Flow Mapping Research Articles

A case report of patent ductus arteriosus in a Brazilian longhair female kitten

Among the congenital cardiac alterations observed in small pets, the persistence of the right aortic arch has been described as a rare anomaly in cats. The ductus arteriosus corresponds to a normal fetal vascular structure derived from the distal portion of the sixth left aortic arch that connects the pulmonary artery to the dorsal aorta. During fetal life, this structure has the function of transporting oxygenated blood from the maternal placenta to the aorta, bypassing the collapsed lungs of the fetus. At birth, the increase of O2 partial pressure dissolved in arterial blood (PaO2) and the decline in prostaglandin concentration cause the closure of the ductus arteriosus in the first hours of life, giving rise to the ligamentum arteriosus. If this process does not occur, the ductus arteriosus will remain patent. In this case report, a 4-month-old longhair female kitten was treated, and, during auscultation, a heart murmur was found. After performing a Doppler echocardiogram and color flow mapping, the presence of continuous turbulent flow in the pulmonary artery was demonstrated, characteristic of patent ductus arteriosus persistence. The animal was sent for surgery, and in the post-surgical Doppler echocardiogram, correction of patent ductus arteriosus was verified, demonstrating the absence of continuous turbulent flow in the pulmonary artery.

An in-silico comparison of anatomical and substrate based AF ablation using electro and optical flow mapping

Abstract Background The pursuit of improved outcomes for persistent AF may necessitate the utilization of innovative technologies and ablation methods. We hypothesize that combining electrophysiologic phase and optical flow mapping could offer a novel approach to identify ablation sites in persistent AF while minimizing ablation area, thereby enhancing the effectiveness of substrate-based ablation compared to a purely empiric strategy. Objective To compare the efficacy of a novel electro-optic flow-based ablation strategy (EOF) with empiric ablation for persistent AF patients using a virtual cohort of bi-atrial models. Methods An exploratory cohort (n=20) from a CT-derived bi-atrial in silico population was utilized to simulate AF. A pipeline was developed to assess ablation targets based on simulated AF and to automatically connect targets to closest inert boundaries. As part of target assessment, phase singularities (PS) and Horn-Schunck average optical flow maps were computed. An intersection of information assessed through PS and curl of average optical flow was utilized to generate EOF maps. 5 x strategies comprising purely anatomical, PS based and EOF guided ablations were simulated (1. PVI; 2. PVI+mitral/roof lines; 3. PVI+mitral/box line; 4. PS+anatomical; 5. EOF+anatomical). Ablation efficacy was determined by first examining change of rhythm via ablation and second by calculating the amount of tissue area ablated. Results Ablating PVI alone (Method 1) did not result in AF termination in any case. Ablating PVI with mitral or roof lines (Method 2) resulted in moderate outcomes (6 AF term. / 3 conv. to AT) whereas ablating PVI with mitral and box lines (Method 3) resulted in improved outcomes (9 AF term. / 4 conv. to AT). Compared to purely anatomical approaches, ablating PS or EOF targets and combining them with roof, mitral lines (Method 4 and Method 5 respectively) saw marked improvement (16 AF term. / 2 conv. to AT). Mapping based on EOF (Method 5) resulted in smaller ablation targets compared to a PS guided strategy (Method 4) with the same outcome. Conclusion AF termination to ablated tissue area ratio was higher for EOF based ablation targets compared to PS based or empiric ablations. Algorithmic generation of ablation lesion masks based on predicted targets can provide novel insights into ablation outcomes. Combining EOF targets with empiric lesions represents a potential ablation strategy of individualized substrate modification for persistent AF.Study Pipeline

Second order conservative Lagrangian DG schemes for compressible flow and their application in preserving spherical symmetry in two-dimensional cylindrical geometry

