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166 results on '"Greenwald, Stephen E."'

6. Doppler Radar Sensor-Based Fall Detection Using a Convolutional Bidirectional Long Short-Term Memory Model.

Author

Li, Zhikun, Du, Jiajun, Zhu, Baofeng, Greenwald, Stephen E., Xu, Lisheng, Yao, Yudong, and Bao, Nan

Subjects
CONVOLUTIONAL neural networks, DOPPLER radar, DEEP learning, FREQUENCY spectra, QUALITY of life
Abstract

Falls among the elderly are a common and serious health risk that can lead to physical injuries and other complications. To promptly detect and respond to fall events, radar-based fall detection systems have gained widespread attention. In this paper, a deep learning model is proposed based on the frequency spectrum of radar signals, called the convolutional bidirectional long short-term memory (CB-LSTM) model. The introduction of the CB-LSTM model enables the fall detection system to capture both temporal sequential and spatial features simultaneously, thereby enhancing the accuracy and reliability of the detection. Extensive comparison experiments demonstrate that our model achieves an accuracy of 98.83% in detecting falls, surpassing other relevant methods currently available. In summary, this study provides effective technical support using the frequency spectrum and deep learning methods to monitor falls among the elderly through the design and experimental validation of a radar-based fall detection system, which has great potential for improving quality of life for the elderly and providing timely rescue measures. [ABSTRACT FROM AUTHOR]

Published
2024
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7. COACT: Coronary artery centerline tracker.

Author

Li, Xiaogang, Ji, Lianchang, Zhang, Rongrong, You, Hongrui, Xu, Lisheng, Greenwald, Stephen E., Sun, Yu, Zhang, Libo, and Yang, Benqiang

Subjects
TRACKING algorithms, GRAPH neural networks, AUTOMATIC tracking, IMAGE analysis, CORONARY angiography
Abstract

Background: The curved planar reformation (CPR) technique is one of the most commonly used methods in clinical practice to locate coronary arteries in medical images. Purpose: The artery centerline is the cornerstone for the generation of the CPR image. Here, we describe the development of a new fully automatic artery centerline tracker with the aim of increasing the efficiency and accuracy of the process. Methods: We propose a COronary artery Centerline Tracker (COACT) framework which consists of an ostium point finder (OPFinder) model, an intersection point detector (IPDetector) model and a set of centerline tracking strategies. The output of OPFinder is the ostium points. The function of the IPDetector is to predict the intersections of a sample sphere and the centerlines. The centerline tracking process starts from two ostium points detected by the OPFinder, and combines the results of the IPDetector with a series of strategies to gradually reconstruct the coronary artery centerline tree. Results: Two coronary CT angiography (CCTA) datasets were used to validate the models. Dataset1 contains 160 cases (32 for test and 128 for training) and dataset2 contains 70 cases (20 for test and 50 for training). The results show that the average distance between the ostium points predicted by the OPFinder and the manually annotated ostium points was 0.88 mm, which is similar to the differences between the results obtained by two observers (0.85 mm). For the IPDetector, the average overlap of the predicted and ground truth intersection points was 97.82% and this is also close to the inter‐observer agreement of 98.50%. For the entire coronary centerline tree, the overlap between the results obtained by COACT and the gold standard was 94.33%, which is slightly lower than the inter‐observer agreement, 98.39%. Conclusions: We have developed a fully automatic centerline tracking method for CCTA scans and achieved a satisfactory result. The proposed algorithms are also incorporated in the medical image analysis platform TIMESlice (https://slice‐doc.netlify.app) for further studies. [ABSTRACT FROM AUTHOR]

Published
2024
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8. COACT: Coronary artery centerline tracker

Author

Li, Xiaogang, primary, Ji, Lianchang, additional, Zhang, Rongrong, additional, You, Hongrui, additional, Xu, Lisheng, additional, Greenwald, Stephen E., additional, Sun, Yu, additional, Zhang, Libo, additional, and Yang, Benqiang, additional

Published
2023
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13. Automatic coronary artery segmentation of CCTA images using UNet with a local contextual transformer.

Author

Qianjin Wang, Lisheng Xu, Lu Wang, Xiaofan Yang, Yu Sun, Benqiang Yang, and Greenwald, Stephen E.

