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35 results on '"Wong, Ka-Sing"'

2. Hemodynamics and stroke risk in intracranial atherosclerotic disease

Author

Leng, Xinyi, primary, Lan, Linfang, additional, Ip, Hing Lung, additional, Abrigo, Jill, additional, Scalzo, Fabien, additional, Liu, Haipeng, additional, Feng, Xueyan, additional, Chan, Ka Lung, additional, Fan, Florence S. Y., additional, Ma, Sze Ho, additional, Fang, Hui, additional, Xu, Yuming, additional, Li, Jingwei, additional, Zhang, Bing, additional, Xu, Yun, additional, Soo, Yannie O. Y., additional, Mok, Vincent C. T., additional, Yu, Simon C. H., additional, Liebeskind, David S., additional, Wong, Ka Sing, additional, and Leung, Thomas W., additional

Published
2019
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3. Hemodynamic Impact of Systolic Blood Pressure and Hematocrit Calculated by Computational Fluid Dynamics in Patients with Intracranial Atherosclerosis

Author

Nam, Hyo Suk, primary, Scalzo, Fabien, additional, Leng, Xinyi, additional, Ip, Hing Lung, additional, Lee, Hye Sun, additional, Fan, Florence, additional, Chen, Xiangyan, additional, Soo, Yannie, additional, Miao, Zhongrong, additional, Liu, Liping, additional, Feldmann, Edward, additional, Leung, Thomas, additional, Wong, Ka Sing, additional, and Liebeskind, David S., additional

Published
2015
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5. Evolution of intracranial atherosclerotic disease under modern medical therapy

Author

Leung, Thomas W., primary, Wang, Lily, additional, Soo, Yannie O. Y., additional, Ip, Vincent H. L., additional, Chan, Anne Y. Y., additional, Au, Lisa W. C., additional, Fan, Florence S. Y., additional, Lau, Alex Y. L., additional, Leung, Howan, additional, Abrigo, Jill, additional, Wong, Adrian, additional, Mok, Vincent C. T., additional, Ng, Ping Wing, additional, Tsoi, Tak Hong, additional, Li, Siu Hung, additional, Man, Celeste B. L., additional, Fong, Wing Chi, additional, Wong, Ka Sing, additional, and Yu, Simon C. H., additional

Published
2015
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6. Persistent Benign Oligemia Causes CT Perfusion Mismatch in Patients with Intracranial Large Artery Occlusive Disease during Subacute Stroke

Author

Li, Jing-Jing, primary, Chen, Xiang-Yan, additional, Soo, Yannie, additional, Abrigo, Jill M., additional, Leung, Thomas W., additional, Wong, Edward, additional, Mok, Vincent, additional, Cheung, James S.W., additional, Ahuja, Anil T., additional, Zeng, Jin-Sheng, additional, and Wong, Ka-Sing, additional

Published
2013
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8. Predictors for cognitive decline in patients with confluent white matter hyperintensities

Author

Mok, Vincent, primary, Xiong, Yunyun, additional, Wong, Kelvin K., additional, Wong, Adrian, additional, Schmidt, Reinhold, additional, Chu, Winnie W.C., additional, Hu, Xintao, additional, Lung Leung, Eric Yim, additional, Chen, Sirong, additional, Chen, Yangkun, additional, Tang, Wai Kwong, additional, Chen, Xiangyan, additional, Ho, Chi Lai, additional, Wong, Ka Sing, additional, and Wong, Stephen T.C., additional

Published
2012
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10. Association of a genetic variant in the apolipoprotein A5 gene with the metabolic syndrome in Chinese

Author

Ong, Kwok Leung, primary, Jiang, Chao Qiang, additional, Liu, Bin, additional, Jin, Ya Li, additional, Tso, Annette W.K., additional, Tam, Sidney, additional, Wong, Ka Sing, additional, Tomlinson, Brian, additional, Cheung, Bernard M.Y., additional, Lin, Jie Ming, additional, Yue, Xiao Jun, additional, Lam, Karen S.L., additional, Lam, Tai Hing, additional, and Thomas, Graham Neil, additional

Published
2011
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26. Can IQCODE detect poststroke dementia?

Author

Tang, Wai Kwong, primary, Chan, Sandra S. M., additional, Chiu, Helen F. K., additional, Wong, Ka Sing, additional, Kwok, Timothy C. Y., additional, Mok, Vincent, additional, and Ungvari, Gabor S., additional

Published
2003
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32. Hemodynamic Impact of Systolic Blood Pressure and Hematocrit Calculated by Computational Fluid Dynamics in Patients with Intracranial Atherosclerosis.

