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1.
J Obstet Gynaecol ; 44(1): 2319791, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38419407

RESUMO

BACKGROUND: Coronavirus (COVID-19) pandemic has affected the training and wellbeing of obstetrics and gynaecology (O&G) trainees. The aim of this review is to offer a worldwide overview on its' impact on the mental health of O&G trainees, so that measures can be put into place to better support trainees during the transition back to the 'new normal'. METHODS: Key search terms used on PubMed and Google Scholar databases include: mental health, COVID-19, O&G, trainees, residents. RESULTS: Fifteen articles (cumulative number of respondents = 3230) were identified, of which eight employed validated questionnaires (n = 1807 respondents), while non-validated questionnaires were used in seven (n = 1423 respondents). Studies showed that COVID-19 appeared to exert more of a negative impact on females and on senior trainees' mental health, while protective factors included marriage/partner and having had children. Validated and non-validated questionnaires suggested that trainees were exposed to high levels of anxiety and depression. Their mental health was also affected by insomnia, stress, burnout and fear of passing on the virus. DISCUSSION: This review analyses the global impact of COVID-19 on O&G trainees' mental health, showing a pervasive negative effect linked to fear of the virus. Limited psychological support has led to prolonged issues, hindering patient safety and increasing sick leave. The study underscores the urgency of comprehensive support, particularly in female-dominated fields. Addressing these challenges is crucial for future pandemics, highlighting the need to learn from past mistakes and prioritise mental health resources for trainee well-being during and beyond pandemics.


This review provides a worldwide overview of the impact Coronavirus (COVID-19) pandemic on the mental health of obstetrics and gynaecology (O&G) trainees. Fifteen articles were identified, of which eight employed validated questionnaires (n = 1807 respondents), while non-validated questionnaires were used in seven (n = 1423 respondents). The pandemic appeared to exert more of a negative impact on females and on senior trainees' mental health, while protective factors included marriage/partner and having had children. Studies suggested that trainees were exposed to high levels of anxiety and depression. Their mental health was also affected by insomnia, stress, burnout and fear of passing on the virus.Limited psychological support has led to prolonged recovery issues and increasing sick leave. The study underscores the urgency of comprehensive support, particularly in female-dominated fields. Addressing these challenges is crucial for future pandemics, highlighting the need to learn from past mistakes and prioritise mental health resources for trainee well-being.


Assuntos
COVID-19 , Ginecologia , Obstetrícia , Gravidez , Criança , Feminino , Humanos , COVID-19/epidemiologia , Pandemias , Saúde Mental , SARS-CoV-2 , Inquéritos e Questionários
2.
J Cyst Fibros ; 2024 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-38233246

RESUMO

INTRODUCTION: The efficacy and safety of elexacaftor/tezacaftor/ivacaftor (ETI) have been established in prospective clinical trials. Liver function test elevations were observed in a greater proportion of patients receiving ETI compared with placebo; however, the relatively small number of patients and short duration of study preclude detection of rare but clinically significant associations with drug-induced liver injury (DILI). To address this gap, we assessed the real-world risk of DILI associated with ETI through data mining of the FDA adverse event reporting system (FAERS). METHODS: Disproportionality analyses were conducted on FAERS data from the fourth quarter of 2019 through the third quarter of 2022. Comparative patient demographics, onset time and outcomes for ETI-DILI were also obtained. RESULTS: 452 reports of DILI associated with ETI were found, representing 2.1 % of all adverse event reports for ETI. All disproportionality measures were significant for ETI-DILI at p < 0.05; the reporting odds ratio (ROR) (2.82) was comparable to that of drugs classified by FDA as "Most-DILI concern". The most notable demographic finding was a male majority (5:4 male to female ratio) for ETI-DILI compared to a female majority (4:5 male to female ratio) for non ETI-DILI. Median ETI-DILI onset time was 50.5 days, and hospitalization was the second most common complication. CONCLUSION: Using FAERS data, ETI was found to be disproportionately associated with DILI. Future research is needed to investigate the hepatotoxic mechanisms and assess potential mitigation strategies for ETI-induced hepatotoxicity.