In this paper, we construct a class of second-order cell-centered Lagrangian discontinuous Galerkin (DG) schemes for the two-dimensional compressible Euler equations on quadrilateral meshes. This Lagrangian DG scheme is based on the physical coordinates rather than the fixed reference coordinates, hence it does not require studying the evolution of the Jacobian matrix for the flow mapping between the different coordinates. The conserved variables are solved directly, and the scheme can preserve the conservation property for mass, momentum and total energy. The strong stability preserving (SSP) Runge-Kutta (RK) method is used for the time discretization. Furthermore, there are two main contributions. Firstly, differently from the previous work, we design a new Lagrangian DG scheme which is truly second-order accurate for all the variables such as density, momentum, total energy, pressure and velocity, while the similar DG schemes in the literature may lose second-order accuracy for certain variables, as shown in numerical experiments. Secondly, as an extension and application, we develop a particular Lagrangian DG scheme in the cylindrical geometry, which is designed to be able to preserve one-dimensional spherical symmetry for all the linear polynomials in two-dimensional cylindrical coordinates when computed on an equal-angle-zoned initial grid. The distinguished feature is that it can maintain both the spherical symmetry and conservation properties, which is very important for many applications such as implosion problems. A series of numerical experiments in the two-dimensional Cartesian and cylindrical coordinates are given to demonstrate the good performance of the Lagrangian DG schemes in terms of accuracy, symmetry and non-oscillation.

A heterogeneous ultrasound open scanner for the real-time implementation of computationally demanding imaging methods.

Ultrasound open scanners have recently boosted the development and validation of novel imaging techniques. They are usually split into hardware- or software-oriented systems, depending on whether they process the echo data using embedded FPGAs/DSPs or a GPU on a host PC. The goal of this work was to realize a high-performance heterogeneous open scanner capable of leveraging the strengths of both hardware and software-oriented systems. The elaboration power of the 256-channel ultrasound advanced open platform (ULA-OP 256) was further enhanced by embedding a compact co-processing GPU system-on-module (SoM). By carefully avoiding latencies and overheads through low-level optimization work, an efficient PCIe communication interface was established between the GPU and the processing devices onboard the ULA-OP 256. As a proof of concept of the enhanced system, the high frame rate color flow mapping technique was implemented on the GPU SoM and tested. Compared to a previous DSP-based implementation, higher real-time frame rates were achieved together with unprecedented flexibility in setting crucial parameters such as the ensemble length (EL). For example, by setting EL=64 and a continuous-time high-pass filter, the flow was investigated with high temporal and spatial resolution in the femoral vein bifurcation (frame rate = 1.1 kHz) and carotid artery bulb (4.3 kHz), highlighting the flow disturbances due to valve aperture and secondary velocity components, respectively. The results of this work promote the development of other computational-expensive processing algorithms in real-time and may inspire the next generation of ultrasound high-performance heterogeneous scanners.

PVI-Only is Not Enough for All Persistent AF Patients: A FLOW-AF Subgroup Analysis

BackgroundSince the STAR-AF II trial, there has been a trend toward pulmonary vein isolation (PVI)-only ablation strategies for persistent atrial fibrillation (PeAF). Electrographic Flow (EGF) mapping can identify active sources of AF and estimate the electrographic flow consistency (EGFC) of wavefront propagation through substrate, revealing functional AF mechanisms. ObjectiveExamine the success of a PVI-only ablation strategy for a redo PeAF/long-standing PeAF population. MethodsFLOW-AF (NCT04473963) prospectively enrolled non-paroxysmal AF patients undergoing redo ablation at 4 centers. One-minute EGF recordings using 64-pole basket catheters were obtained both pre-PVI and post-PVI following a 20-minute wait and confirmation of electrical isolation of veins. Patients with EGF-identified sources were randomized 1:1 to EGF-guided source ablation v. PVI-only. Patients with no sources were not randomized and mostly received PVI-only. ResultsStudy of 85 patients enrolled: 24 with EGF-identified sources randomized to PVI-only and 23 with no sources receiving PVI-only. Of these 47 patients, those with sources (Group 2) had different clinical characteristics including older age and higher CHA2DS2-VASc compared with those with sources (Group 1). After PVI-only, Group 1 had 70% (16/23) freedom from recurrent AF (FFAF) within one year v. Group 2 with 35% (8/23), p=0.018. Additionally, patients with high electrographic flow consistency (EGFC) indicative of healthy or normal substrate had 67% (10/15) FFAF v. 45% (14/31) in those with low EGFC suggestive of abnormal substrate, p=0.011. ConclusionSuccess rate in no sources patients receiving PVI-only is better than in those with sources randomized to PVI-only. For the clinically heterogenous population of PeAF patients, the presence of EGF-identified sources matters clinically, and PVI-only will not be enough for all patients.

