-axis ultrasound. This study investigated collagen's role in anisotropy of ultrasonic backscatter; female Sprague-Dawley rat hearts were treated with a collagenase-containing solution, for either 10 or 30 min, or control solution for 30 min. Serial ultrasound images were acquired at 2.5-min intervals throughout collagenase treatment. Ultrasonic backscatter was assessed from anterior and posterior walls, where collagen fibrils are predominately aligned perpendicular to the angle of insonification, and the lateral and septal walls, where collagen is predominately aligned parallel to the angle of insonification. Collagenase digestion reduced backscatter anisotropy within the myocardium. Collagen remains present in the myocardium throughout collagenase treatment, but crosslinking is altered within 10 min. These data suggest that crosslinking of collagen modulates the anisotropy of ultrasonic backscatter. An Anisotropy Index, derived from differences in backscatter from parallel and perpendicularly aligned fibers, may provide a noninvasive index to monitor the progression and state of myocardial fibrosis.
Collapse
Affiliation(s)
| | | | - Michelle L. Milne
- Department of PhysicsSt Mary's College of MarylandSt Mary's CityMarylandUSA
| | - Charles S. Chung
- Department of PhysiologyWayne State UniversityDetroitMichiganUSA
| |
Collapse
|
4
|
Martonová D, Holz D, Duong MT, Leyendecker S. Smoothed finite element methods in simulation of active contraction of myocardial tissue samples. J Biomech 2023; 157:111691. [PMID: 37441914 DOI: 10.1016/j.jbiomech.2023.111691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 05/12/2023] [Accepted: 06/14/2023] [Indexed: 07/15/2023]
Abstract
In modelling and simulation of cardiac mechanics, tetrahedral meshes are often used due to the easy availability of efficient meshing algorithms. This is beneficial in particular when complex geometries such as cardiac structures are considered. The gold standard in simulating the cardiac cycle is to solve the mechanical balance equations with the finite element method (FEM). However, using linear shape functions in the FEM in combination with nearly-incompressible material models is known to produce overly stiff approximations, whereas higher order elements are computationally more expensive. To overcome these problems, smoothed finite element methods (S-FEMs) have been proposed by Liu and co-workers. So far, S-FEMs in 3D have been utilised only in simulations of passive mechanics. In the present work, different S-FEMs are for the first time used for simulation of an active cardiac contraction on three-dimensional myocardial tissue samples. Further, node-based S-FEM (NS-FEM), face-based S-FEM (FS-FEM) and selective FS/NS-FEM are for the first time implemented as user subroutine in the commercial software Abaqus. Our results confirm that all S-FEMs perform softer than linear FEM and volumetric locking is reduced. The FS/NS-FEM produces solutions with the relative error in maximum displacement and rotation being less than 5% with respect to the reference solution obtained by the quadratic FEM for all considered mesh sizes, although linear shape functions are used. We therefore conclude that in particular FS/NS-FEM is an efficient and accurate numerical method in the simulation of an active cardiac muscle contraction.
Collapse
Affiliation(s)
- Denisa Martonová
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Applied Dynamics, Immerwahrstraße 1, 91058 Erlangen, Germany.
| | - David Holz
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Applied Dynamics, Immerwahrstraße 1, 91058 Erlangen, Germany
| | - Minh Tuan Duong
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Applied Dynamics, Immerwahrstraße 1, 91058 Erlangen, Germany; School of Mechanical Engineering, Hanoi University of Science and Technology, 1 DaiCoViet Road, Hanoi, Vietnam
| | - Sigrid Leyendecker
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Applied Dynamics, Immerwahrstraße 1, 91058 Erlangen, Germany
| |
Collapse
|
5
|
Martonová D, Holz D, Seufert J, Duong MT, Alkassar M, Leyendecker S. Comparison of stress and stress–strain approaches for the active contraction in a rat cardiac cycle model. J Biomech 2022; 134:110980. [DOI: 10.1016/j.jbiomech.2022.110980] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 01/21/2022] [Accepted: 01/24/2022] [Indexed: 11/17/2022]
|
6
|
Kovacheva E, Thämer L, Fritz T, Seemann G, Ochs M, Dössel O, Loewe A. Estimating cardiac active tension from wall motion-An inverse problem of cardiac biomechanics. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2021; 37:e3448. [PMID: 33606343 DOI: 10.1002/cnm.3448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 12/21/2020] [Accepted: 02/06/2021] [Indexed: 06/12/2023]
Abstract
The contraction of the human heart is a complex process as a consequence of the interaction of internal and external forces. In current clinical routine, the resulting deformation can be imaged during an entire heart beat. However, the active tension development cannot be measured in vivo but may provide valuable diagnostic information. In this work, we present a novel numerical method for solving an inverse problem of cardiac biomechanics-estimating the dynamic active tension field, provided the motion of the myocardial wall is known. This ill-posed non-linear problem is solved using second order Tikhonov regularization in space and time. We conducted a sensitivity analysis by varying the fiber orientation in the range of measurement accuracy. To achieve RMSE <20% of the maximal tension, the fiber orientation needs to be provided with an accuracy of 10°. Also, variation was added to the deformation data in the range of segmentation accuracy. Here, imposing temporal regularization led to an eightfold decrease in the error down to 12%. Furthermore, non-contracting regions representing myocardial infarct scars were introduced in the left ventricle and could be identified accurately in the inverse solution (sensitivity >0.95). The results obtained with non-matching input data are promising and indicate directions for further improvement of the method. In future, this method will be extended to estimate the active tension field based on motion data from clinical images, which could provide important insights in terms of a new diagnostic tool for the identification and treatment of diseased heart tissue.