3.
Artigo em Inglês | MEDLINE | ID: mdl-38031559

RESUMO

Cardiac cine magnetic resonance imaging (MRI) has been used to characterize cardiovascular diseases (CVD), often providing a noninvasive phenotyping tool. While recently flourished deep learning based approaches using cine MRI yield accurate characterization results, the performance is often degraded by small training samples. In addition, many deep learning models are deemed a "black box," for which models remain largely elusive in how models yield a prediction and how reliable they are. To alleviate this, this work proposes a lightweight successive subspace learning (SSL) framework for CVD classification, based on an interpretable feedforward design, in conjunction with a cardiac atlas. Specifically, our hierarchical SSL model is based on (i) neighborhood voxel expansion, (ii) unsupervised subspace approximation, (iii) supervised regression, and (iv) multi-level feature integration. In addition, using two-phase 3D deformation fields, including end-diastolic and end-systolic phases, derived between the atlas and individual subjects as input offers objective means of assessing CVD, even with small training samples. We evaluate our framework on the ACDC2017 database, comprising one healthy group and four disease groups. Compared with 3D CNN-based approaches, our framework achieves superior classification performance with 140× fewer parameters, which supports its potential value in clinical use.

4.
IEEE Trans Image Process ; 32: 5933-5947, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37903048

RESUMO

Dynamic point cloud is a volumetric visual data representing realistic 3D scenes for virtual reality and augmented reality applications. However, its large data volume has been the bottleneck of data processing, transmission, and storage, which requires effective compression. In this paper, we propose a Perceptually Weighted Rate-Distortion Optimization (PWRDO) scheme for Video-based Point Cloud Compression (V-PCC), which aims to minimize the perceptual distortion of reconstructed point cloud at the given bit rate. Firstly, we propose a general framework of perceptually optimized V-PCC to exploit visual redundancies in point clouds. Secondly, a multi-scale Projection based Point Cloud quality Metric (PPCM) is proposed to measure the perceptual quality of 3D point cloud. The PPCM model comprises 3D-to-2D patch projection, multi-scale structural distortion measurement, and fusion model. Approximations and simplifications of the proposed PPCM are also presented for both V-PCC integration and low complexity. Thirdly, based on the simplified PPCM model, we propose a PWRDO scheme with Lagrange multiplier adaptation, which is incorporated into the V-PCC to enhance the coding efficiency. Experimental results show that the proposed PPCM models can be used as standalone quality metrics, and they are able to achieve higher consistency with the human subjective scores than the state-of-the-art objective visual quality metrics. Also, compared with the latest V-PCC reference model, the proposed PWRDO-based V-PCC scheme achieves an average bit rate reduction of 13.52%, 8.16%, 10.56% and 9.54%, respectively, in terms of four objective visual quality metrics for point clouds. It is significantly superior to the state-of-the-art coding algorithms. The computational complexity of the proposed PWRDO increases by 1.71% and 0.05% on average to the V-PCC encoder and decoder, respectively, which is negligible. The source codes of the PPCM and PWRDO schemes are available at https://github.com/VVCodec/PPCM-PWRDO.

5.
IEEE Trans Pattern Anal Mach Intell ; 45(12): 14856-14871, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37647182

RESUMO

An enhanced label propagation (LP) method called GraphHop was proposed recently. It outperforms graph convolutional networks (GCNs) in the semi-supervised node classification task on various networks. Although the performance of GraphHop was explained intuitively with joint node attribute and label signal smoothening, its rigorous mathematical treatment is lacking. In this paper, we propose a label efficient regularization and propagation (LERP) framework for graph node classification, and present an alternate optimization procedure for its solution. Furthermore, we show that GraphHop only offers an approximate solution to this framework and has two drawbacks. First, it includes all nodes in the classifier training without taking the reliability of pseudo-labeled nodes into account in the label update step. Second, it provides a rough approximation to the optimum of a subproblem in the label aggregation step. Based on the LERP framework, we propose a new method, named the LERP method, to solve these two shortcomings. LERP determines reliable pseudo-labels adaptively during the alternate optimization and provides a better approximation to the optimum with computational efficiency. Theoretical convergence of LERP is guaranteed. Extensive experiments are conducted to demonstrate the effectiveness and efficiency of LERP. That is, LERP outperforms all benchmarking methods, including GraphHop, consistently on five common test datasets, two large-scale networks, and an object recognition task at extremely low label rates (i.e., 1, 2, 4, 8, 16, and 20 labeled samples per class).

