scholarly journals From 4D Medical Images (CT, MRI, and Ultrasound) to 4D Structured Mesh Models of the Left Ventricular Endocardium for Patient-Specific Simulations

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Federico Canè ◽  
Benedict Verhegghe ◽  
Matthieu De Beule ◽  
Philippe B. Bertrand ◽  
Rob J. Van der Geest ◽  
...  
Keyword(s):  
Medical Images ◽  
Left Ventricular ◽  
Moving Boundaries ◽  
Patient Specific ◽  
Diagnostic Tools ◽  
Future Research ◽  
Ct Reconstruction ◽  
Cfd Simulations ◽  
High Quality ◽  
Mesh Models

With cardiovascular disease (CVD) remaining the primary cause of death worldwide, early detection of CVDs becomes essential. The intracardiac flow is an important component of ventricular function, motion kinetics, wash-out of ventricular chambers, and ventricular energetics. Coupling between Computational Fluid Dynamics (CFD) simulations and medical images can play a fundamental role in terms of patient-specific diagnostic tools. From a technical perspective, CFD simulations with moving boundaries could easily lead to negative volumes errors and the sudden failure of the simulation. The generation of high-quality 4D meshes (3D in space + time) with 1-to-1 vertex becomes essential to perform a CFD simulation with moving boundaries. In this context, we developed a semiautomatic morphing tool able to create 4D high-quality structured meshes starting from a segmented 4D dataset. To prove the versatility and efficiency, the method was tested on three different 4D datasets (Ultrasound, MRI, and CT) by evaluating the quality and accuracy of the resulting 4D meshes. Furthermore, an estimation of some physiological quantities is accomplished for the 4D CT reconstruction. Future research will aim at extending the region of interest, further automation of the meshing algorithm, and generating structured hexahedral mesh models both for the blood and myocardial volume.

Estimation of left ventricular blood flow parameters: clinical application of patient-specific CFD simulations from 4D echocardiography

2017 ◽  
Author(s):  
David Larsson ◽  
Jeannette H. Spühler ◽  
Elif Günyeli ◽  
Tino Weinkauf ◽  
Johan Hoffman ◽  
...  
Keyword(s):  
Blood Flow ◽  
Clinical Application ◽  
Left Ventricular ◽  
Patient Specific ◽  
Cfd Simulations ◽  
Flow Parameters

scholarly journals Left Ventricular Flow Analysis: Recent Advances in Numerical Methods and Applications in Cardiac Ultrasound

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Iman Borazjani ◽  
John Westerdale ◽  
Eileen M. McMahon ◽  
Prathish K. Rajaraman ◽  
Jeffrey J. Heys ◽  
...  
Keyword(s):  
Heart Valves ◽  
Flow Analysis ◽  
Systemic Circulation ◽  
Left Ventricular ◽  
The Body ◽  
Patient Specific ◽  
Future Research ◽  
Prognostic Information ◽  
Flow Measurements ◽  
Recent Advances

The left ventricle (LV) pumps oxygenated blood from the lungs to the rest of the body through systemic circulation. The efficiency of such a pumping function is dependent on blood flow within the LV chamber. It is therefore crucial to accurately characterize LV hemodynamics. Improved understanding of LV hemodynamics is expected to provide important clinical diagnostic and prognostic information. We review the recent advances in numerical and experimental methods for characterizing LV flows and focus on analysis of intraventricular flow fields by echocardiographic particle image velocimetry (echo-PIV), due to its potential for broad and practical utility. Future research directions to advance patient-specific LV simulations include development of methods capable of resolving heart valves, higher temporal resolution, automated generation of three-dimensional (3D) geometry, and incorporating actual flow measurements into the numerical solution of the 3D cardiovascular fluid dynamics.

