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Implementation of multiphase computed tomography angiography in management of patients with acute ischemic stroke in clinical practice
摘要： Multiphase computed tomography angiography (CTA) provides information on the status of major cranial arteries and extent of brain collateralization. The purpose of the study was to determine whether implementation of multiphase CTA in routine clinical practice was feasible, safe and useful. Patients with acute ischemic stroke (NIHSS (cid:1) 6) were included. Multiphase CTA was performed. Duration of performing multiphase CTA, inter-rater correlation and incidence of contrast-induced nephropathy (CIN) were studied. Infarct volume, incidence of hemorrhagic transformation, the rates of favorable outcome and death were compared between those with poor and intermediate-good collateralization. Multiphase CTA was performed in 108 patients. Mean duration on each multiphase CTA study was 4.8 min. Inter-rater reliability was intermediate-good (weighted kappa 0.7569, p < 0.001). CIN occurred in 3 patients (2.8%). There were no major intracranial/extracranial artery occlusion in 31 patients (29%) and there were severe stenosis or occlusions in 77 patients (71%). In the subgroup of patients with major artery severe stenosis or occlusion, 36 patients (36/77, 47%) had poor collateralization. Despite non-signi?cant difference in acute treatment, the patients with poor collateralization had larger infarct (123 vs 35 cc, p < 0.001) and poorer outcomes (mean modi?ed Rankin scale 3.86 vs 2.73, p = 0.011), while the differences in symptomatic hemorrhagic transformation (2.6 vs 7%, p = 0.385) and death rate (14 vs 12%, p = 0.825) were non-signi?cant, as compared to those with intermediate-good collateralization. Multiphase CTA was feasible and safe. Besides the status of major arteries, multiphase CTA provided information on collateralization, which was associated with the size of infarct and clinical outcomes.
关键词： Multiphase CTA,Asian,Thai,Acute stroke,Computed tomography angiography,Ischemic stroke
更新于2025-09-23 15:23:52
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[Lecture Notes in Computational Vision and Biomechanics] Computer Aided Intervention and Diagnostics in Clinical and Medical Images Volume 31 || Retina as a Biomarker of Stroke
摘要： Stroke is one of the significant reasons of adult impairment in most of the developing nations worldwide. Various imaging modalities are used to diagnose stroke during its initial hours of occurrence. But early prediction of stroke is still a challenge in the field of biomedical research. Since retinal arterioles share similar anatomical, physiological, and embryological attributes with brain arterioles, analysis of retinal fundus images can be of great significance in stroke prognosis. This research work mainly analyzes the variations in retinal vasculature in predicting the risk of stroke. Fractal dimension, branching coefficients and angle, asymmetry factor and optimality ratio for both arteries and veins were computed from the processed input image and given to a support vector machine classifier which gives promising results.
关键词： Support vector machine,Stroke,Retinal fundus images
更新于2025-09-23 15:23:52
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[Communications in Computer and Information Science] Advances in Signal Processing and Intelligent Recognition Systems Volume 968 (4th International Symposium SIRS 2018, Bangalore, India, September 19–22, 2018, Revised Selected Papers) || A Novel Method for Stroke Prediction from Retinal Images Using HoG Approach
摘要： Stroke is one of the principal reasons for adult impairment worldwide. Retinal fundus images are analyzed for the detection of various cardiovascular diseases like Stroke. Stroke is mainly characterized by soft and hard exudates, artery or vein occlusion and alterations in retinal vasculature. In this research work, Histogram of Oriented Gradients (HoG) has been implemented to extract features from the region of interest of retinal fundus images. This innovative method is assessed for the computer aided diagnosis of normal healthy and abnormal images of stroke patients. A comparative analysis has been made between the extracted HoG features and Haralick features. HoG features extracted from the region of interest, when given to a Na?ve Bayes classifier provides an accuracy of 93% and a Receiver Operating Characteristic (ROC) curve area of 0.979.
关键词： Haralick features,Na?ve Bayes classifier,Histogram of Oriented Gradients (HoG),Stroke
更新于2025-09-23 15:23:52
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Stroke diagnosis from retinal fundus images using multi texture analysis
摘要： Stroke is a cerebrovascular disease which is one of the significant causes of adult impairment. Research shows that retinal fundus images carry vital information for the prediction of various cardiovascular diseases like Stroke. This work investigates a multi-texture description for the computer aided diagnosis of Stroke from retinal fundus images. Texture of the retinal background is analyzed, thereby eliminating the need for segmentation. Gabor Filter (GF), Local Binary Pattern (LBP) and Histogram of Oriented gradients (HOG) are the texture descriptors implemented in this work. The texture descriptors are applied to the second Eigen channel obtained by Principal Component Analysis (PCA). Extracted features are concatenated to form a multi-texture representation and dimensionality reduction is done by ReliefF feature selection method. The compact feature vector is given to Na?ve Bayes classifier and performance metrics are evaluated. We have evaluated the performance of individual feature descriptors and multiple feature descriptors in retinal fundus images for stroke diagnosis. Multi-texture description outperforms individual texture descriptors by an accuracy of 95.1 %.