6.
Public Health ; 221: 131-134, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37451201

RESUMO

OBJECTIVES: Relative deprivation has been linked to various adverse health outcomes. However, the potential mediating factors in the association between relative deprivation and health outcomes remain unclear. This study aimed to (1) examine the association between relative deprivation and self-rated health and health-related quality of life among the working-age population in Taiwan and (2) investigate the mediating effect of subjective social status. STUDY DESIGN: Cross-sectional study using nationally representative data. METHODS: Data were obtained from the 2022 Taiwan Social Change Survey conducted from September 2021 to April 2022. We analyzed 1108 participants aged 25-64 years. Relative deprivation was measured using the Yitzhaki Index based on individual monthly income from all sources. Health-related quality of life was assessed using the 12-item Short Form Health Survey. RESULTS: After adjusting for all covariates and absolute income, least-squares regression models indicated a negative association between the Yitzhaki Index and self-rated health, as well as the physical and mental components of health-related quality of life. Furthermore, subjective social status partially mediates the association between relative income deprivation and poorer self-rated health and health-related quality of life. CONCLUSIONS: The findings support the psychosocial effect of the relative deprivation measure, emphasizing the importance of addressing relative deprivation to improve health-related quality of life among the working-age population.


Assuntos
Qualidade de Vida , Status Social , Humanos , Estudos Transversais , Renda , Inquéritos e Questionários , Nível de Saúde
7.
Commun Biol ; 6(1): 630, 2023 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-37301948

RESUMO

Coral reefs in the Central Indo-Pacific region comprise some of the most diverse and yet threatened marine habitats. While reef monitoring has grown throughout the region in recent years, studies of coral reef benthic cover remain limited in spatial and temporal scales. Here, we analysed 24,365 reef surveys performed over 37 years at 1972 sites throughout East Asia by the Global Coral Reef Monitoring Network using Bayesian approaches. Our results show that overall coral cover at surveyed reefs has not declined as suggested in previous studies and compared to reef regions like the Caribbean. Concurrently, macroalgal cover has not increased, with no indications of phase shifts from coral to macroalgal dominance on reefs. Yet, models incorporating socio-economic and environmental variables reveal negative associations of coral cover with coastal urbanisation and sea surface temperature. The diversity of reef assemblages may have mitigated cover declines thus far, but climate change could threaten reef resilience. We recommend prioritisation of regionally coordinated, locally collaborative long-term studies for better contextualisation of monitoring data and analyses, which are essential for achieving reef conservation goals.


Assuntos
Antozoários , Recifes de Corais , Animais , Teorema de Bayes , Oceanos e Mares
9.
IEEE Trans Neural Netw Learn Syst ; 34(11): 9287-9301, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35302944

RESUMO

A scalable semisupervised node classification method on graph-structured data, called GraphHop, is proposed in this work. The graph contains all nodes' attributes and link connections but labels of only a subset of nodes. Graph convolutional networks (GCNs) have provided superior performance in node label classification over the traditional label propagation (LP) methods for this problem. Nevertheless, current GCN algorithms suffer from a considerable amount of labels for training because of high model complexity or cannot be easily generalized to large-scale graphs due to the expensive cost of loading the entire graph and node embeddings. Besides, nonlinearity makes the optimization process a mystery. To this end, an enhanced LP method, called GraphHop, is proposed to tackle these problems. GraphHop can be viewed as a smoothening LP algorithm, in which each propagation alternates between two steps: label aggregation and label update. In the label aggregation step, multihop neighbor embeddings are aggregated to the center node. In the label update step, new embeddings are learned and predicted for each node based on aggregated results from the previous step. The two-step iteration improves the graph signal smoothening capacity. Furthermore, to encode attributes, links, and labels on graphs effectively under one framework, we adopt a two-stage training process, i.e., the initialization stage and the iteration stage. Thus, the smooth attribute information extracted from the initialization stage is consistently imposed in the propagation process in the iteration stage. Experimental results show that GraphHop outperforms state-of-the-art graph learning methods on a wide range of tasks in graphs of various sizes (e.g., multilabel and multiclass classification on citation networks, social graphs, and commodity consumption graphs).

