Search

The inherent speckle which is attached to any coherent imaging system affects the analysis and interpretation of synthetic aperture radar (SAR) images. To take advantage of well-registered multi-temporal SAR images, we improve the adaptive nonlocal temporal filter with state-of-the-art adaptive denoising methods and propose a patch based adaptive temporal filter. To address the bias problem of the denoising results, we propose a fast and efficient multitemporal despeckling method. The key idea of the proposed approach is the use of the ratio image, provided by the ratio between an image and the temporal mean of the stack. This ratio image is easier to denoise than a single image thanks to its improved stationarity. Besides, temporally stable thin structures are well-preserved thanks to the multi-temporal mean. Without reference image, we propose to use a patch-based auto-covariance residual evaluation method to examine the residual image and look for possible remaining structural contents. With speckle reduction images, we propose to use simplified generalized likelihood ratio method to detect the change area, change magnitude and change times in long series of well-registered images. Based on spectral clustering, we apply the simplified generalized likelihood ratio to detect the time series change types. Then, jet colormap and HSV colorization may be used to vividly visualize the detection results. These methods have been successfully applied to monitor farmland area, urban area, harbor region, and flooding area changes., Le bruit de chatoiement (speckle) lié aux systèmes d'imagerie cohérente a des conséquences sur l'analyse et l'interprétation des images radar à synthèse d'ouverture (RSO). Pour corriger ce défaut, nous profitons de séries temporelles d'images RSO bien recalées. Nous améliorons le filtre adaptatif temporel non-local à l'aide de méthodes performantes de débruitage adaptatif et proposons un filtrage temporel adaptatif basé sur les patchs. Pour réduire le biais du débruitage, nous proposons une méthode originale, rapide et efficace de débruitage multitemporel. L'idée principale de l'approche proposée est d'utiliser l'image dite "de ratio", donnée par le rapport entre l'image et la moyenne temporelle de la pile. Cette image de ratio est plus facile à débruiter qu'une image isolée en raison de sa meilleure stationnarité. Par ailleurs, les structures fines stables dans le temps sont bien préservées grâce au moyennage multitemporel. Disposant d'images débruitées, nous proposons ensuite d'utiliser la méthode du rapport de vraisemblance généralisé simplifié pour détecter les zones de changement ainsi que l'amplitude des changements et les instants de changements intéressants dans de longues séries d'images correctement recalées. En utilisant le partitionnement spectral, on applique le rapport de vraisemblance généralisé simplifié pour caractériser les changements des séries temporelles. Nous visualisons les résultats de détection en utilisant l'échelle de couleur 'jet' et une colorisation HSV. Ces méthodes ont été appliquées avec succès pour étudier des zones cultivées, des zones urbaines, des régions portuaires et des changements dus à des inondations.

The XIENCE V USA (XIENCE V Everolimus Eluting Coronary Stent System Condition-of-Approval Post-Market Study) sought to evaluate the safety of everolimus-eluting coronary stent systems in a real-world population with a total of 5,054 participants (1,875 standard-risk; 3,179 extended-risk). At 1 year, the rate of Academic Research Consortium-defined definite and probable stent thrombosis was 0.84%, and the composite rate of cardiac death and Academic Research Consortium-defined myocardial infarction was 6.5%. Consistent safety outcomes between the matched standard-risk cohorts from the XIENCE V USA study and the SPIRIT IV randomized trial (Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System in the Treatment of Subjects With de Novo Native Coronary Artery Lesions) suggest that this study affords a reliable benchmark for understanding the safety of everolimus-eluting coronary stent systems in real-world clinical practice.ObjectivesThe XIENCE V USA (XIENCE V Everolimus Eluting Coronary Stent System Condition-of-Approval Post-Market study) sought to: 1) evaluate the safety of everolimus-eluting coronary stent systems (EECSS) in a contemporary cohort of real-world subjects; and 2) prospectively test the quality of event reporting with analysis of matched patients from the randomized SPIRIT IV (Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System in the Treatment of Subjects With de Novo Native Coronary Artery Lesions) trial.BackgroundRandomized trials have demonstrated the safety and efficacy of EECSS in selected “standard-risk” patients.MethodsThe XIENCE V USA trial was a prospective, multicenter, single-arm study in unselected patients. The primary endpoint was Academic Research Consortium (ARC)-defined definite and probable stent thrombosis (ST); the co-primary endpoint was the composite of cardiac death and myocardial infarction at 1 year. Secondary analyses included: 1) stratification by standard-risk and extended-risk cohorts; and 2) late ST after dual antiplatelet therapy interruption.ResultsOf 5,054 participants (1,875 standard-risk; 3,179 extended-risk), 4,958 (98.1%) reached 1-year follow-up. The rate of ARC-defined definite and probable ST was 0.84% (95% confidence interval [CI]: 0.60% to 1.14%) in the overall population and 0.33% (95% CI: 0.12% to 10.72%) and 1.14% (95% CI: 0.80% to 11.58%) in the standard-risk and extended-risk cohorts, respectively. No late ST was observed after dual antiplatelet therapy interruption in either cohort after 6 months. The composite rate of cardiac death and ARC-defined myocardial infarction was 6.5% (95% CI: 5.79% to 17.17%) in the overall population, 3.8% (95% CI: 2.98% to 14.78%) in the standard-risk cohort, and 8.0% (95% CI: 7.09% to 19.02%) in the extended-risk cohort.ConclusionsThis study comprehensively reports ST rates for EECSS in a contemporary real-world population. The absence of ST after dual antiplatelet therapy interruption beyond 6 months in standard-risk and high-risk patients is notable. Consistent safety outcomes between matched standard-risk cohorts from the XIENCE V USA study and the SPIRIT IV randomized trial suggest that this study affords a reliable benchmark for understanding the safety of EECSS in the context of real-world clinical practice. (XIENCE V Everolimus Eluting Coronary Stent System [EECSS] USA Post-Approval Study; NCT00676520)