Cardiac Resynchronisation Therapy – Evolving Strategies to Enhance Response

2010 ◽  
Vol 6 (1) ◽  
pp. 83
Author(s):  
Jagmeet P Singh ◽  
Keyword(s):  
Heart Failure ◽  
Systolic Heart Failure ◽  
Cardiac Resynchronisation Therapy ◽  
Left Ventricular ◽  
Patient Specific ◽  
Cardiac Resynchronisation ◽  
Clinical Benefits ◽  
Pacing Lead ◽  
Resynchronisation Therapy ◽  
Physiological Impact

Cardiac resynchronisation therapy (CRT) has gained widespread acceptance as a safe and effective therapeutic strategy for congestive heart failure (CHF) refractory to optimal medical therapy. The use of implantable devices has substantially altered the natural history of systolic heart failure. These devices exert their physiological impact through ventricular remodelling, associated with a reduction in left ventricular (LV) volumes and an improvement in ejection fraction (EF). Several prospective randomised studies have shown that this in turn translates into long-term clinical benefits such as improved quality of life, increased functional capacity and reduction in hospitalisation for heart failure and overall mortality. Despite these obvious benefits, there remain more than a few unresolved concerns, the most important being that up to one-third of patients treated with CRT do not derive any detectable benefit. There are several determinants of successful delivery and response to CRT, including selecting the appropriate patient, patient-specific optimal LV pacing lead placement and appropriate post-implant device care and follow-up. This article highlights the importance of collectively working on all of these aspects of CRT to enhance and maximise response.

The psychology of offering an apology: Understanding the barriers to apologizing and how to overcome them

2017 ◽  
Author(s):  
Karina Schumann
Keyword(s):  
Future Research ◽  
Perceived Threat ◽  
High Quality ◽  
Important Decision ◽  
Self Image

After committing an offense, a transgressor faces an important decision regarding whether and how to apologize to the person who was harmed. The actions he or she chooses to take after committing an offense can have dramatic implications for the victim, the transgressor, and their relationship. Although high quality apologies are extremely effective at promoting reconciliation, transgressors often choose to offer a perfunctory apology, withhold an apology, or respond defensively to the victim. Why might this be? In this article, I propose three major barriers to offering high quality apologies: (1) low concern for the victim or relationship, (2) perceived threat to self-image, and (3) perceived apology ineffectiveness. I review recent research examining how these barriers affect transgressors’ apology behavior, and describe insights this emerging work provides for developing methods to move transgressors towards more reparative behavior. Finally, I discuss important directions for future research.

Biomarkers of Atrial Fibrillation in Hypertension

2019 ◽  
Vol 26 (5) ◽  
pp. 888-897 ◽  
Author(s):  
Costas Tsioufis ◽  
Dimitris Konstantinidis ◽  
Ilias Nikolakopoulos ◽  
Evi Vemmou ◽  
Theodoros Kalos ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Left Ventricular ◽  
P Wave ◽  
Diagnostic Tools ◽  
Atrial Remodeling ◽  
Hypertensive Patients ◽  
Risk Patients ◽  
Underlying Mechanisms ◽  
Prompt Diagnosis ◽  
The Ideal

Background: Atrial fibrillation (AF) is the most frequently encountered cardiac arrhythmia globally and substantially increases the risk for thromboembolic disease. Albeit, 20% of all cases of AF remain undiagnosed. On the other hand, hypertension amplifies the risk for both AF occurrences through hemodynamic and non-hemodynamic mechanisms and cerebrovascular ischemia. Under this prism, prompt diagnosis of undetected AF in hypertensive patients is of pivotal importance. Method: We conducted a review of the literature for studies with biomarkers that could be used in AF diagnosis as well as in predicting the transition of paroxysmal AF to sustained AF, especially in hypertensive patients. Results: Potential biomarkers for AF can be broadly categorized into electrophysiological, morphological and molecular markers that reflect the underlying mechanisms of adverse atrial remodeling. We focused on P-wave duration and dispersion as electrophysiological markers, and left atrial (LA) and LA appendage size, atrial fibrosis, left ventricular hypertrophy and aortic stiffness as structural biomarkers, respectively. The heterogeneous group of molecular biomarkers of AF encompasses products of the neurohormonal cascade, including NT-pro BNP, BNP, MR-pro ANP, polymorphisms of the ACE and convertases such as corin and furin. In addition, soluble biomarkers of inflammation (i.e. CRP, IL-6) and fibrosis (i.e. TGF-1 and matrix metalloproteinases) were assessed for predicting AF. Conclusion: The reviewed individual biomarkers might be a valuable addition to current diagnostic tools but the ideal candidate is expected to combine multiple indices of atrial remodeling in order to effectively detect both AF and adverse characteristics of high risk patients with hypertension.