Blowup dynamics for smooth equivariant solutions to energy critical Landau-Lifschitz flow

In this paper, we study the energy critical 1-equivariant Landau-Lifschitz flow mapping R2 to S2 with arbitrary given coefficients ρ1∈R,ρ2>0. We prove that there exists a codimension one smooth well-localized set of initial data arbitrarily close to the ground state which generates type-II finite-time blowup solutions, and give a precise description of the corresponding singularity formation. In our proof, both the Schrödinger part and the heat part play important roles in the construction of approximate solutions and the mixed energy/Morawetz functional. However, the blowup rate is independent of the coefficients.

Correction: Elementary flow mapping across life cycle inventory data systems: A case study for data interoperability under the global life cycle assessment data access (GLAD) initiative

Correction: Elementary flow mapping across life cycle inventory data systems: A case study for data interoperability under the global life cycle assessment data access (GLAD) initiative

Enhancing environmental sustainability in a Circular Waste Bioeconomy: A hierarchical framework driven by operational efficiency and agro-energy management

The increasing generation of agro-waste poses environmental and economic challenges. Traditional farming practices often neglect the potential for agro-waste valorization, leading to inefficient disposal and resource wastage. This study addresses the lack of hierarchical models to guide the implementation of Circular Waste Bioeconomy (CWBE) by developing such a model and identifying key driving aspects and practical criteria. A mixed method combining the fuzzy Delphi method and fuzzy decision-making trial and evaluation laboratory is adopted for attribute validity and the analysis of cause-and-effect interrelationships. The results reveal that operational efficiency and agro-energy management are crucial drivers for enhancing environmental sustainability, cascading use, and developing bio-based markets. Key criteria for CWBE implementation in Colombia include life cycle assessment, biomass technology adoption, waste flow mapping, incentivizing stewardship behavior, bioenergy adoption, and value optimization. This study contributes to the CWBE literature by providing a hierarchical framework and actionable insights to guide policymakers and practitioners in promoting sustainable agro-waste management.

Intracardiac energy inefficiency during decompensated and compensated heart failure.

The mechanisms underlying the acute decompensation of heart failure (HF) remain unclear. The present study examined intracardiac dynamics during decompensated HF using echo-vector flow mapping. Fifty patients admitted for decompensated HF were prospectively enrolled, and intracardiac energy loss (EL) was assessed by echo-vector flow mapping at admission (decompensated HF) and discharge (compensated HF). Outcome measures were average EL in the left ventricle (LV) in decompensated and compensated HF and were compared with those in 40 stable non-HF patients with cardiovascular diseases. The mean age of HF patients was 80.8±12.4years. The prevalence of both females and atrial fibrillation was 48.0%. The prevalence of HF with a reduced ejection fraction (<40%) (HFrEF) was 34.0%. The prevalence of decompensated HF classified into clinical scenario 1 was 33.3%. Blood pressure and NT-proBNP were significantly higher in decompensated HF than in compensated HF, while the ejection fraction (EF) was significantly lower. Average EL was significantly higher in compensated HF patients than in non-HF patients (40mW/m·L vs. 26mW/m·L, P=0.047). A multivariable analysis identified age, systolic blood pressure, LVEF, and the absence of chronic obstructive pulmonary disease as independent risk factors for high LV-EL regardless of the presence of HF. Furthermore, average EL in HF patients was significantly higher under acute decompensated conditions than under compensated conditions (55mE/m·L vs. 40mE/m·L, [+18mE/m·L, P=0.03]). Higher EL under decompensated HF conditions was significant in non-HFrEF (+19mW/m·L, P=0.009) and clinical scenario 1 (+23mW/m·L, P=0.008). The multivariable analysis identified eGFR as an independent risk factor for a decrease in average LV-EL under decompensated conditions. Energy inefficiency in LV was apparent even in stable HF patients and significant under acute decompensated conditions, particularly in HF with preserved EF and clinical scenario 1.