ObjectivesThe aim of this study was to identify predictors of clinical events after XIENCE V (Abbott Vascular, Santa Clara, California) stenting.BackgroundThe XIENCE V USA (XIENCE V Everolimus Eluting Coronary Stent System [EECSS] USA Post-Approval) study is a prospective, multicenter, Food and Drug Administration-required post-approval study to examine safety and effectiveness in real-world settings. After an initial 5,062 patients, 2,999 more were included as part of the DAPT (Dual Antiplatelet Therapy) trial (total n = 8,061).MethodsOne-year clinical events, including stent thrombosis (ST), cardiac death/myocardial infarction (MI), target lesion failure, and target lesion revascularization, were adjudicated according to Academic Research Consortium criteria, with ST and cardiac death/MI as primary and co-primary endpoints. Demographic, clinical, and procedural variables were assessed by multivariable analysis. A time-dependent covariate assessed the association between DAPT usage and ST.ResultsRoughly 61% were off-label; 85.6% remained on DAPT without interruption through 1 year. Incidences of definite/probable ST, cardiac death/MI, target lesion failure, and target lesion revascularization were 0.80% (95% confidence interval [CI]: 0.61% to 1.03%), 7.1% (95% CI: 6.51% to 7.68%), 8.9% (95% CI: 8.30% to 9.60%), and 4.3% (95% CI: 3.82% to 4.75%), respectively. Several independent clinical and angiographic predictors were identified for each outcome. Predictors of ST included DAPT interruption ≤30 days (hazard ratio [HR]: 8.63, 95% CI: 2.69 to 27.73, p = 0.0003), renal insufficiency (HR: 3.72, 95% CI: 1.71 to 8.09, p = 0.0009), and total stent length (HR: 1.30, 95% CI: 1.16 to 1.47, p < 0.0001). A DAPT interruption >30 days was not predictive of ST.ConclusionsIn this large, real-world population, XIENCE V demonstrated low event rates at 1 year, with several independent predictors. Early DAPT interruption (≤30 days) was the most potent predictor of ST, whereas delayed interruption (>30 days) was not predictive. (XIENCE V Everolimus Eluting Coronary Stent System [EECSS] USA Post-Approval Study; NCT00676520)

Background: Recent studies have reported that machine learning (ML), with a relatively strong capacity for processing non-linear data and adaptive ability, could improve the accuracy and efficiency of prediction. The article summarizes the published studies on ML models that predict motor function 3-6 months post-stroke., Methods: A systematic literature search was conducted in PubMed, Embase, Cochorane and Web of Science as of April 3, 2023 for studies on ML prediction of motor function in stroke patients. The quality of the literature was assessed using the Prediction model Risk Of Bias Assessment Tool (PROBAST). A random-effects model was preferred for meta-analysis using R4.2.0 because of the different variables and parameters., Results: A total of 44 studies were included in this meta-analysis, involving 72,368 patients and 136 models. Models were categorized into subgroups according to the predicted outcome Modified Rankin Scale cut-off value and whether they were constructed based on radiomics. C-statistics, sensitivity, and specificity were calculated. The random-effects model showed that the C-statistics of all models were 0.81 (95% CI: 0.79; 0.83) in the training set and 0.82 (95% CI: 0.80; 0.85) in the validation set. According to different Modified Rankin Scale cut-off values, C-statistics of ML models predicting Modified Rankin Scale>2(used most widely) in stroke patients were 0.81 (95% CI: 0.78; 0.84) in the training set, and 0.84 (95% CI: 0.81; 0.87) in the validation set. C-statistics of radiomics-based ML models in the training set and validation set were 0.81 (95% CI: 0.78; 0.84) and 0.87 (95% CI: 0.83; 0.90), respectively., Conclusion: ML can be used as an assessment tool for predicting the motor function in patients with 3-6 months of post-stroke. Additionally, the study found that ML models with radiomics as a predictive variable were also demonstrated to have good predictive capabilities. This systematic review provides valuable guidance for the future optimization of ML prediction systems that predict poor motor outcomes in stroke patients., Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display&#95;record.php?ID=CRD42022335260, identifier: CRD42022335260., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Li, Chi, Zhao, Wu, Jiao, Zheng, Zhang and Li.)