While qualitative wall motion analysis has proven valuable in clinical cardiology practice, quantitative analyses remain too time-consuming for routine clinical use. Our long-term goal is therefore to develop automated methods for quantitative wall motion analysis. In this paper, we utilize a finite element model of the regionally ischemic canine left ventricle to demonstrate a new approach based on parameterization of the left ventricular endocardial surface in prolate spheroidal coordinates. The parameterization provided a substantial data reduction and enabled simple definition, calculation, and display of three-dimensional fractional shortening (3DFS), a quantitative measure of wall motion analogous to the fractional shortening measure used in 2D analysis. The endocardial surface area displaying akinesis or dyskinesis by 3DFS corresponded closely to simulated ischemic region size and 3DFS identified appropriate wall motion abnormalities during experimental coronary occlusion in a canine pilot study. 3DFS therefore appears to be a reasonable candidate for clinical tests to determine its utility in identifying and quantifying acute regional ischemia in patients. By linking state of the art finite element models to the clinically relevant framework of wall motion analysis, the methods presented here will facilitate formulation, in silico prescreening, and clinical testing of additional candidate measures of wall motion.
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http://dx.doi.org/10.1007/s10439-005-3312-7 | DOI Listing |
Small Methods
January 2025
Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN, TN 37830, USA.
Understanding ferroelectric domain wall dynamics at the nanoscale across a broad range of timescales requires measuring domain wall position under different applied electric fields. The success of piezoresponse force microscopy (PFM) as a tool to apply local electric fields at different positions and imaging their changing position, together with the information obtained from associated switching spectroscopies has fueled numerous studies of the dynamics of ferroelectric domains to determine the impact of intrinsic parameters such as crystalline order, defects and pinning centers, as well as boundary conditions such as environment. However, the investigation of sub-coercive reversible domain wall vibrational modes requires the development of new tools that enable visualizing domain wall motion under varying applied fields with high temporal and spatial resolution while also accounting for spurious electrostatic effects.
View Article and Find Full Text PDFCardiovasc Diagn Ther
December 2024
Cardiovascular Center, St. Luke's International Hospital, Tokyo, Japan.
Right ventricular (RV) dysfunction after biventricular repair is critical in most adults with congenital heart disease (ACHD). Conventional 2D magnetic resonance imaging (MRI) measurement is considered as a 'gold standard' for RV evaluation; however, addition information on ACHD after biventricular repair is sometimes required. The reasons why adjunctive information is required is as follows: (I) to evaluate the severity of cardiac burden in symptomatic patients with normal RV size and ejection fraction (EF), (II) to determine the optimal timing of invasive treatments in asymptomatic ones, and (III) to detect proactively a potential cardiac burden leading to ventricular deterioration, from a fluid dynamics perspective.
View Article and Find Full Text PDFJ Biomech Eng
January 2025
Department of Mechanical Engineering Marshall University, Huntington, WV 25755, USA; Department of Biomedical Engineering Marshall University, Huntington, WV 25755, USA.
Cell-laden, scaffold-based tissue engineering methods have been successfully utilized for the treatment of bone fractures. In such methods, the rate of scaffold biodegradation, transport of nutrients, and removal of cell metabolic wastes are critical fluid-dynamics factors, affecting tissue regeneration. Therefore, there is a critical need to identify the underlying material transport mechanisms associated with stem cell-driven, scaffold-based bone tissue regeneration.
View Article and Find Full Text PDFElectromagn Biol Med
January 2025
Department of Applied Mathematics, University of Calcutta, Kolkata, India.
The current investigation explores tri-hybrid mediated blood flow through a ciliary annular model, designed to emulate an endoscopic environment. The human circulatory system, driven by the metachronal ciliary waves, is examined in this study to understand how ternary nanoparticles influence wave-like flow dynamics in the presence of interfacial nanolayers. We also analyze the effect of an induced magnetic field on Ag-Cu-/blood flow within the annulus, focusing on thermal radiation, heat sources, buoyancy forces and ciliary motion.
View Article and Find Full Text PDFSci Rep
January 2025
College of Mechanical and Electrical Engineering, Zhoukou Normal University, Zhoukou, 466000, China.
In order to study the movement characteristics of coal particles in the coal loading process of spiral drums, the spiral drum of a certain type of shearer was taken as the research object, and the intrinsic parameters of the materials were calibrated through the determination results of coal sample properties, the relevant parameters of coal particle adhesion were determined, and a discrete element model of spiral drum coal loading was established. The distribution of coal particle movement subsequent to the fracture of the coal wall was derived through simulation. By spatially dividing the envelope region of the spiral drum along the radial and axial directions, the number and velocity distribution of coal particles in different envelope regions were obtained.
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