10.
IEEE Trans Neural Netw Learn Syst ; 34(12): 10711-10723, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35544501

RESUMO

Learning low-dimensional representations of bipartite graphs enables e-commerce applications, such as recommendation, classification, and link prediction. A layerwise-trained bipartite graph neural network (L-BGNN) embedding method, which is unsupervised, efficient, and scalable, is proposed in this work. To aggregate the information across and within two partitions of a bipartite graph, a customized interdomain message passing (IDMP) operation and an intradomain alignment (IDA) operation are adopted by the proposed L-BGNN method. Furthermore, we develop a layerwise training algorithm for L-BGNN to capture the multihop relationship of large bipartite networks and improve training efficiency. We conduct extensive experiments on several datasets and downstream tasks of various scales to demonstrate the effectiveness and efficiency of the L-BGNN method as compared with state-of-the-art methods. Our codes are publicly available at https://github.com/TianXieUSC/L-BGNN.

11.
Artigo em Inglês | MEDLINE | ID: mdl-35983176

RESUMO

Unsupervised domain adaptation (UDA) has been widely used to transfer knowledge from a labeled source domain to an unlabeled target domain to counter the difficulty of labeling in a new domain. The training of conventional solutions usually relies on the existence of both source and target domain data. However, privacy of the large-scale and well-labeled data in the source domain and trained model parameters can become the major concern of cross center/domain collaborations. In this work, to address this, we propose a practical solution to UDA for segmentation with a black-box segmentation model trained in the source domain only, rather than original source data or a white-box source model. Specifically, we resort to a knowledge distillation scheme with exponential mixup decay (EMD) to gradually learn target-specific representations. In addition, unsupervised entropy minimization is further applied to regularization of the target domain confidence. We evaluated our framework on the BraTS 2018 database, achieving performance on par with white-box source model adaptation approaches.

12.
Artigo em Inglês | MEDLINE | ID: mdl-35862331

RESUMO

The multilayer perceptron (MLP) neural network is interpreted from the geometrical viewpoint in this work, that is, an MLP partition an input feature space into multiple nonoverlapping subspaces using a set of hyperplanes, where the great majority of samples in a subspace belongs to one object class. Based on this high-level idea, we propose a three-layer feedforward MLP (FF-MLP) architecture for its implementation. In the first layer, the input feature space is split into multiple subspaces by a set of partitioning hyperplanes and rectified linear unit (ReLU) activation, which is implemented by the classical two-class linear discriminant analysis (LDA). In the second layer, each neuron activates one of the subspaces formed by the partitioning hyperplanes with specially designed weights. In the third layer, all subspaces of the same class are connected to an output node that represents the object class. The proposed design determines all MLP parameters in a feedforward one-pass fashion analytically without backpropagation. Experiments are conducted to compare the performance of the traditional backpropagation-based MLP (BP-MLP) and the new FF-MLP. It is observed that the FF-MLP outperforms the BP-MLP in terms of design time, training time, and classification performance in several benchmarking datasets. Our source code is available at https://colab.research.google.com/drive/1Gz0L8A-nT4ijrUchrhEXXsnaacrFdenn?usp = sharing.

13.
Artigo em Inglês | MEDLINE | ID: mdl-35895653

RESUMO

Unsupervised domain adaptation (UDA) has been successfully applied to transfer knowledge from a labeled source domain to target domains without their labels. Recently introduced transferable prototypical networks (TPNs) further address class-wise conditional alignment. In TPN, while the closeness of class centers between source and target domains is explicitly enforced in a latent space, the underlying fine-grained subtype structure and the cross-domain within-class compactness have not been fully investigated. To counter this, we propose a new approach to adaptively perform a fine-grained subtype-aware alignment to improve the performance in the target domain without the subtype label in both domains. The insight of our approach is that the unlabeled subtypes in a class have the local proximity within a subtype while exhibiting disparate characteristics because of different conditional and label shifts. Specifically, we propose to simultaneously enforce subtype-wise compactness and class-wise separation, by utilizing intermediate pseudo-labels. In addition, we systematically investigate various scenarios with and without prior knowledge of subtype numbers and propose to exploit the underlying subtype structure. Furthermore, a dynamic queue framework is developed to evolve the subtype cluster centroids steadily using an alternative processing scheme. Experimental results, carried out with multiview congenital heart disease data and VisDA and DomainNet, show the effectiveness and validity of our subtype-aware UDA, compared with state-of-the-art UDA methods.