Recognition of Fungal Components by the Host Immune System

2020 ◽  
Vol 21 (3) ◽  
pp. 245-264 ◽  
Author(s):  
Laura C. García-Carnero ◽  
José A. Martínez-Álvarez ◽  
Luis M. Salazar-García ◽  
Nancy E. Lozoya-Pérez ◽  
Sandra E. González-Hernández ◽  
...  
Keyword(s):  
Immune System ◽  
Histoplasma Capsulatum ◽  
Paracoccidioides Brasiliensis ◽  
Sporothrix Schenckii ◽  
Clinical Importance ◽  
Pathogenic Fungi ◽  
Diagnostic Tools ◽  
Future Research ◽  
Host Immune System ◽  
Fungal Antigens

: By being the first point of contact of the fungus with the host, the cell wall plays an important role in the pathogenesis, having many molecules that participate as antigens that are recognized by immune cells, and also that help the fungus to establish infection. The main molecules reported to trigger an immune response are chitin, glucans, oligosaccharides, proteins, melanin, phospholipids, and others, being present in the principal pathogenic fungi with clinical importance worldwide, such as Histoplasma capsulatum, Paracoccidioides brasiliensis, Aspergillus fumigatus, Candida albicans, Cryptococcus neoformans, Blastomyces dermatitidis, and Sporothrix schenckii. Knowledge and understanding of how the immune system recognizes and responds to fungal antigens are relevant for the future research and development of new diagnostic tools and treatments for the control of mycosis caused by these fungi.

scholarly journals Optimization of Plasmodium vivax sporozoite production from Anopheles stephensi in South West India

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Ajeet Kumar Mohanty ◽  
Charles de Souza ◽  
Deepika Harjai ◽  
Prathamesh Ghavanalkar ◽  
Mezia Fernandes ◽  
...  
Keyword(s):  
South Asia ◽  
Plasmodium Vivax ◽  
Anopheles Stephensi ◽  
Parasite Development ◽  
Future Research ◽  
High Quality ◽  
Gametocyte Density ◽  
Feeding Experiments ◽  
South West ◽  
Membrane Feeding

Abstract Background Efforts to study the biology of Plasmodium vivax liver stages, particularly the latent hypnozoites, have been hampered by the limited availability of P. vivax sporozoites. Anopheles stephensi is a major urban malaria vector in Goa and elsewhere in South Asia. Using P. vivax patient blood samples, a series of standard membrane-feeding experiments were performed with An. stephensi under the US NIH International Center of Excellence for Malaria Research (ICEMR) for Malaria Evolution in South Asia (MESA). The goal was to understand the dynamics of parasite development in mosquitoes as well as the production of P. vivax sporozoites. To obtain a robust supply of P. vivax sporozoites, mosquito-rearing and mosquito membrane-feeding techniques were optimized, which are described here. Methods Membrane-feeding experiments were conducted using both wild and laboratory-colonized An. stephensi mosquitoes and patient-derived P. vivax collected at the Goa Medical College and Hospital. Parasite development to midgut oocysts and salivary gland sporozoites was assessed on days 7 and 14 post-feeding, respectively. The optimal conditions for mosquito rearing and feeding were evaluated to produce high-quality mosquitoes and to yield a high sporozoite rate, respectively. Results Laboratory-colonized mosquitoes could be starved for a shorter time before successful blood feeding compared with wild-caught mosquitoes. Optimizing the mosquito-rearing methods significantly increased mosquito survival. For mosquito feeding, replacing patient plasma with naïve serum increased sporozoite production > two-fold. With these changes, the sporozoite infection rate was high (> 85%) and resulted in an average of ~ 22,000 sporozoites per mosquito. Some mosquitoes reached up to 73,000 sporozoites. Sporozoite production could not be predicted from gametocyte density but could be predicted by measuring oocyst infection and oocyst load. Conclusions Optimized conditions for the production of high-quality P. vivax sporozoite-infected An. stephensi were established at a field site in South West India. This report describes techniques for producing a ready resource of P. vivax sporozoites. The improved protocols can help in future research on the biology of P. vivax liver stages, including hypnozoites, in India, as well as the development of anti-relapse interventions for vivax malaria.