Electrographic flow mapping of atrial fibrillation.

A low ceiling of efficacy exists for the treatment of persistent atrial fibrillation via pulmonary vein isolation without adjunctive ablations, which is likely because they do not target an individual patient's specific underlying disease mechanisms. Electrographic flow (EGF) mapping is the first system that reliably displays wavefront propagation through the atria. It is a promising tool for localizing sources of atrial fibrillation, guiding targeted ablation, and visualizing conduction through the atrial substrate. We describe EGF mapping with emphasis on contemporary studies examining map reproducibility and use cases in the preclinical and clinical environment. Animal experiments demonstrated that maps were interpretable across increasingly complex rhythms with pacing during spontaneously persistent atrial fibrillation reliably simulating EGF sources. The FLOW-AF randomized controlled trial showed that source ablation improved outcomes and that EGF map properties may be used to phenotype patients based on their atrial fibrillation mechanisms and recurrence likelihoods. Targeted ablation strategies balance the risks of insufficiently ablating atrial fibrillation triggers with exacerbating disease through additional scar formation. EGF mapping leverages spatiotemporal relationships in voltage to localize sources and quantify substrate health. Further research is needed to optimize phenotyping and treatment efforts.

Hydrodynamic characteristics of detachment length and flow mapping in T-junction circular microchannel

This study investigates the droplet formation process in T-junction circular microchannels, emphasizing the influence of wetting properties and contact angles under various operating conditions. A coupled Volume-of-Fluid (VOF)/Level-set multiphase model is employed for Computational Fluid Dynamics (CFD) simulations to accurately capture the microscale phenomena. The effects of contact angles ranging from 125° to 145°, two-phase flow velocities (0.04–0.25 m/s), and interfacial tension (0.035–0.055 N/m) are systematically analyzed. The findings reveal that these parameters significantly impact the detachment length and flow patterns, with four distinct flow regimes identified: dripping, slug, jetting, and annular flow. New dimensionless correlations for slug and detachment lengths are developed and validated through experimental data, offering improved predictive capabilities. The comprehensive flow mapping provided in this study enhances the understanding of multiphase flows in microchannels, offering valuable insights for the optimization of microfluidic device design and practical applications such as extractive desulphurization. These contributions present a novel approach to integrating contact angle effects into microfluidic research, addressing previously overlooked aspects and providing robust guidelines for future studies.

Lean Six Sigma quality improvement approach to implement clinical practice guidelines for prescribing opiates for chronic pain in a primary care setting

BackgroundImplementing guidelines for chronic opioid management during a clinic merger posed significant challenges. Our aim was to increase the percentage of chronic pain evaluations and urine toxicology tests in patients...

Label free, capillary-scale blood flow mapping in vivo reveals that low intensity focused ultrasound evokes persistent dilation in cortical microvasculature.

Non-invasive, low intensity focused ultrasound (FUS) is an emerging neuromodulation technique that offers the potential for precision, personalized therapy. An increasing body of research has identified mechanosensitive ion channels that can be modulated by FUS and support acute electrical activity in neurons. However, neuromodulatory effects that persist from hours to days have also been reported. The brain's ability to provide targeted blood flow to electrically active regions involve a multitude of non-neuronal cell types and signaling pathways in the cerebral vasculature; an open question is whether persistent effects can be attributed, at least partly, to vascular mechanisms. Using a novel in vivo optical approach, we found that microvascular responses, unlike larger vessels which prior investigations have explored, exhibit persistent dilation following sonication without the use of microbubbles. This finding and approach offers a heretofore unseen aspect of the effects of FUS in vivo and indicate that concurrent changes in neurovascular function may partially underly persistent neuromodulatory effects.