14.
Front Neurosci ; 16: 837646, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35720708

RESUMO

Unsupervised domain adaptation (UDA) is an emerging technique that enables the transfer of domain knowledge learned from a labeled source domain to unlabeled target domains, providing a way of coping with the difficulty of labeling in new domains. The majority of prior work has relied on both source and target domain data for adaptation. However, because of privacy concerns about potential leaks in sensitive information contained in patient data, it is often challenging to share the data and labels in the source domain and trained model parameters in cross-center collaborations. To address this issue, we propose a practical framework for UDA with a black-box segmentation model trained in the source domain only, without relying on source data or a white-box source model in which the network parameters are accessible. In particular, we propose a knowledge distillation scheme to gradually learn target-specific representations. Additionally, we regularize the confidence of the labels in the target domain via unsupervised entropy minimization, leading to performance gain over UDA without entropy minimization. We extensively validated our framework on a few datasets and deep learning backbones, demonstrating the potential for our framework to be applied in challenging yet realistic clinical settings.

15.
IEEE Trans Image Process ; 31: 2710-2725, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35324441

RESUMO

Inspired by the recent PointHop classification method, an unsupervised 3D point cloud registration method, called R-PointHop, is proposed in this work. R-PointHop first determines a local reference frame (LRF) for every point using its nearest neighbors and finds local attributes. Next, R-PointHop obtains local-to-global hierarchical features by point downsampling, neighborhood expansion, attribute construction and dimensionality reduction steps. Thus, point correspondences are built in hierarchical feature space using the nearest neighbor rule. Afterwards, a subset of salient points with good correspondence is selected to estimate the 3D transformation. The use of the LRF allows for invariance of the hierarchical features of points with respect to rotation and translation, thus making R-PointHop more robust at building point correspondence, even when the rotation angles are large. Experiments are conducted on the 3DMatch, ModelNet40, and Stanford Bunny datasets, which demonstrate the effectiveness of R-PointHop for 3D point cloud registration. R-PointHop's model size and training time are an order of magnitude smaller than those of deep learning methods, and its registration errors are smaller, making it a green and accurate solution. Our codes are available on GitHub (https://github.com/pranavkdm/R-PointHop).

16.
Osteoarthritis Cartilage ; 30(5): 702-713, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35122943

RESUMO

OBJECTIVE: To examine the clusters of chronic conditions present in people with osteoarthritis and the associated risk factors and health outcomes. METHODS: Clinical Practice Research Datalink (CPRD) GOLD was used to identify people diagnosed with incident osteoarthritis (n = 221,807) between 1997 and 2017 and age (±2 years), gender, and practice matched controls (no osteoarthritis, n = 221,807) from UK primary care. Clustering of people was examined for 49 conditions using latent class analysis. The associations between cluster membership and covariates were quantified by odds ratios (OR) using multinomial logistic regression. General practice (GP) consultations, hospitalisations, and all-cause mortality rates were compared across the clusters identified at the time of first diagnosis of osteoarthritis (index date). RESULTS: In both groups, conditions largely grouped around five clusters: relatively healthy; cardiovascular (CV), musculoskeletal-mental health (MSK-MH), CV-musculoskeletal (CV-MSK) and metabolic (MB). In the osteoarthritis group, compared to the relatively healthy cluster, strong associations were seen for 1) age with all clusters; 2) women with the MB cluster (OR 5.55: 5.14-5.99); 3) obesity with the CV-MSK (OR 2.11: 2.03-2.20) and CV clusters (OR 2.03: 1.97-2.09). The CV-MSK cluster in the osteoarthritis group had the highest number of GP consultations and hospitalisations, and the mortality risk was 2.45 (2.33-2.58) times higher compared to the relatively healthy cluster. CONCLUSIONS: Of the five identified clusters, CV-MSK, CV, and MSK-MH are more common in OA and CV-MSK cluster had higher health utilisation. Further research is warranted to better understand the mechanistic pathways and clinical implications.


Assuntos
Medicina Geral , Osteoartrite , Análise por Conglomerados , Comorbidade , Feminino , Humanos , Osteoartrite/epidemiologia , Reino Unido/epidemiologia
17.
IEEE J Biomed Health Inform ; 26(7): 3185-3196, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35139030

