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result(s) for
"Fung, Kenneth"
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A population-based phenome-wide association study of cardiac and aortic structure and function
2020
Differences in cardiac and aortic structure and function are associated with cardiovascular diseases and a wide range of other types of disease. Here we analyzed cardiovascular magnetic resonance images from a population-based study, the UK Biobank, using an automated machine-learning-based analysis pipeline. We report a comprehensive range of structural and functional phenotypes for the heart and aorta across 26,893 participants, and explore how these phenotypes vary according to sex, age and major cardiovascular risk factors. We extended this analysis with a phenome-wide association study, in which we tested for correlations of a wide range of non-imaging phenotypes of the participants with imaging phenotypes. We further explored the associations of imaging phenotypes with early-life factors, mental health and cognitive function using both observational analysis and Mendelian randomization. Our study illustrates how population-based cardiac and aortic imaging phenotypes can be used to better define cardiovascular disease risks as well as heart–brain health interactions, highlighting new opportunities for studying disease mechanisms and developing image-based biomarkers.
Using magnetic resonance images of the heart and aorta from 26,893 individuals in the UK Biobank, a phenome-wide association study associates cardiovascular imaging phenotypes with a wide range of demographic, lifestyle and clinical features.
Journal Article
Exploring the effects of web-based psychological capitals training on teachers’ PsyCap development, emotional stability, and support: Evidence from Chinese inclusive education
2024
Inclusive education for students with autism spectrum disorders (ASD) has increasingly received attention nationwide in China. Schools realize that teachers are under stress and lack the skills to handle daily interactions with these students. So far, few studies have directed efforts to provide a remedy for teachers to improve their daily work. This study aimed to design and implement a 2-hour web-based training on psychological capital (PsyCap) to protect their well-being and foster their supportive behavior for ASD students in the inclusive class. A total of 120 targeted teachers were invited to participate in the training and were randomly divided into control and treatment groups. Pre-, post-, and follow-up surveys were distributed before, after, and one week after the training. ANOVA results suggested that teachers showed a significant increase in their PsyCap scores after completing the training, although the training effect slightly decreased after one week. Moreover, higher levels of PsyCap showed a positive influence on teachers’ emotional stability and supportive behavior in class. The results highlighted the effectiveness of web-based PsyCap training in boosting teacher positivity, which enhances teacher support for students in inclusive education.
Journal Article
Automated cardiovascular magnetic resonance image analysis with fully convolutional networks
2018
Background
Cardiovascular resonance (CMR) imaging is a standard imaging modality for assessing cardiovascular diseases (CVDs), the leading cause of death globally. CMR enables accurate quantification of the cardiac chamber volume, ejection fraction and myocardial mass, providing information for diagnosis and monitoring of CVDs. However, for years, clinicians have been relying on manual approaches for CMR image analysis, which is time consuming and prone to subjective errors. It is a major clinical challenge to automatically derive quantitative and clinically relevant information from CMR images.
Methods
Deep neural networks have shown a great potential in image pattern recognition and segmentation for a variety of tasks. Here we demonstrate an automated analysis method for CMR images, which is based on a fully convolutional network (FCN). The network is trained and evaluated on a large-scale dataset from the UK Biobank, consisting of 4,875 subjects with 93,500 pixelwise annotated images. The performance of the method has been evaluated using a number of technical metrics, including the Dice metric, mean contour distance and Hausdorff distance, as well as clinically relevant measures, including left ventricle (LV) end-diastolic volume (LVEDV) and end-systolic volume (LVESV), LV mass (LVM); right ventricle (RV) end-diastolic volume (RVEDV) and end-systolic volume (RVESV).
Results
By combining FCN with a large-scale annotated dataset, the proposed automated method achieves a high performance in segmenting the LV and RV on short-axis CMR images and the left atrium (LA) and right atrium (RA) on long-axis CMR images. On a short-axis image test set of 600 subjects, it achieves an average Dice metric of 0.94 for the LV cavity, 0.88 for the LV myocardium and 0.90 for the RV cavity. The mean absolute difference between automated measurement and manual measurement is 6.1 mL for LVEDV, 5.3 mL for LVESV, 6.9 gram for LVM, 8.5 mL for RVEDV and 7.2 mL for RVESV. On long-axis image test sets, the average Dice metric is 0.93 for the LA cavity (2-chamber view), 0.95 for the LA cavity (4-chamber view) and 0.96 for the RA cavity (4-chamber view). The performance is comparable to human inter-observer variability.