关键词： Gabor filter,ReliefF,histogram of oriented gradients,principal component analysis,local binary pattern,Stroke
更新于2025-09-23 15:22:29
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Training of Hand Rehabilitation Using Low Cost Exoskeleton and Vision-Based Game Interface
摘要： Motivating game-based training have the potential to improve therapy for people with neurological impairments. In recent years, the serious games have become extremely useful tools in rehabilitation field. They aim to stimulate the mobility of the body through an immersive experience that puts the user in interactive virtual environment. This paper is concerned about developing a customized augmented reality system for stroke rehabilitation. This will be done through integrating an interactive serious game interface with a hand exoskeleton device. This game-based rehabilitation system allows users to carry out physical rehabilitation therapies using a natural user interface based on Kinect’s skeletal tracking features and the electromyography (EMG) sensor. During game playing, the interactive user interface provides useful real-time feedback information such as the time required to grasp a desired dynamic virtual object, and the assigned score and thus the ability of the proposed system to provide a compensatory action regarding the dynamic behavior of the virtual target. The main goal of the developed virtual environment is to create positive influences on the rehabilitation process. Patient movement information and signals obtained from the developed exoskeleton device are used together to monitor the rehabilitation progress. The developed exoskeleton hand is a 3D printed low cost device suitable for grasping tasks that can be used even for domestic stroke patients. The developed exoskeleton device is not only a mechanical system able to perform the rehabilitation act but also it presents an effective tracking and traceability software solution. The EMG signals measured during hand motion are used to detect the intention of hand opening or closing which in turn will actuate the mechanical structure to accomplish the desired task. Parameters and results of patients’ exercises are stored and analyzed when needed to evaluate patients’ progress. The developed system is tested experimentally and it is able to restore the functions of the upper limb and mainly give patients more motivation to undergo the rehabilitation exercises.
关键词： Robotic exoskeleton,EMG control,Kinect sensor,3D printing,Stroke rehabilitation
更新于2025-09-23 15:22:29
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[IEEE 2018 25th IEEE International Conference on Image Processing (ICIP) - Athens, Greece (2018.10.7-2018.10.10)] 2018 25th IEEE International Conference on Image Processing (ICIP) - Sketchpointnet: A Compact Network for Robust Sketch Recognition
摘要： Sketch recognition is a challenging image processing task. In this paper, we propose a novel point-based network with a compact architecture, named SketchPointNet, for robust sketch recognition. Sketch features are hierarchically learned from three miniPointNets, by successively sampling and grouping 2D points in a bottom-up fashion. SketchPointNet exploits both temporal and spatial context in strokes during point sampling and grouping. By directly consuming the sparse points, SketchPointNet is very compact and efficient. Compared with state-of-the-art techniques, SketchPointNet achieves comparable performance on the challenging TU-Berlin dataset while it significantly reduces the network size.
关键词： point set,stroke pattern,Sketch recognition,deep neural network
更新于2025-09-23 15:22:29
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Photoacoustic microscopy reveals the hemodynamic basis of sphingosine 1-phosphate-induced neuroprotection against ischemic stroke
摘要： Rationale: Emerging evidence has suggested that sphingosine 1-phosphate (S1P), a bioactive metabolite of sphingolipids, may play an important role in the pathophysiological processes of cerebral hypoxia and ischemia. However, the influence of S1P on cerebral hemodynamics and metabolism remains unclear. Material and Methods: Uniquely capable of high-resolution, label-free, and comprehensive imaging of hemodynamics and oxygen metabolism in the mouse brain without the influence of general anesthesia, our newly developed head-restrained multi-parametric photoacoustic microscopy (PAM) is well suited for this mechanistic study. Here, combining the cutting-edge PAM and a selective inhibitor of sphingosine kinase 2 (SphK2) that can increase the blood S1P level, we investigated the role of S1P in cerebral oxygen supply-demand and its neuroprotective effects on global brain hypoxia induced by nitrogen gas inhalation and focal brain ischemia induced by transient middle cerebral artery occlusion (tMCAO). Results: Inhibition of SphK2, which increased the blood S1P, resulted in the elevation of both arterial and venous sO2 in the hypoxic mouse brain, while the cerebral blood flow remained unchanged. As a result, it gradually and significantly reduced the metabolic rate of oxygen. Furthermore, pre-treatment of the mice subject to tMCAO with the SphK2 inhibitor led to decreased infarct volume, improved motor function, and reduced neurological deficit, compared to the control treatment with a less potent R-enantiomer. In contrast, post-treatment with the inhibitor showed no improvement in the stroke outcomes. The failure for the post-treatment to induce neuroprotection was likely due to the relatively slow hemodynamic responses to the SphK2 inhibitor-evoked S1P intervention, which did not take effect before the brain injury was induced. Conclusions: Our results reveal that elevated blood S1P significantly changes cerebral hemodynamics and oxygen metabolism under hypoxia but not normoxia. The improved blood oxygenation and reduced oxygen demand in the hypoxic brain may underlie the neuroprotective effect of S1P against ischemic stroke.