Age-related wall shear stress changes assessed by vascular vector flow mapping in the carotid arteries of healthy adults: a cross-sectional study.

Wall shear stress (WSS) is related to the pathogenesis of atherosclerosis. WSS is affected by a variety of hemodynamic factors, and there is still a lack of accurate and objective methods for measuring it. This study sought to evaluate hemodynamic changes in WSSmaximum (max), WSSmean, WSSminimum (min) in the common carotid artery of healthy adults of different ages using vascular vector flow mapping (VFM). A retrospective analysis was conducted on 70 healthy volunteers aged 20-89 years who were recruited from our Ultrasound Department between February 2021 and June 2021. An ultrasound system with a 3-15 MHz probe was used to determine regions of interest (ROIs) of the common carotid artery. VFM-based WSS measurements were obtained by selecting ROIs with optimal image quality from three full cardiac cycles. The participants were divided into the following seven age groups: the 20s group, the 30s group, the 40s group, the 50s group, the 60s group, the 70s group, and the 80s group. The WSS parameters were compared among the age groups. An analysis of variance or a Kruskal-Wallis test was used to evaluate the difference among the groups, and a Pearson analysis and linear regression were used for the correlation and trend analysis. The WSS parameters were quantified using vascular VFM software. The WSSmax, WSSmean, WSSmin differed among the age groups and gradually decreased with age, the elderly were significantly lower than the young. The Pearson correlation coefficient of the WSSmax and age was -0.556 (P<0.001), that of the WSSmean and age was -0.461 (P<0.001), and that of the WSSmin and age was -0.308 (P<0.001). The WSS parameters with age are negatively correlated the carotid intima-media thickness differed between the groups. The carotid WSSmax, WSSmean, WSSmin can be quantitatively and visually analyzed using the vascular VFM technique. In healthy adults of different ages, the carotid WSSmax, WSSmean, WSSmin decreased with age. Our findings about the normal values of carotid WSS maybe have clinical reference value for future studies.

Landscape genetics of spruce grouse at the trailing edge of the boreal forest

Populations on the periphery of a species range generally occupy marginal or less continuous habitat and can have greater extinction risk than populations in the range‐center. For climate‐sensitive populations on the trailing edge of a species' distribution (i.e. low latitude or low elevation), the effects of climate change are expected to compound these threats, increasing the vulnerability of these populations. The spruce grouse Canachites canadensis is a boreal forest specialist that is expected to experience range contraction at the trailing edge of its range due to climate change. In this study, we investigated the genetic structure, genetic diversity, and connectivity of spruce grouse in Minnesota, along the southeastern range limit in the United States. Clustering algorithms and genetic diversity indices suggested a single continuous population occurred throughout northern Minnesota. We detected no signatures of recent inbreeding or population bottlenecks. We used maximum likelihood population effects modeling and identified coniferous forest land cover and lower average spring temperatures as predictors of gene flow. We used two approaches based on circuit theory to map the potential for gene flow and identified regions of consistently high gene flow in the northwest and northeast of the study area. Omniscape, which incorporated additional parameters representing the likely origins of dispersers and the maximum dispersal distance, suggested a more continuous gene flow landscape than did Circuitscape. Our work highlights the current genetic integrity of one of the largest populations of the eastern subspecies of spruce grouse C. c. canadensis in the United States, identifies key landscape attributes for functional connectivity, and demonstrates complementary approaches of Circuitscape and Omniscape for gene flow mapping.

