In engineering, optimizing parameters often involves computationally expensive tasks, especially when dealing with multi-dimensional variables and multiple performance metrics. This falls under the category of multi-objective black-box optimization. To address this, we propose two optimization algorithms for low and medium-dimensional spaces, incorporating relaxation conditions for hyperplane segmentation.
View Article and Find Full Text PDFEur Heart J Imaging Methods Pract
July 2024
Aims: A new model of computational fluid dynamics (CFD)-based algorithm for coronary CT angiography (CCTA)-derived fractional flow reserve (FFR) (CT-FFR) analysis by expanding the coronary tree to smaller-diameter lumen (0.8 mm) using Newton-Krylov-Schwarz (NKS) method to solve the three-dimensional time-dependent incompressible Navier-Stokes equations has been developed; however, the diagnostic performance of this new method has not been sufficiently investigated. The aim of this study was to determine the diagnostic performance of a novel CT-FFR technique by expanding the coronary tree in the CFD domain.
View Article and Find Full Text PDFBackground: Superficial temporal artery (STA)-middle cerebral artery (MCA) bypass surgery has been widely adopted in treating moyamoya disease (MMD). Geometric variations including high tortuosity and stenosis exist in many cases, but the hemodynamic effects have not been comprehensively evaluated. We aim to evaluate the hemodynamic effects of bypass geometry variations based on patient-specific data.
View Article and Find Full Text PDFObjective: To evaluate the clinical outcomes of reverse total shoulder arthroplasty as a revision procedure for the failed fixation of proximal humeral fractures in the elderly patients.
Methods: A retrospective analysis was performed on 8 patients with failed internal fixation of proximal humeral fractures from May 2014 to March 2020, including 3 males and 5 females, aged from 65 to 75 years old. All 8 patients underwent reverse total shoulder arthroplasty, and the mean time between initial fixation and reverse total shoulder arthroplasty ranged from 8 to 16 months.
Objective: Noninvasive fractional flow reserve (FFR) has been extensively studied and gained clinical recognition. However, the effect of an interventional catheter and a pressure wire in the arteries on the noninvasive FFR was not considered in previous studies. We provide quantitative analysis of how a catheter and a pressure wire can affect the estimation of noninvasive FFR using computational fluid dynamics (CFD) techniques.
View Article and Find Full Text PDFIntroduction: Accurate and rapid assessment of the coronary microcirculation has become an important medical challenge. However, reliable and non-invasive quantitative methods to diagnose coronary microvascular disease (CMVD), select treatments for coronary artery disease (CAD), and therefore improve coronary microcirculation are lacking. Current detection methods have limitations.
View Article and Find Full Text PDFComput Methods Programs Biomed
September 2022
Background: An efficient and accurate blood flow simulation can be useful for understanding many vascular diseases. Accurately resolving the blood flow velocity based on patient-specific geometries and model parameters is still a major challenge because of complex geomerty and turbulence issues. In addition, obtaining results in a short amount of computing time is important so that the simulation can be used in the clinical environment.
View Article and Find Full Text PDFCharcot arthropathy is a type of destructive osteoarthropathy characterized by neurotrophic and sensory disorders. The condition is relatively rare, with an insidious onset, and it is easily misdiagnosed. Total knee arthroplasty (TKA) can cause excessive joint wear, continuous inflammatory stimulation of the prosthesis, postoperative residual cavity, prosthesis loosening and subsidence, peripheral fracture, infection, and other complications.
View Article and Find Full Text PDFBackground: Cerebral hemodynamic disorders are involved in the occurrence and progression of vascular dementia (VaD), but the methods to detect hemodynamics remainmultifarious and uncertain nowadays. We aim to exploit a computational fluid dynamics (CFD) approach by static and dynamic parameters, which can be used to detect individual cerebrovascular hemodynamics quantitatively.
Methods: A patient-specific CFD model was constructed with geometrical arteries on the magnetic resonance angiography (MRA) and hemodynamic parameters on ultrasound Doppler, by which, the structural and simulated hemodynamic indexes could be obtained, mainly including the cerebral arterial volume (CAV), the number of visible arterial outlets, the total cerebral blood flow (tCBF) index and the total cerebrovascular resistance (tCVR) index.
Partial differential equations (PDEs) are ubiquitous in natural science and engineering problems. Traditional discrete methods for solving PDEs are usually time-consuming and labor-intensive due to the need for tedious mesh generation and numerical iterations. Recently, deep neural networks have shown new promise in cost-effective surrogate modeling because of their universal function approximation abilities.
View Article and Find Full Text PDFSurgical planning for aortic aneurysm repair is a difficult task. In addition to the morphological features obtained from medical imaging, alternative features obtained with computational modeling may provide additional useful information. Though numerical studies are noninvasive, they are often time-consuming, especially when we need to study and compare multiple repair scenarios, because of the high computational complexity.
View Article and Find Full Text PDFObjectives: We attempted to improve the accuracy of coronary CT angiography (CCTA)-derived fractional flow reserve (FFR) (FFR) by expanding the coronary tree in the computational fluid dynamics (CFD) domain. An observational study was performed to evaluate the effects of extending the coronary tree analysis for FFR from a minimal diameter of 1.2 to 0.