关键词： Sphingosine 1-phosphate,Photoacoustic microscopy,Neuroprotection,Hypoxia,Ischemic stroke
更新于2025-09-23 15:22:29
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Imaging Considerations in Pregnancy
摘要： Pregnancy is a complex interplay of multiple physiologic states maintaining balance between the needs of mother and fetus. This is reflected in hormonal, hemodynamic, hematologic, and immunologic changes at both global and cellular levels. A decrease in brain size and increase in heart, pituitary, thyroid, and kidney sizes secondary to hormonal influences have been observed during pregnancy.1,2 Circulating hormones also have trophic effect on preexisting neoplasms, such as meningioma, pituitary adenomas, and breast carcinoma.3 The increased blood volume and clotting factor alterations increase the risk of stroke, especially during the peripartum and postpartum period.4,5 Hemodynamic and hormonal effects on vessel wall integrity can lead to worsening of aneurysm with possible hemorrhage, whereas prolonged labor may increase risk of infarct from venous thrombosis or dissection.6,7 In contrast, increased cortisol levels have shown to improve autoimmune diseases such as multiple sclerosis by exerting inhibitory effect on T-cell function8–10
关键词： Radiation safety,Pregnancy,Imaging,RCVS,Stroke,PRES,Eclampsia
更新于2025-09-23 15:21:21
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Step Sizes and Rate Constants of Single-headed Cytoplasmic Dynein Measured with Optical Tweezers
摘要： A power stroke of dynein is thought to be responsible for the stepping of dimeric dynein. However, the actual size of the displacement driven by a power stroke has not been directly measured. Here, the displacements of single-headed cytoplasmic dynein were measured by optical tweezers. The mean displacement of dynein interacting with microtubule was ~8 nm at 100 μM ATP, and decreased sigmoidally with a decrease in the ATP concentration. The ATP dependence of the mean displacement was explained by a model that some dynein molecules bind to microtubule in pre-stroke conformation and generate 8-nm displacement, while others bind in the post-stroke one and detach without producing a power stroke. Biochemical assays showed that the binding affinity of the post-stroke dynein to a microtubule was ~5 times higher than that of pre-stroke dynein, and the dissociation rate was ~4 times lower. Taking account of these rates, we conclude that the displacement driven by a power stroke is 8.3 nm. A working model of dimeric dynein driven by the 8-nm power stroke was proposed.
关键词： power stroke,optical tweezers,ATP,microtubule,dynein
更新于2025-09-23 15:21:21
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Corneal Confocal Microscopy detects a Reduction in Corneal Endothelial Cells and Nerve Fibres in Patients with Acute Ischemic Stroke
摘要： Endothelial dysfunction and damage underlie cerebrovascular disease and ischemic stroke. We undertook corneal confocal microscopy (CCM) to quantify corneal endothelial cell and nerve morphology in 146 patients with an acute ischemic stroke and 18 age-matched healthy control participants. Corneal endothelial cell density was lower (P < 0.001) and endothelial cell area (P < 0.001) and perimeter (P < 0.001) were higher, whilst corneal nerve fibre density (P < 0.001), corneal nerve branch density (P < 0.001) and corneal nerve fibre length (P = 0.001) were lower in patients with acute ischemic stroke compared to controls. Corneal endothelial cell density, cell area and cell perimeter correlated with corneal nerve fiber density (P = 0.033, P = 0.014, P = 0.011) and length (P = 0.017, P = 0.013, P = 0.008), respectively. Multiple linear regression analysis showed a significant independent association between corneal endothelial cell density, area and perimeter with acute ischemic stroke and triglycerides. CCM is a rapid non-invasive ophthalmic imaging technique, which could be used to identify patients at risk of acute ischemic stroke.
关键词： Corneal Confocal Microscopy,corneal endothelial cells,acute ischemic stroke,corneal nerve fibres
更新于2025-09-23 15:21:21