Subjects
CORONARY arteries, HEART disease diagnosis, CORONARY circulation, CONVOLUTIONAL neural networks, IMAGE segmentation
Abstract

Coronary artery segmentation is an essential procedure in the computer-aided diagnosis of coronary artery disease. It aims to identify and segment the regions of interest in the coronary circulation for further processing and diagnosis. Currently, automatic segmentation of coronary arteries is often unreliable because of their small size and poor distribution of contrast medium, as well as the problems that lead to over-segmentation or omission. To improve the performance of convolutional-neural-network (CNN) based coronary artery segmentation, we propose a novel automatic method, DR-LCT-UNet, with two innovative components: the Dense Residual (DR) module and the Local Contextual Transformer (LCT) module. The DR module aims to preserve unobtrusive features through dense residual connections, while the LCT module is an improved Transformer that focuses on local contextual information, so that coronary artery-related information can be better exploited. The LCT and DR modules are effectively integrated into the skip connections and encoderdecoder of the 3D segmentation network, respectively. Experiments on our CorArtTS2020 dataset show that the dice similarity coefficient (DSC), Recall, and Precision of the proposed method reached 85.8%, 86.3% and 85.8%, respectively, outperforming 3D-UNet (taken as the reference among the 6 other chosen comparison methods), by 2.1%, 1.9%, and 2.1%. [ABSTRACT FROM AUTHOR]

Published
2023
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15. Reversal and Remission of T2DM – An Update for Practitioners

Author

Shibib,Lina, Al-Qaisi,Mo, Ahmed,Ahmed, Miras,Alexander D, Nott,David, Pelling,Marc, Greenwald,Stephen E, and Guess,Nicola

Subjects
Vascular Health and Risk Management
Abstract

Lina Shibib,1 Mo Al-Qaisi,1 Ahmed Ahmed,1 Alexander D Miras,2 David Nott,1 Marc Pelling,1 Stephen E Greenwald,3 Nicola Guess4 1Department of Surgery and Cancer, Imperial College London, London, UK; 2Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK; 3Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary, University of London, London, UK; 4School of Life Sciences, Westminster University, London, UKCorrespondence: Mo Al-Qaisi, Imperial Weight Centre, Imperial College Healthcare NHS Trust, Praed Street, London, W2 1NY, UK, Tel +44 7968 016315, Email mrcgp74@yahoo.co.ukAbstract: Over the past 50 years, many countries around the world have faced an unchecked pandemic of obesity and type 2 diabetes (T2DM). As best practice treatment of T2DM has done very little to check its growth, the pandemic of diabesity now threatens to make health-care systems economically more difficult for governments and individuals to manage within their budgets. The conventional view has been that T2DM is irreversible and progressive. However, in 2016, the World Health Organization (WHO) global report on diabetes added for the first time a section on diabetes reversal and acknowledged that it could be achieved through a number of therapeutic approaches. Many studies indicate that diabetes reversal, and possibly even long-term remission, is achievable, belying the conventional view. However, T2DM reversal is not yet a standardized area of practice and some questions remain about long-term outcomes. Diabetes reversal through diet is not articulated or discussed as a first-line target (or even goal) of treatment by any internationally recognized guidelines, which are mostly silent on the topic beyond encouraging lifestyle interventions in general. This review paper examines all the sustainable, practical, and scalable approaches to T2DM reversal, highlighting the evidence base, and serves as an interim update for practitioners looking to fill the practical knowledge gap on this topic in conventional diabetes guidelines.Keywords: weight loss, very low energy, very low calorie, bariatric surgery, orlistat, electrical muscle stimulation, low carbohydrate, behaviour change, diabetes reversal, diabetes remission

Published
2022

21. Relationship Between Epicardial Fat volume on Cardiac CT and Atherosclerosis Severity in Three-Vessel Coronary Artery Disease: A Single-Center Cross-Sectional Study

Author

Sun, Yu, primary, Li, Xiao-gang, additional, Xu, Kai, additional, Hou, Jie, additional, You, Hong-rui, additional, Zhang, Rong-rong, additional, Qi, Miao, additional, Zhang, Li-bo, additional, Xu, Li-sheng, additional, Greenwald, Stephen E., additional, and Yang, Ben-Qiang, additional

Published
2021
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32. Role of fetal nutrient restriction and postnatal catch-up growth on structural and mechanical alterations of rat aorta

Author

Gutiérrez-Arzapalo, Perla Y., Rodríguez-Rodríguez, Pilar, Ramiro-Cortijo, David, López de Pablo, Ángel L., López-Giménez, María Rosario, Condezo-Hoyos, Luis, Greenwald, Stephen E., González, Maria del Carmen, Arribas, Silvia M., UAM. Departamento de Fisiología, and UAM. Departamento de Medicina Preventiva y Salud Pública y Microbiología

Subjects
Vascular mechanics, Nutrients, Biología y Biomedicina / Biología, Research Papers, Rats, Elastin, Sexual dimorphism, Fetus, IUGR, Fetal programming, Hypertension, Animals, Collagen, Aorta
Abstract