Conclusions
We show that an automated method achieves a performance on par with human experts in analysing CMR images and deriving clinically relevant measures.
Journal Article
Reference ranges for cardiac structure and function using cardiovascular magnetic resonance (CMR) in Caucasians from the UK Biobank population cohort
2017
Cardiovascular magnetic resonance (CMR) is the gold standard method for the assessment of cardiac structure and function. Reference ranges permit differentiation between normal and pathological states. To date, this study is the largest to provide CMR specific reference ranges for left ventricular, right ventricular, left atrial and right atrial structure and function derived from truly healthy Caucasian adults aged 45–74.
Five thousand sixty-five UK Biobank participants underwent CMR using steady-state free precession imaging at 1.5 Tesla. Manual analysis was performed for all four cardiac chambers. Participants with non-Caucasian ethnicity, known cardiovascular disease and other conditions known to affect cardiac chamber size and function were excluded. Remaining participants formed the healthy reference cohort; reference ranges were calculated and were stratified by gender and age (45–54, 55–64, 65–74).
After applying exclusion criteria, 804 (16.2%) participants were available for analysis. Left ventricular (LV) volumes were larger in males compared to females for absolute and indexed values. With advancing age, LV volumes were mostly smaller in both sexes. LV ejection fraction was significantly greater in females compared to males (mean ± standard deviation [SD] of 61 ± 5% vs 58 ± 5%) and remained static with age for both genders. In older age groups, LV mass was lower in men, but remained virtually unchanged in women. LV mass was significantly higher in males compared to females (mean ± SD of 53 ± 9 g/m2 vs 42 ± 7 g/m2). Right ventricular (RV) volumes were significantly larger in males compared to females for absolute and indexed values and were smaller with advancing age. RV ejection fraction was higher with increasing age in females only. Left atrial (LA) maximal volume and stroke volume were significantly larger in males compared to females for absolute values but not for indexed values. LA ejection fraction was similar for both sexes. Right atrial (RA) maximal volume was significantly larger in males for both absolute and indexed values, while RA ejection fraction was significantly higher in females.
We describe age- and sex-specific reference ranges for the left ventricle, right ventricle and atria in the largest validated normal Caucasian population.
Journal Article
Chinese University Students’ Perspectives on Help-Seeking and Mental Health Counseling
2022
Psychological distress and mental illness have become increasingly pervasive among Chinese university students. However, many university students who need mental health treatment or psychological support do not actively seek help from professional counselors or service providers, which could lead to poor mental health outcomes. To promote help-seeking, we undertook a qualitative study to understand Chinese university students’ perspectives on help-seeking and mental health counseling. We conducted 13 focus group interviews with students in six universities in Jinan, China, and altogether 91 (62%) female students, and 56 (38%) male students participated in the study. Our results indicate that students’ misconception and distrust of on-campus counseling, stigma of mental illness, low mental health literacy, and hard-to-access mental health services are the major barriers that impede students help-seeking behaviors. Internal struggles and systematic and organizational barriers are identified to shed light on future work to promote mental health literacy among Chinese university students.
Journal Article
More than Mental Illness: Experiences of Associating with Stigma of Mental Illness for Chinese College Students
2022
From existing empirical research, we identified that Chinese college students commonly experience stigma surrounding mental illness and found some factors that support them in resisting the stigma and achieving psychological health. However, less research provides qualitative data involving individual experiences and insights on mental illness within this group of college students. This study, based on Linking Hearts (an internationally cooperative research-sharing project between China and Canada), was conducted in Shandong, Jinan, and aims to promote the mental health of college students by empowering interdisciplinary professionals and students. Through the research project, this study analyzed the materials from 24 focus groups, explored the understanding of mental illness and prevalence of mental illness stigma in Chinese colleges at the present time, administered a background questionnaire, and provided statistical support for some revealed themes. The final themes are as follows: mental illness is stereotyped as “severe, pathetic, and complicated”; the misconception of “visiting a psychological counselor is scary”; from public stigma to self-stigma; barriers deterring students from seeking help or accessing services; two sides of the same coin: peer support versus peer pressure.