scholarly journals The effect of beta-blockers on hemodynamic parameters in patient-specific blood flow simulations of type-B aortic dissection: a virtual study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohammad Amin Abazari ◽  
Deniz Rafieianzab ◽  
M. Soltani ◽  
Mona Alimohammadi
Keyword(s):  
Aortic Dissection ◽  
Clinical Decision Making ◽  
Beta Blockers ◽  
False Lumen ◽  
Specific Treatment ◽  
Left Ventricular ◽  
Patient Specific ◽  
Type B ◽  
Windkessel Model ◽  
Computed Tomography Images

AbstractAortic dissection (AD) is one of the fatal and complex conditions. Since there is a lack of a specific treatment guideline for type-B AD, a better understanding of patient-specific hemodynamics and therapy outcomes can potentially control the progression of the disease and aid in the clinical decision-making process. In this work, a patient-specific geometry of type-B AD is reconstructed from computed tomography images, and a numerical simulation using personalised computational fluid dynamics (CFD) with three-element Windkessel model boundary condition at each outlet is implemented. According to the physiological response of beta-blockers to the reduction of left ventricular contractions, three case studies with different heart rates are created. Several hemodynamic features, including time-averaged wall shear stress (TAWSS), highly oscillatory, low magnitude shear (HOLMES), and flow pattern are investigated and compared between each case. Results show that decreasing TAWSS, which is caused by the reduction of the velocity gradient, prevents vessel wall at entry tear from rupture. Additionally, with the increase in HOLMES value at distal false lumen, calcification and plaque formation in the moderate and regular-heart rate cases are successfully controlled. This work demonstrates how CFD methods with non-invasive hemodynamic metrics can be developed to predict the hemodynamic changes before medication or other invasive operations. These consequences can be a powerful framework for clinicians and surgical communities to improve their diagnostic and pre-procedural planning.

scholarly journals Accuracy comparison of various quantitative [99mTc]Tc-DPD SPECT/CT reconstruction techniques in patients with symptomatic hip and knee joint prostheses

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Martin Braun ◽  
Michal Cachovan ◽  
Felix Kaul ◽  
Federico Caobelli ◽  
Markus Bäumer ◽  
...  
Keyword(s):  
Clinical Outcome ◽  
Quantitative Data ◽  
Diagnostic Tools ◽  
Ct Reconstruction ◽  
Knee Prostheses ◽  
Uptake Quantification ◽  
Ct Data ◽  
Joint Prostheses ◽  
Painful Hip ◽  
Xspect Bone