This is the pre-peer reviewed version of the following article: Role of fetal nutrient restriction and postnatal catch‐up growth on structural and mechanical alterations of rat aorta, which has been published in final form at https://doi.org/10.1113/JP275030. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving, Intrauterine growth restriction (IUGR), induced by maternal undernutrition, leads to impaired aortic development. This is followed by hypertrophic remodelling associated with accelerated growth during lactation. Fetal nutrient restriction is associated with increased aortic compliance at birth and at weaning, but not in adult animals. This mechanical alteration may be related to a decreased perinatal collagen deposition. Aortic elastin scaffolds purified from young male and female IUGR animals also exhibit increased compliance, only maintained in adult IUGR females. These mechanical alterations may be related to differences in elastin deposition and remodelling. Fetal undernutrition induces similar aortic structural and mechanical alterations in young male and female rats. Our data argue against an early mechanical cause for the sex differences in hypertension development induced by maternal undernutrition. However, the larger compliance of elastin in adult IUGR females may contribute to the maintenance of a normal blood pressure level. Fetal undernutrition programmes hypertension development, males being more susceptible. Deficient fetal elastogenesis and vascular growth is a possible mechanism. We investigated the role of aortic mechanical alterations in a rat model of hypertension programming, evaluating changes at birth, weaning and adulthood. Dams were fed ad libitum (Control) or 50% of control intake during the second half of gestation (maternal undernutrition, MUN). Offspring aged 3 days, 21 days and 6 months were studied. Blood pressure was evaluated in vivo. In the thoracic aorta we assessed gross structure, mechanical properties (intact and purified elastin), collagen and elastin content and internal elastic lamina (IEL) organization. Only adult MUN males developed hypertension (systolic blood pressure: MUN males = 176.6 ± 5.6 mmHg; Control males = 136.1 ± 4.9 mmHg). At birth MUN rats were lighter, with smaller aortic cross-sectional area (MUN males = (1.51 ± 0.08) × 10 5 μm 2 , Control males = (2.8 ± 0.04) × 10 5 μm 2 ); during lactation MUN males and females exhibited catch-up growth and aortic hypertrophy (MUN males = (14.5 ± 0.5) × 10 5 μm 2 , Control males = (10.4 ± 0.9) × 10 5 μm 2 ), maintained until adulthood. MUN aortas were more compliant until weaning (functional stiffness: MUN males = 1.0 ± 0.04; Control males = 1.3 ± 0.03), containing less collagen with larger IEL fenestrae, returning to normal in adulthood. Purified elastin from young MUN offspring was more compliant in both sexes; only MUN adult females maintained larger elastin compliance (slope: MUN females = 24.1 ± 1.9; Control females = 33.3 ± 2.8). Fetal undernutrition induces deficient aortic development followed by hypertrophic remodelling and larger aortic compliance in the perinatal period, with similar alterations in collagen and elastin in both sexes. The observed alterations argue against an initial mechanical cause for sex differences in hypertension development. However, the maintenance of high elastin compliance in adult females might protect them against blood pressure rise, This work was supported by the Ministerio de Econom ́ıa yCompetitividad-Spain (Grant number FEM2015-63631-R)

Published
2018

36. Role of fetal nutrient restriction and postnatal catch‐up growth on structural and mechanical alterations of rat aorta

Author

Gutiérrez‐Arzapalo, Perla Y., primary, Rodríguez‐Rodríguez, Pilar, additional, Ramiro‐Cortijo, David, additional, López de Pablo, Ángel L., additional, López‐Giménez, María Rosario, additional, Condezo‐Hoyos, Luis, additional, Greenwald, Stephen E., additional, González, Maria del Carmen, additional, and Arribas, Silvia M., additional

Published
2018
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43. Association of arterial stiffness with single nucleotide polymorphism rs1333049 and metabolic risk factors

Author

Phababpha, Suphawadee, primary, Kukongviriyapan, Upa, additional, Pakdeechote, Poungrat, additional, Senggunprai, Laddawan, additional, Kukongviriyapan, Veerapol, additional, Settasatian, Chatri, additional, Tatsanavivat, Pyatat, additional, Intharaphet, Phongsak, additional, Senthong, Vichai, additional, Komanasin, Nantarat, additional, Settasatian, Nongnuch, additional, and Greenwald, Stephen E, additional

Published
2013
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48. Twin-Twin Transfusion Syndrome

Author

Gardiner, Helena M., primary, Taylor, Myles J.O., additional, Karatza, Ageliki, additional, Vanderheyden, Tina, additional, Huber, Agnes, additional, Greenwald, Stephen E., additional, Fisk, Nicholas M., additional, and Hecher, Kurt, additional

Published
2003
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