Journal Article
Automated quality control in image segmentation: application to the UK Biobank cardiovascular magnetic resonance imaging study
2019
Background
The trend towards large-scale studies including population imaging poses new challenges in terms of quality control (QC). This is a particular issue when automatic processing tools such as image segmentation methods are employed to derive quantitative measures or biomarkers for further analyses. Manual inspection and visual QC of each segmentation result is not feasible at large scale. However, it is important to be able to automatically detect when a segmentation method fails in order to avoid inclusion of wrong measurements into subsequent analyses which could otherwise lead to incorrect conclusions.
Methods
To overcome this challenge, we explore an approach for predicting segmentation quality based on Reverse Classification Accuracy, which enables us to discriminate between successful and failed segmentations on a per-cases basis. We validate this approach on a new, large-scale manually-annotated set of 4800 cardiovascular magnetic resonance (CMR) scans. We then apply our method to a large cohort of 7250 CMR on which we have performed manual QC.
Results
We report results used for predicting segmentation quality metrics including Dice Similarity Coefficient (DSC) and surface-distance measures. As initial validation, we present data for 400 scans demonstrating 99% accuracy for classifying low and high quality segmentations using the predicted DSC scores. As further validation we show high correlation between real and predicted scores and 95% classification accuracy on 4800 scans for which manual segmentations were available. We mimic real-world application of the method on 7250 CMR where we show good agreement between predicted quality metrics and manual visual QC scores.
Conclusions
We show that Reverse classification accuracy has the potential for accurate and fully automatic segmentation QC on a per-case basis in the context of large-scale population imaging as in the UK Biobank Imaging Study.
Journal Article
Right ventricular shape and function: cardiovascular magnetic resonance reference morphology and biventricular risk factor morphometrics in UK Biobank
2019
Background
The associations between cardiovascular disease (CVD) risk factors and the biventricular geometry of the right ventricle (RV) and left ventricle (LV) have been difficult to assess, due to subtle and complex shape changes. We sought to quantify reference RV morphology as well as biventricular variations associated with common cardiovascular risk factors.
Methods
A biventricular shape atlas was automatically constructed using contours and landmarks from 4329 UK Biobank cardiovascular magnetic resonance (CMR) studies. A subdivision surface geometric mesh was customized to the contours using a diffeomorphic registration algorithm, with automatic correction of slice shifts due to differences in breath-hold position. A reference sub-cohort was identified consisting of 630 participants with no CVD risk factors. Morphometric scores were computed using linear regression to quantify shape variations associated with four risk factors (high cholesterol, high blood pressure, obesity and smoking) and three disease factors (diabetes, previous myocardial infarction and angina).
Results
The atlas construction led to an accurate representation of 3D shapes at end-diastole and end-systole, with acceptable fitting errors between surfaces and contours (average error less than 1.5 mm). Atlas shape features had stronger associations than traditional mass and volume measures for all factors (
p
< 0.005 for each). High blood pressure was associated with outward displacement of the LV free walls, but inward displacement of the RV free wall and thickening of the septum. Smoking was associated with a rounder RV with inward displacement of the RV free wall and increased relative wall thickness.
Conclusion
Morphometric relationships between biventricular shape and cardiovascular risk factors in a large cohort show complex interactions between RV and LV morphology. These can be quantified by z-scores, which can be used to study the morphological correlates of disease.
