The effect of anteroapical aneurysm plication on end-systolic three-dimensional strain in the sheep: A magnetic resonance imaging tagging study

Guccione, Julius M.; Walker, Joseph C.; Beitler, Jeremy R.; Moonly, Scott M.; Zhang, Peng; Guttman, Michael A.; Ozturk, Cengizhan; McVeigh, Elliot R.; Wallace, Arthur W.; Saloner, David; Ratcliffe, Mark B.

doi:10.1016/j.jtcvs.2005.07.065

Cited by 21 publications

(21 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Instead, our laboratory recently used cardiac catheterization, magnetic resonance (MR) imaging with myocardial tissue tagging [1], MR diffusion tensor imaging [2], and a finite element (FE) method (developed specifically for cardiac mechanics [3]) to measure regional systolic myocardial material properties in the beating hearts of four sheep with left ventricular (LV) aneurysm [4] and six sheep with LV aneurysm repaired surgically [5]. With knowledge of these myocardial material properties, we were able to quantify the effect of aneurysm plication on regional myocardial stress distributions.…”

Section: Introductionmentioning

confidence: 99%

A Computationally Efficient Formal Optimization of Regional Myocardial Contractility in a Sheep With Left Ventricular Aneurysm

Sun

Stander

Jhun

et al. 2009

Journal of Biomechanical Engineering

Self Cite

129

View full text Add to dashboard Cite

A non-invasive method for estimating regional myocardial contractility in vivo would be of great value in the design and evaluation of new surgical and medical strategies to treat and/or prevent infarction-induced heart failure. As a first step towards developing such a method, an explicit finite element (FE) model-based formal optimization of regional myocardial contractility in a sheep with left ventricular (LV) aneurysm was performed using tagged magnetic resonance (MR) images and cardiac catheterization pressures. From the tagged MR images, 3-dimensional (3D) myocardial strains, LV volumes and geometry for the animal-specific 3D FE model of the LV were calculated, while the LV pressures provided physiological loading conditions. Active material parameters (T max_B and T max_R ) in the non-infarcted myocardium adjacent to the aneurysm (borderzone) and in myocardium remote from the aneurysm were estimated by minimizing the errors between FE model-predicted and measured systolic strains and LV volumes using the successive response surface method for optimization. The significant depression in optimized T max_B relative to T max_R was confirmed by direct ex vivo force measurements from skinned fiber preparations. The optimized values of T max_B and T max_R were not overly sensitive to the passive material parameters specified. The computation time of less than 5 hours associated with our proposed method for estimating regional myocardial contractility in vivo makes it a potentially very useful clinical tool.

show abstract

Section: Introductionmentioning

confidence: 99%

A Computationally Efficient Formal Optimization of Regional Myocardial Contractility in a Sheep With Left Ventricular Aneurysm

Sun

Stander

Jhun

et al. 2009

Journal of Biomechanical Engineering

Self Cite

129

View full text Add to dashboard Cite

show abstract

“…Walker and co-workers [6,7] used cardiac catheterization, three-dimensional MRI with tissue tagging [8], MR diffusion tensor imaging [9], and an FE method (developed specifically for cardiac mechanics [10]) to measure regional systolic myocardial material properties in the beating hearts of four sheep with LV aneurysm [6] and six sheep with LV aneurysm repaired surgically [7]. Although these previous studies [6, 7] represent significant advancements in FE modeling of hearts with myocardial infarction, they both employed a manually directed pseudo-optimization.…”

Section: Introductionmentioning

confidence: 99%

A Novel Method for Quantifying In-Vivo Regional Left Ventricular Myocardial Contractility in the Border Zone of a Myocardial Infarction

Lee

Wenk

Klepach

et al. 2011

Journal of Biomechanical Engineering

Self Cite

View full text Add to dashboard Cite

Homogeneous contractility is usually assigned to the remote region, border zone (BZ) and the infarct in existing infarcted left ventricle (LV) mathematical models. Within the LV, the contractile function is therefore discontinuous. Here, we hypothesize that the BZ may in fact define a smooth linear transition in contractility between the remote region and the infarct. To test this hypothesis, we developed a mathematical model of a sheep LV having an anteroapical infarct with linearly–varying BZ contractility. Using an existing optimization method [1], we use that model to extract active material parameter Tmax and BZ width dn that “best” predict in–vivo systolic strain fields measured from tagged magnetic resonance images (MRI). We confirm our hypothesis by showing that our model, compared to one that has homogeneous contractility assigned in each region, reduces the mean square errors between the predicted and the measured strain fields. Because the peak fiber stress differs significantly (~ 15%) between these two models, our result suggests that future mathematical LV models, particularly those used to analyse myocardial infarction treatment, should account for a smooth linear transition in contractility within the BZ.

show abstract

“…With use of radio-frequency (RF) pulse to alter the local magnetic properties of the tissue, tagged MRI generates grid lines that are embedded in the myocardium (26). By tracing the deformation of the tag lines recorded in cine images, myocardial displacement can be recovered (10,11). Phase-contrast MRI has also been developed to measure the instantaneous velocity field in the myocardium (17,22).…”

mentioning

confidence: 99%

Reconstruction of myocardial tissue motion and strain fields from displacement-encoded MR imaging

Liu¹,

Wen²,

Gorman³

et al. 2009

American Journal of Physiology-Heart and Circulatory Physiology

View full text Add to dashboard Cite

A quantitative analysis of myocardial mechanics is fundamental to understanding cardiac function, diagnosis of heart disease, and assessment of therapeutic intervention. Displacement encoding with stimulated-echo (DENSE) magnetic resonance imaging (MRI) technique was developed to track the three-dimensional (3D) displacement vector of discrete material grid points in the myocardial tissue. Despite the wealth of information gained from DENSE images, the current software only provides two-dimensional in-plane deformation. The objective of this study is to introduce a postprocessing method to reconstruct and visualize continuous dynamic 3D displacement and strain fields in the ventricular wall from DENSE data. An anatomically accurate hexagonal finite-element model of the left ventricle (LV) is reconstructed by fitting a prolate spheroidal primitive to contour points of the epi- and endocardial surfaces. The continuous displacement field in the model is described mathematically based on the discrete DENSE vectors using a minimization method with smoothness regularization. Based on the displacement, heart motion and myocardial stretch (or strain) are analyzed. Illustratory computations were conducted with DENSE data of three infarcted and one normal sheep ventricles. The full 3D results show stronger overall axial shortening, wall thickening, and twisting of the normal LV compared with the infarcted hearts. Local myocardial stretches show a dyskinetic LV in the apical region, dilation of apex in systole, and a compensatory increase in strain in the healthy basal region as a compensatory mechanism. We conclude that the proposed postprocessing method significantly extends the utility of DENSE MRI, which may provide a patient-specific 3D model of cardiac mechanics.

show abstract

The effect of anteroapical aneurysm plication on end-systolic three-dimensional strain in the sheep: A magnetic resonance imaging tagging study

Abstract: Repair of left ventricular aneurysm significantly increases systolic circumferential shortening at the border zone in sheep.

Cited by 21 publications

References 17 publications

A Computationally Efficient Formal Optimization of Regional Myocardial Contractility in a Sheep With Left Ventricular Aneurysm

A Computationally Efficient Formal Optimization of Regional Myocardial Contractility in a Sheep With Left Ventricular Aneurysm

A Novel Method for Quantifying In-Vivo Regional Left Ventricular Myocardial Contractility in the Border Zone of a Myocardial Infarction

Reconstruction of myocardial tissue motion and strain fields from displacement-encoded MR imaging

Contact Info

Product

Resources

About