Author

Nam HS, Scalzo F, Leng X, Ip HL, Lee HS, Fan F, Chen X, Soo Y, Miao Z, Liu L, Feldmann E, Leung T, Wong KS, and Liebeskind DS

Subjects
Aged, Aged, 80 and over, Angiography, Digital Subtraction, Computed Tomography Angiography, Female, Humans, Male, Middle Aged, Stroke physiopathology, Blood Pressure physiology, Computer Simulation, Hematocrit, Hemodynamics physiology, Hydrodynamics, Intracranial Arteriosclerosis physiopathology, Software
Abstract

Objective: Success in clinical trials of intracranial atherosclerosis (ICAS) is related to accurate identification of high-risk patients. Noninvasive computational fluid dynamics (CFD) of stenotic lesions may enhance therapeutic decision-making. We determined whether physiologic parameters change downstream cerebral hemodynamics in patients with ICAS., Methods: Consecutive ICAS patients who underwent both CT angiography (CTA) and digital subtraction angiography were enrolled. CFD models were made using CTA source images. Inlet boundary conditions were defined using three ranges of systolic blood pressure (BP) (109.2, 158, and 225 mmHg) and hematocrit (27.3, 40.2, and 48.8). Ratios of pressure, shear strain rates (SSR), and flow velocity across the lesion were calculated using CFD simulations. A linear mixed model was used for the statistical analysis of repeated simulations., Results: Among the 56 patients, 32 had moderate stenosis (50-69%) and 24 had severe stenosis (70-99%). A linear mixed model revealed that the ratio of pressure was predicted by systolic BP and stenosis group interaction (P = .036). These pressure decreases were associated with systolic BP (P < .001) and stenosis group (P < .001), but not with hematocrit (P = .337). Post-hoc analysis revealed that pressure decreases were more profound in the severe stenosis than the moderate stenosis group when comparing high and low systolic BP (P = .0108). Ratios of SSR and velocity were only associated in the stenosis group., Conclusions: Our study showed that systolic BP along with the degree of stenosis was associated with pressure decreases across stenotic lesions. Physiologic conditions may superimpose further changes in post-stenotic or downstream blood flow., (Copyright © 2015 by the American Society of Neuroimaging.)

Published
2016
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33. Evaluation of age-related white matter changes using transcranial Doppler ultrasonography.

Author

Xiong YY, Mok V, Wong A, Leung T, Chen XY, Chu WC, Soo Y, Fu JH, Ding D, Hong Z, and Wong KS

Subjects
Age Distribution, Aged, Aged, 80 and over, Female, Hong Kong, Humans, Male, Middle Aged, Prevalence, Risk Factors, Nerve Fibers, Myelinated diagnostic imaging, Stroke epidemiology, Stroke pathology, Ultrasonography, Doppler, Transcranial statistics & numerical data
Abstract

Background: Age-related white matter changes (WMC) increase risk of cognitive and functional decline. They are considered as target for preventive trials. However, using magnetic resonance imaging (MRI) to screen for subclinical WMC is not cost-effective. We explored the clinical utility of transcranial Doppler ultrasound (TCD) in the evaluation of WMC. We hypothesized that the pulsatility index (PI) of TCD correlates with severity of WMC., Methods: Among 100 stroke patients with WMC, we obtained the mean PI of middle cerebral artery (MCA) and vertebral basilar artery (VB). We investigated the association between PI and WMC volume. We also obtained PI of 50 subjects who had no WMC on MRI and explored the ability of PI values in differentiating subjects with and without WMC., Results: Multivariate linear regressions found that mean MCA PI and mean VB PI were independent predictors for total WMC volume (beta = .43, P < .001 and beta = .37, P < .001, respectively). Mean MCA PI significantly differentiated patients with WMC from those without WMC (area under curve [AUC] .85 [95% confidence interval .78-.91]) with an optimal cut-off value at 1.15 that yielded sensitivity and specificity of 73.7% and 82%, respectively. AUC for mean VB PI was .81 (95% confidence interval .74-.88) with cut-off value at 1.06 that yielded sensitivity and specificity of 70% and 75%, respectively., Conclusions: PI correlates with volume of WMC. It may help to differentiate those with and without WMC in stroke patients. Further study evaluating the clinical utility of TCD in screening for subclinical WMC among community elderly is warranted., (Copyright © 2011 by the American Society of Neuroimaging.)

Published
2013
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34. Prognostic value of inflammatory mediators in 1-year outcome of acute ischemic stroke with middle cerebral artery stenosis.