Journal Article
Cardiovascular magnetic resonance reference values of mitral and tricuspid annular dimensions: the UK Biobank cohort
2020
Background
Mitral valve (MV) and tricuspid valve (TV) apparatus geometry are essential to define mechanisms and etiologies of regurgitation and to inform surgical or transcatheter interventions. Given the increasing use of cardiovascular magnetic resonance (CMR) for the evaluation of valvular heart disease, we aimed to establish CMR-derived age- and sex-specific reference values for mitral annular (MA) and tricuspid annular (TA) dimensions and tethering indices derived from truly healthy Caucasian adults.
Methods
5065 consecutive UK Biobank participants underwent CMR using cine balanced steady-state free precession imaging at 1.5 T. Participants with non-Caucasian ethnicity, prevalent cardiovascular disease and other conditions known to affect cardiac chamber size and function were excluded. Absolute and indexed reference ranges for MA and TA diameters and tethering indices were stratified by gender and age (45–54, 55–64, 65–74 years).
Results
Overall, 721 (14.2%) truly healthy participants aged 45–74 years (54% women) formed the reference cohort. Absolute MA and TA diameters, MV tenting length and MV tenting area, were significantly larger in men. Mean ± standard deviation (SD) end-diastolic and end-systolic MA diameters in the 3-chamber view (anteroposterior diameter) were 2.9 ± 0.4 cm (1.5 ± 0.2 cm/m
2
) and 3.3 ± 0.4 cm (1.7 ± 0.2 cm/m
2
) in men, and 2.6 ± 0.4 cm (1.6 ± 0.2 cm/m
2
) and 3.0 ± 0.4 cm (1.8 ± 0.2 cm/m
2
) in women, respectively. Mean ± SD end-diastolic and end-systolic TA diameters in the 4-chamber view were 3.2 ± 0.5 cm (1.6 ± 0.3 cm/m
2
) and 3.2 ± 0.5 cm (1.7 ± 0.3 cm/m
2
) in men, and 2.9 ± 0.4 cm (1.7 ± 0.2 cm/m
2
) and 2.8 ± 0.4 cm (1.7 ± 0.3 cm/m
2
) in women, respectively. With advancing age, end-diastolic TA diameter became larger and posterior MV leaflet angle smaller in both sexes. Reproducibility of measurements was good to excellent with an inter-rater intraclass correlation coefficient (ICC) between 0.92 and 0.98 and an intra-rater ICC between 0.90 and 0.97.
Conclusions
We described age- and sex-specific reference ranges of MA and TA dimensions and tethering indices in the largest validated healthy Caucasian population. Reference ranges presented in this study may help to improve the distinction between normal and pathological states, prompting the identification of subjects that may benefit from advanced cardiac imaging for annular sizing and planning of valvular interventions.
Journal Article
HIV testing among heterosexual Black men in Toronto: What are the determinants?
by
Sano, Yujiro
,
Etowa, Egbe B.
,
Djiometio, Joseph Bertrand Nguemo
in
Adolescent
,
Adult
,
Attainment
2025
Objectives
African, Caribbean, and Black (ACB) men in Canada face a higher risk of HIV infection relative to other men. Despite this concern, these are nascent studies focused on the usage of HIV testing services among ACB men. To contribute to health policy in Canada, we seek to understand the prevalence and predictors of HIV testing among heterosexual ACB men living in Toronto.
Methods
We used a sample of 325 self-identified heterosexual Black men in Toronto, Ontario, who participated in the weSpeak study, which examined HIV vulnerability among ACB men. Guided by Andersen’s framework of health services utilization, we fitted negative log-log regression models to cross-sectional data of ACB men 16 years or older.
Results
The findings indicate that (1) ACB men with secondary or lower levels of educational attainment (OR = 0.57,
p
< 0.1) were less likely to have ever been tested for HIV compared to their counterparts with a university education or higher, (2) foreign-born men were more likely to have ever been tested for HIV than their Canadian-born counterparts (OR = 3.14,
p
< 0.01), and (3) ACB men who report multiple sexual partners were more likely to have ever been tested for HIV compared to colleagues with one sexual partner (OR = 2.76,
p
< 0.01).
Conclusion
Based on these findings, we recommend further research to understand the barriers to HIV testing among non-priority risk groups and the design of a more nuanced population-based approach to HIV testing that incorporates case management or various incentives.
Journal Article