Abstract Background There is a need for better diagnostic tools that identify loose total hip and knee arthroplasties. Here, we present the accuracy of different 99mTc-dicarboxypropandiphosphate ([99mTc]Tc-DPD) SPECT/CT quantification tools for the detection of loose prostheses in patients with painful hip and knee arthroplasties. Methods Quantitative reconstruction of mineral phase SPECT data was performed using Siemens xSPECT-Quant and xSPECT-Bone, with and without metal artefact reduction (iMAR) of CT-data. Quantitative data (SUVmax values) were compared to intraoperative diagnosis or clinical outcome after at least 1 year as standard of comparison. Cut-off values and accuracies were calculated using receiver operator characteristics. Accuracy of uptake quantification was compared to the accuracy of visual SPECT/CT readings, blinded for the quantitative data and clinical outcome. Results In this prospective study, 30 consecutive patients with 33 symptomatic hip and knee prostheses underwent [99mTc]Tc-DPD SPECT/CT. Ten arthroplasties were diagnosed loose and 23 stable. Mean-SUVmax was significantly higher around loose prostheses compared to stable prostheses, regardless of the quantification method (P = 0.0025–0.0001). Quantification with xSPECT-Bone-iMAR showed the highest accuracy (93.9% [95% CI 79.6–100%]) which was significantly higher compared to xSPECT-Quant-iMAR (81.8% [67.5–96.1%], P = 0.04) and xSPECT-Quant without iMAR (77.4% [62.4–92.4%], P = 0.02). Accuracies of clinical reading were non-significantly lower compared to quantitative measures (84.8% [70.6–99.1%] (senior) and 81.5% [67.5–96.1%] (trainee)). Conclusion Quantification with [99mTc]Tc-DPD xSPECT-Bone-iMAR discriminates best between loose and stable prostheses of all evaluated methods. The overall high accuracy of different quantitative measures underlines the potential of [99mTc]Tc-DPD-quantification as a biomarker and demands further prospective evaluation in a larger number of prosthesis.

scholarly journals Evaluating a calcium-aware kernel for CT CAC scoring with varying surrounding materials and heart rates: a dynamic phantom study

2021 ◽  
Author(s):  
Niels R. van der Werf ◽  
Ronald Booij ◽  
Bernhard Schmidt ◽  
Thomas G. Flohr ◽  
Tim Leiner ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Soft Tissue ◽  
Patient Specific ◽  
Reconstruction Technique ◽  
Ct Reconstruction ◽  
Raw Data ◽  
Heart Rates ◽  
Tissue Equivalent ◽  
Tin Filtration ◽  
Reconstruction Kernel

Abstract Objectives The purpose of this study was twofold. First, the influence of a novel calcium-aware (Ca-aware) computed tomography (CT) reconstruction technique on coronary artery calcium (CAC) scores surrounded by a variety of tissues was assessed. Second, the performance of the Ca-aware reconstruction technique on moving CAC was evaluated with a dynamic phantom. Methods An artificial coronary artery, containing two CAC of equal size and different densities (196 ± 3, 380 ± 2 mg hydroxyapatite cm−3), was moved in the center compartment of an anthropomorphic thorax phantom at different heart rates. The center compartment was filled with mixtures, which resembled fat, water, and soft tissue equivalent CT numbers. Raw data was acquired with a routine clinical CAC protocol, at 120 peak kilovolt (kVp). Subsequently, reduced tube voltage (100 kVp) and tin-filtration (150Sn kVp) acquisitions were performed. Raw data was reconstructed with a standard and a novel Ca-aware reconstruction technique. Agatston scores of all reconstructions were compared with the reference (120 kVp) and standard reconstruction technique, with relevant deviations defined as > 10%. Results For all heart rates, Agatston scores for CAC submerged in fat were comparable to the reference, for the reduced-kVp acquisition with Ca-aware reconstruction kernel. For water and soft tissue, medium-density Agatston scores were again comparable to the reference for all heart rates. Low-density Agatston scores showed relevant deviations, up to 15% and 23% for water and soft tissue, respectively. Conclusion CT CAC scoring with varying surrounding materials and heart rates is feasible at patient-specific tube voltages with the novel Ca-aware reconstruction technique. Key Points • A dedicated calcium-aware reconstruction kernel results in similar Agatston scores for CAC surrounded by fatty materials regardless of CAC density and heart rate. • Application of a dedicated calcium-aware reconstruction kernel allows for radiation dose reduction. • Mass scores determined with CT underestimated physical mass.

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