RESUMO

Modeling statistical properties of anatomical structures using magnetic resonance imaging is essential for revealing common information of a target population and unique properties of specific subjects. In brain imaging, a statistical brain atlas is often constructed using a number of healthy subjects. When tumors are present, however, it is difficult to either provide a common space for various subjects or align their imaging data due to the unpredictable distribution of lesions. Here we propose a deep learning-based image inpainting method to replace the tumor regions with normal tissue intensities using only a patient population. Our framework has three major innovations: 1) incompletely distributed datasets with random tumor locations can be used for training; 2) irregularly-shaped tumor regions are properly learned, identified, and corrected; and 3) a symmetry constraint between the two brain hemispheres is applied to regularize inpainted regions. Henceforth, regular atlas construction and image registration methods can be applied using inpainted data to obtain tissue deformation, thereby achieving group-specific statistical atlases and patient-to-atlas registration. Our framework was tested using the public database from the Multimodal Brain Tumor Segmentation challenge. Results showed increased similarity scores as well as reduced reconstruction errors compared with three existing image inpainting methods. Patient-to-atlas registration also yielded better results with improved normalized cross-correlation and mutual information and a reduced amount of deformation over the tumor regions.


Assuntos
Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Encéfalo/diagnóstico por imagem , Humanos , Processamento de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos
19.
J Nutr Health Aging ; 26(1): 6-12, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35067697

RESUMO

OBJECTIVES: Frailty is a significant public health and clinical issue among the elder population. This study aimed to evaluate the nutritional status and renal function in relation to frailty among elderly Taiwanese. DESIGN: We administered community-based health surveys to the elder population in Chiayi County, Taiwan, from 2017 to 2019. MEASUREMENTS: We measured nutritional status (including serum albumin and total protein levels), renal function (including serum blood urea nitrogen, creatinine, urine protein, and urine creatinine levels), hand grip strength (GS) and calculated appendicular muscle mass (AMM). RESULTS: The study recruited 3739 participants (2139 women). Participants of both sexes with normal GS had higher serum albumin levels and lower urine protein/creatinine ratios (UPCRs). For the men with normal and weak GS, serum albumin levels were 4.15 ± 0.2 and 4.10 ± 0.2 g/dL (p < 0.01), and UPCRs were 123.1 ± 219.6 and 188.7 ± 366.2 (p < 0.001), respectively. GS was positively correlated with serum albumin and urine creatinine levels (r = 0.136 and 0.177, both p < 0.001). AMM was also positively correlated with serum albumin and urine creatinine levels (r = 0.078 and 0.091, both p < 0.001). In the multivariate regression model, for every 1 g/dL increase in serum albumin level, there was a 1.9 and 1.7-kg increase in GS for men and women (p < 0.05 and p < 0.01), respectively. The final model for predicting GS included age, albumin, BUN, and UPCR (urine creatinine for women) which presented a variance of 22.1% and 13.8%, respectively. CONCLUSION: Proper dietary nutritional intake and maintaining renal function are key elements for preventing frailty among elder population in Taiwan.


Assuntos
Fragilidade , Idoso , Creatinina , Estudos Transversais , Feminino , Fragilidade/epidemiologia , Força da Mão , Humanos , Vida Independente , Rim/fisiologia , Masculino , Estado Nutricional
20.
Med Image Comput Comput Assist Interv ; 13435: 66-76, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36780245

RESUMO

Unsupervised domain adaptation (UDA) has been vastly explored to alleviate domain shifts between source and target domains, by applying a well-performed model in an unlabeled target domain via supervision of a labeled source domain. Recent literature, however, has indicated that the performance is still far from satisfactory in the presence of significant domain shifts. Nonetheless, delineating a few target samples is usually manageable and particularly worthwhile, due to the substantial performance gain. Inspired by this, we aim to develop semi-supervised domain adaptation (SSDA) for medical image segmentation, which is largely underexplored. We, thus, propose to exploit both labeled source and target domain data, in addition to unlabeled target data in a unified manner. Specifically, we present a novel asymmetric co-training (ACT) framework to integrate these subsets and avoid the domination of the source domain data. Following a divide-and-conquer strategy, we explicitly decouple the label supervisions in SSDA into two asymmetric sub-tasks, including semi-supervised learning (SSL) and UDA, and leverage different knowledge from two segmentors to take into account the distinction between the source and target label supervisions. The knowledge learned in the two modules is then adaptively integrated with ACT, by iteratively teaching each other, based on the confidence-aware pseudo-label. In addition, pseudo label noise is well-controlled with an exponential MixUp decay scheme for smooth propagation. Experiments on cross-modality brain tumor MRI segmentation tasks using the BraTS18 database showed, even with limited labeled target samples, ACT yielded marked improvements over UDA and state-of-the-art SSDA methods and approached an "upper bound" of supervised joint training.

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