The incremental value of left ventricular energy loss in predicting adverse events in chronic kidney disease patients with preserved ejection fraction

BackgroundVector flow mapping (VFM) is a new echocardiographic technology that can effectively evaluate systolic and diastolic hemodynamic function. However, little is known about the prognostic value of VFM-related parameters. In this paper we aimed to investigate whether left ventricular energy loss (EL) parameters as assessed by VFM enhance prediction of adverse events in patients with chronic kidney disease with preserved ejection fraction. MethodsOne hundred thirty-nine prospectively recruited patients (66% male, 58% on dialysis) with CKD stage 3–5 with normal left ventricular ejection fraction (LVEF) made up the study cohort. Global longitudinal strain (GLS) was calculated using 2-dimensional speckle tracking, and the LV EL during one cardiac cycle for each period was measured using VFM technology. Participants were followed for 4.17 ± 1.58 years for the primary end point of overall mortality and major adverse cardiovascular events (MACE). ResultsForty-five (32%) patients had a primary endpoint event. The EL during each period especially during the ejection stage (Ej-EL) was significantly higher in patients with adverse events than in those without, meanwhile the LV GLS were lower. The Ej-EL (HR: 1.11; 95% CI: 1.06–1.15) and LV GLS (HR: 0.87; 95% CI: 0.81–0.94) (all P < .001) were independent predictors for the primary end point. Increased Ej-EL (≥6.13, 10−3 J/m s) and impaired GLS (<15.52, %) were associated with a higher risk of overall mortality death and MACE (log rank χ2 = 26.94, 7.19; P < .001, =0.007), and DeLong tests showed that Ej-EL (AUC = 0.823) has a slight advantage in predicting adverse events compared to GLS (AUC = 0.681). Furthermore, the addition of Ej-EL to a model with conventional parameters did more to improve the model's discrimination compared to GLS. ConclusionsIncreased Ej-EL as determined by VFM is associated with a higher risk of overall death and MACE in CKD patients with preserved EF.

Training and Validating a Neural Network for Myocardial Blood Flow Mapping in 82Rb PET: A Multicenter Study

Training and Validating a Neural Network for Myocardial Blood Flow Mapping in 82Rb PET: A Multicenter Study

Methodology for the data flow mapping and analysis in the European Member States

Methodology for the data flow mapping and analysis in the European Member States

4D flow MRI: value and clinical perspectives in patients with pathology of the heart and great vessels (part 2): A review

The study of blood flow is becoming a new trend in cardiology and cardiovascular surgery. Based on the literature and our own data, a review is presented on the use of 4D flow in diseases of the heart and blood vessels. The main state of the question about the features of the application of the technique in various pathologies of the cardiovascular system is described in detail, the priorities, limitations and promising directions of the technique application are considered taking into account the goals of practical medicine. The review consists of two parts. The first is devoted to general issues, limitations of the technique, and issues of 4D flow mapping in patients with lesions of the great vessels. In the second part, the emphasis is on the use of 4D flow MRI in the study of intraventricular blood flow and the application of the technique in congenital heart and vascular diseases.

Activity flow under the manipulation of cognitive load and training

Flexible cognitive functions, such as working memory (WM), usually require a balance between localized and distributed information processing. However, it is challenging to uncover how local and distributed processing specifically contributes to task-induced activity in a region. Although the recently proposed activity flow mapping approach revealed the relative contribution of distributed processing, few studies have explored the adaptive and plastic changes that underlie cognitive manipulation. In this study, we recruited 51 healthy volunteers (31 females) and investigated how the activity flow and brain activation of the frontoparietal systems was modulated by WM load and training. While the activation of both executive control network (ECN) and dorsal attention network (DAN) increased linearly with memory load at baseline, the relative contribution of distributed processing showed a linear response only in the DAN, which was prominently attributed to within-network activity flow. Importantly, adaptive training selectively induced an increase in the relative contribution of distributed processing in the ECN and also a linear response to memory load, which were predominantly due to between-network activity flow. Furthermore, we demonstrated a causal effect of activity flow prediction through training manipulation on connectivity and activity. In contrast with classic brain activation estimation, our findings suggest that the relative contribution of distributed processing revealed by activity flow prediction provides unique insights into neural processing of frontoparietal systems under the manipulation of cognitive load and training. This study offers a new methodological framework for exploring information integration versus segregation underlying cognitive processing.