Collapse
Affiliation(s)
- Ekaterina Kovacheva
- Institute of Biomedical Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Laura Thämer
- Institute of Biomedical Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Thomas Fritz
- Institute of Biomedical Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
- Department of Cardiology, University Hospital Heidelberg, Heidelberg, Germany
| | - Gunnar Seemann
- Institute of Biomedical Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg, Bad Krozingen, Medical Center, University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Marco Ochs
- Department of Cardiology, University Hospital Heidelberg, Heidelberg, Germany
| | - Olaf Dössel
- Institute of Biomedical Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Axel Loewe
- Institute of Biomedical Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| |
Collapse
|
7
|
Martonová D, Alkassar M, Seufert J, Holz D, Dương MT, Reischl B, Friedrich O, Leyendecker S. Passive mechanical properties in healthy and infarcted rat left ventricle characterised via a mixture model. J Mech Behav Biomed Mater 2021; 119:104430. [PMID: 33780851 DOI: 10.1016/j.jmbbm.2021.104430] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 02/21/2021] [Accepted: 02/22/2021] [Indexed: 11/29/2022]
Abstract
During the cardiac cycle, electrical excitation is coupled with mechanical response of the myocardium. Besides the active contraction, passive mechanics plays an important role, and its behaviour differs in healthy and diseased hearts as well as among different animal species. The aim of this study is the characterisation of passive mechanical properties in healthy and infarcted rat myocardium by means of mechanical testing and subsequent parameter fitting. Elasticity assessments via uniaxial extension tests are performed on healthy and infarcted tissue samples from left ventricular rat myocardium. In order to fully characterise the orthotropic cardiac tissue, our experimental data are combined with other previously published tests in rats - shear tests on healthy myocardium and equibiaxial tests on infarcted tissue. In a first step, we calibrate the Holzapfel-Ogden strain energy function in the healthy case. Sa far, this orthotropic constitutive law for the passive myocardium has been fitted to experimental data in several species, however there is a lack of an appropriate parameter set for the rat. With our determined parameters, a finite element simulation of the end-diastolic filling is performed. In a second step, we propose a model for the infarcted tissue. It is represented as a mixture of intact myocardium and a transversely isotropic scar structure. In our mechanical experiments, the tissue after myocardial infarction shows significantly stiffer behaviour than in the healthy case, and the stiffness correlates with the amount of fibrosis. A similar relationship is observed in the computational simulation of the end-diastolic filling. We conclude that our new proposed material model can capture the behaviour of two kinds of tissues - healthy and infarcted rat myocardium, and its calibration with the fitted parameters represents the experimental data well.
Collapse
Affiliation(s)
- Denisa Martonová
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Applied Dynamics, Immerwahrstraße 1, 91058 Erlangen, Germany.
| | - Muhannad Alkassar
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Pediatric Cardiology, Loschgestraße 15, 91054 Erlangen, Germany
| | - Julia Seufert
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Pediatric Cardiology, Loschgestraße 15, 91054 Erlangen, Germany
| | - David Holz
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Applied Dynamics, Immerwahrstraße 1, 91058 Erlangen, Germany
| | - Minh Tuấn Dương
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Applied Dynamics, Immerwahrstraße 1, 91058 Erlangen, Germany; School of Mechanical Engineering, Hanoi University of Science and Technology, 1 DaiCoViet Road, Hanoi, Vietnam
| | - Barbara Reischl
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Medical Biotechnology, Paul-Gordan-Str. 3, 91052 Erlangen, Germany
| | - Oliver Friedrich
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Medical Biotechnology, Paul-Gordan-Str. 3, 91052 Erlangen, Germany
| | - Sigrid Leyendecker
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Applied Dynamics, Immerwahrstraße 1, 91058 Erlangen, Germany
| |
Collapse
|
8
|
Yociss M, Fei B. GPU-Based Simulation of Echocardiography Volumes Using Quantitative Fiber-Angle-to-Backscatter Measurements. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2021; 11602:116020U. [PMID: 35756345 PMCID: PMC9232193 DOI: 10.1117/12.2581962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The intensity of backscattered ultrasound signal from heart muscle is known to be related to the angle between cardiac fibers and the insonification direction. In this work, a GPU-based method of simulating three-dimensional (3D) echocardiographic images from an empirically derived angle-to-backscatter relationship is developed and validated. Images of a rotating fiber phantom are simulated, and it is validated that the angle-to-backscatter relationship is accurately reflected by the simulated envelope data. In a second experiment, echocardiography images are simulated from a diffusion tensor magnetic resonance imaging (DT-MRI) volume of a canine heart to demonstrate that the method produces view-dependent speckle. 3D volumes of a parametrically generated ideal left ventricle phantom are also simulated and processed into fiber orientation maps using the underlying quantitative parameters. Images are simulated based on the characteristics of a 35-by-32 two-dimensional (2D) matrix array probe and a clinical one-dimensional (1D) phased array probe. The processed fiber volumes exhibit good agreement with the virtual phantom's ground truth, having an average acute angle error (AAE) of less than 10 degrees for both probes. The simulation method is fast and opens a new approach for ultrasound fiber imaging.
Collapse
Affiliation(s)
- Megan Yociss
- The University of Texas at Dallas, Department of Bioengineering, Richardson, TX
| | - Baowei Fei
- The University of Texas at Dallas, Department of Bioengineering, Richardson, TX
- The University of Texas Southwestern Medical Center, Department of Radiology, Dallas, TX
| |
Collapse
|