Author

Gong X, Zou X, Liu L, Pu Y, Wang Y, Pan Y, Soo YO, Leung TW, Zhao X, Wang Y, and Wong KS

Subjects
Aged, C-Reactive Protein metabolism, Constriction, Pathologic diagnosis, Female, Follow-Up Studies, Humans, Magnetic Resonance Angiography, Magnetic Resonance Imaging, Male, Middle Aged, Predictive Value of Tests, Prognosis, Prospective Studies, Reproducibility of Results, Stroke blood, Stroke diagnosis, Treatment Outcome, Brain Ischemia pathology, Constriction, Pathologic pathology, Inflammation blood, Middle Cerebral Artery pathology, Stroke pathology
Abstract

Background and Purpose: Inflammation exists in inception, progression, and reperfusion of acute ischemic stroke. Insightful understanding of correlation in inflammatory mediators and stroke severity with intracranial artery stenosis may improve rational stroke therapy., Methods: We prospectively recruited 977 patients with acute noncardioembolic ischemic stroke with MCA stenosis by MRA as none to mild (<50%), moderate (50-69%), severe (70-99%), or occlusive (100%). The peripheral levels of WBC, homocysteine (HCY), and high sensitivity C-reactive protein (hs-CRP) were recorded. All patients were assessed of 1-year outcome by mRS as favorable (0-2) or poor (3-6)., Results: The levels of WBC, HCY, and hs-CRP had no significant differences in patients with categorized MCA stenosis (all P > 0.05). Higher levels of WBC, HCY, and hs-CRP were found in patients with 1-year poor outcome (all P < 0.05), but only hs-CRP is an independent predictor (OR 1.06, 95% CI 1.027-1.093, P = 0.0003). The combination of any two of increased hs-CRP (>3 mg/L), WBC (>6.91 × 10(9)/L), and HCY (>15  μ mol/L) had higher power in predicting 1-year poor outcome than the single elevated mediator., Conclusions: Elevated hs-CRP independently predicts 1-year poor outcome in acute stroke. The combination of increased hs-CRP, WBC, or HCY had a stronger predictive value in poor outcome than individual elevated mediator.

Published
2013
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35. Detection of the siphon internal carotid artery stenosis: transcranial Doppler versus digital subtraction angiography.

Author

You Y, Hao Q, Leung T, Mok V, Chen X, Lau A, Leung H, and Wong KS

Subjects
Adult, Aged, Aged, 80 and over, Angiography, Digital Subtraction, Blood Flow Velocity, Brain Ischemia diagnostic imaging, Female, Humans, Male, Middle Aged, ROC Curve, Sensitivity and Specificity, Stroke diagnostic imaging, Ultrasonography, Doppler, Transcranial, Carotid Artery, Internal diagnostic imaging, Carotid Stenosis diagnostic imaging
Abstract

Background: Transcranial Doppler (TCD) is widely applied to evaluate the intracranial large artery stenosis. We aimed to evaluate the accuracy of TCD in detecting siphon internal carotid artery (SICA) stenosis against digital subtraction angiography (DSA)., Methods: A total of 145 patients with TCD and DSA performed were recruited. The SICA and other intracranial arteries were evaluated through transorbital and transtemporal acoustic window by TCD. We defined the best cutoff value for significant SICA stenosis by receiver-operating characteristic (ROC) curve analyses and calculated the sensitivity, specificity, and positive and negative predictive values (PPV and NPV)., Results: Mean age of the patients was 65.7 years (range 28-88 years) and 75.1% (109/145) were men. The peak systolic velocity (PSV) = 120 cm/second had the largest area under the ROC curve (area under the ROC curve = .868) compared with the MFV = 70 cm/second and MFV = 80 cm/second (area under the ROC curve = .822 and .845). So the criteria for SICA stenoses were defined as PSV = 120 cm/second plus additional parameters (abnormal spectrum, circumscribed velocity changes, or side-to-side difference). Twenty-nine patients were diagnosed with SICA stenosis or occlusion on TCD. Fourteen patients had abnormal TCD findings that were not confirmed by DSA. One patient with normal TCD but DSA showed mild (40%) stenoses. Accuracy parameters for TCD were as follows: sensitivity = 96.7% (95% confidence interval [CI]= 80.9-99.8), specificity = 93.9% (95% CI = 89.9-96.4), PPV = 65.9% (95% CI = 50.0-79.1), NPV = 99.6% (95% CI = 97.2-1.0). Most false-positive patients (11 of 15 patients) had other significant intracranial large arteries lesions., Conclusions: The criteria have limited but acceptable sensitivity and specificity in detecting SICA stenoses. Abnormal findings of siphon carotid on TCD require further clarification.

Published
2010
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