View Article and Find Full Text PDFIn this paper, a finite-volume discrete Boltzmann method based on a cell-centered scheme for inviscid compressible flows on unstructured grids is presented. In the new method, the equilibrium distribution functions are obtained from the circle function in two-dimensions (2D) and the spherical function in three-dimensions (3D). Moreover, the advective fluxes are evaluated by Roe's flux-difference splitting scheme, the gradients of the density and total energy distribution functions are computed with a least-squares method, and the Venkatakrishnan limiter is employed to prevent oscillations.
View Article and Find Full Text PDFInt J Numer Method Biomed Eng
June 2021
Computational hemodynamics is being developed as an alternative approach for assisting clinical diagnosis and treatment planning for liver diseases. The technology is non-invasive, but the computational time could be high when the full geometry of the blood vessels is taken into account. Existing approaches use either one-dimensional model of the artery or simplified three-dimensional tubular geometry in order to reduce the computational time, but the accuracy is sometime compromised, for example, when simulating blood flows in arteries with plaque.
View Article and Find Full Text PDFBiomech Model Mechanobiol
June 2021
The abdominal aorta is the largest artery in the abdominal cavity that supplies blood flows to vital organs through the complex visceral arterial branches, including the celiac trunk (the liver, stomach, spleen, etc.), the renal arteries (the kidneys) and the superior and inferior mesenteric arteries (the small and large intestine, pancreas, etc.).
View Article and Find Full Text PDFBackground: The sustained negative pressure created by vacuum sealing drainage (VSD) on exposed vascular wounds can result in blood vessel compression, embolism, or necrosis. The objective of this research was to explore the ability of an experimental vascular protective shield combined with VSD to protect exposed vessels of the lower limbs and accelerate wound repair.
Methods: (I) The vascular protective shield was prepared; (II) the material was subjected to acute toxicity and hemolysis tests; (III) and 30 New Zealand rabbits were divided into three groups: the control, VSD-only, and combined shield-VSD groups (with ten rabbits in each group).
Int J Numer Method Biomed Eng
November 2020
Numerical simulation of blood flows in patient-specific arteries can be useful for the understanding of vascular diseases, as well as for surgery planning. In this paper, we simulate blood flows in the full cerebral artery of stroke patients. To accurately resolve the flow in this rather complex geometry with stenosis is challenging and it is also important to obtain the results in a short amount of computing time so that the simulation can be used in pre- and/or post-surgery planning.
View Article and Find Full Text PDFBackground: Many studies have confirmed that electroacupuncture can regulate the body's environment to treat a variety of diseases. However, there are few reports on the mechanism of electroacupuncture therapy for diseases involving skin injury. Transcriptome sequencing can reveal changes in gene expression within cells and the signaling pathways involved.
View Article and Find Full Text PDFObjective: To explore clinical effect of high strength wire under arthroscopy combined with outside anchor nail in treating Meyers McKeever II, III anterior cruciate ligament tibial check point.
Methods: From March 2014 to June 2016, 21 patients with Meyers McKeever II, III avulsion fracture of anterior cruciate ligament tibial check point were treated by high strength wire under arthroscopy combined outside anchor nail. There were 13 males and 8 females aged from 18 to 48 years old with an average of (26.
Evid Based Complement Alternat Med
July 2019
The mitogen-activated protein kinase (MAPK) signal transduction pathway plays an important role in the regulation of various diseases, such as cardiovascular and cerebrovascular diseases, and takes part in anti-inflammatory effects, analgesic effects, protection against injury, and maintenance of gastrointestinal functions. Electroacupuncture therapy is an external therapy used in traditional Chinese medicine. By adding external electrical stimulation to traditional acupuncture, the stimulus gets doubled and the therapeutic efficacy gets enhanced accordingly.
View Article and Find Full Text PDFThe fractional pressure ratio is introduced to quantitatively assess the hemodynamic significance of severe intracranial stenosis. A computational fluid dynamics-based method is proposed to non-invasively compute the FPR and compared against fractional pressure ratio measured by an invasive technique. Eleven patients with severe intracranial stenosis considered for endovascular intervention were recruited and an invasive procedure was performed to measure the distal and the aortic pressure ( P and P).
View Article and Find Full Text PDFObjective: To compare clinical outcomes of minimally invasive percutaneous plate osteosynthesis (MIPPO) in treating distal tibial comminuted fractures at early and delayed stage.
Methods: From January 2006 to January 2012,66 patients with distal tibial comminuted fractures were treated by MIPPO. All patients were divided into primary group and delayed group according to operation time.
Objective: To observe the effect of elongated-needle penetration (ENP) stimulation of "Zhibian" (BL 54), "Shuidao" (ST 28), "Qihai" (CV 6) and "Zhongji" (CV 3) on spinal nerve cell apoptosis and cellular signal transduction in spinal cord injury rabbits, so as to reveal its mechanism underlying improvement of spinal injury.
Methods: A total of 80 adult Newzealand rabbits were randomized to control, model, ENP, ENP + LY 294002 (PI3K antagonist), ENP + PD 98059 (MEK antagonist) groups, with 16 rabbits in each group. The spinal cord injury model was established by using modified Allen's method (Gravity-drop device).