Computerized Analysis of Magnetic Resonance Images to Study Cerebral Anatomy in Developing Neonates

The study of cerebral anatomy in developing neonates is of great importance for the understanding of brain development during the early period of life. This dissertation therefore focuses on three challenges in the modelling of cerebral anatomy in neonates during brain development. The methods that have been developed all use Magnetic Resonance Images (MRI) as source data. To facilitate study of vascular development in the neonatal period, a set of image analysis algorithms are developed to automatically extract and model cerebral vessel trees. The whole process consists of cerebral vessel tracking from automatically placed seed points, vessel tree generation, and vasculature registration and matching. These algorithms have been tested on clinical Time-of- Flight (TOF) MR angiographic datasets. To facilitate study of the neonatal cortex a complete cerebral cortex segmentation and reconstruction pipeline has been developed. Segmentation of the neonatal cortex is not effectively done by existing algorithms designed for the adult brain because the contrast between grey and white matter is reversed. This causes pixels containing tissue mixtures to be incorrectly labelled by conventional methods. The neonatal cortical segmentation method that has been developed is based on a novel expectation-maximization (EM) method with explicit correction for mislabelled partial volume voxels. Based on the resulting cortical segmentation, an implicit surface evolution technique is adopted for the reconstruction of the cortex in neonates. The performance of the method is investigated by performing a detailed landmark study. To facilitate study of cortical development, a cortical surface registration algorithm for aligning the cortical surface is developed. The method first inflates extracted cortical surfaces and then performs a non-rigid surface registration using free-form deformations (FFDs) to remove residual alignment. Validation experiments using data labelled by an expert observer demonstrate that the method can capture local changes and follow the growth of specific sulcus

How Fine Particulate Matter Modifies Preterm Birth Risks in Korea

Despite the increasing interest in preterm birth risk associated with maternal exposure to the current level of fine particulate matter (PM2.5) in Korea, there is little information on differences in PM2.5 exposure and its impact on preterm birth. This study was designed to examine the effects of Korea\u27s air quality on preterm birth, including the possibility of moderation and mediation. This work was also designed to investigate manipulable factors for PM2.5 exposure. The theoretical framework of this quantitative and observational study included the social ecological theory and systems theory. The conceptual framework of this partially ecologic and retrospective cohort study included the social ecological model and Rothman\u27s sufficient component cause model. Data of 19,371 Korean women who gave birth in 2015 were analyzed by logistic regression and multiple regression, including testing for moderation and mediation. An increase in PM2.5 exposure by 10 μg/m3 in the 3rd week before childbirth increased the likelihood of preterm birth by 6.52 times. Moderation and mediation by PM2.5 did not exist between sociodemographic factors and gestational age but existed between socioeconomic and energy policy factors and gestational age. The most influential factor for PM2.5 exposure was unemployment rate at the organizational level. These results show the need for socioeconomic interventions to reduce PM2.5 exposure more effectively. These �ndings indicate that prenatal care should be addressed with a socioeconomic- and energy-policy-sensitive approach to lower preterm birth due to severe air pollution in Korea. This study has the potential to change people\u27s perceptions of threats from PM2.5 exposure, which could lead to behavior changes

i-VOTING USING TRIP

ABSTRACT: Data imputation aims at filling in missing attribute values in databases

Mind the gap:Socioeconomic health inequalities in early life

Health differences between most and least advantaged become apparent right from the earliest stages of life, manifesting as adverse birth outcomes. The overarching aim of this thesis was to delve into the complex relationship between socioeconomic status (SES) and early-life health, with a particular focus on the role played by neighbourhood-level socioeconomic conditions

Mind the gap:Socioeconomic health inequalities in early life

Health differences between most and least advantaged become apparent right from the earliest stages of life, manifesting as adverse birth outcomes. The overarching aim of this thesis was to delve into the complex relationship between socioeconomic status (SES) and early-life health, with a particular focus on the role played by neighbourhood-level socioeconomic conditions

Finding new answers in old trials with data linkage. A novel method to assess whether nutrient intake in infancy affects long-term cognition

Background Due to high attrition in randomised controlled trials (RCTs), cognitive effects of infant formula modifications remain uncertain. The aim of this thesis was to test a new method to minimise attrition and, through doing so, to compare differences in academic performance between children previously randomised to either nutritionally modified or standard infant formula. Methods Nine dormant infant formula RCTs conducted in England (1982-2001) were available for linkage to the National Pupil Database. Linkage was based on legal exemption from the need for participant consent. A trusted third party provided de-identified data for up to four candidate pupil matches per participant and agreement-metrics for all shared linkage variables. I completed the linkage of de-identified data, using auxiliary RCT variables and probabilistic methods. Six RCTs (n=1,563) were eligible for analysis, and a further three RCTs were used to assess linkage success and improve multiple imputation of missing data. Participant academic performance was measured using exam grades, with the primary outcome being General Certificate of Secondary Education (GCSE) Maths grades at age 16 years. Modified formula and standard formula groups were compared on an intention-to-treat basis, stratified by trial. Results Within the six trials eligible for analysis, primary outcome data was available for 86% of all participants. Available outcome data was substantially higher than the average of 22% above age 2 years in previous consent-based cognitive follow-ups of the trials. There was no evidence of benefit for GCSE Maths performance for any type of modified formula. Secondary academic outcomes provided weak evidence of harm for one of the formula modifications. Conclusions Unconsented linkage of dormant trials to administrative education data is feasible and leads to higher follow-up rates compared to traditional consented follow-up methods. None of the investigated nutritionally modified formula interventions improved academic performance

The Application of Simulation to Quantifying the Influence of Bias in Perinatal Epidemiology

Perinatal aetiological associations derived from observational data are susceptible to various types of bias. This thesis demonstrated the application of simulation methodologies to quantify the influence of bias in perinatal epidemiology through a series of simulation studies which quantified the magnitude and direction of bias mechanisms. A framework to guide epidemiologists in the development, implementation and reporting of simulation studies to quantify bias was developed. Simulation is a potent tool to the quantification of bias

Towards an Unsupervised Bayesian Network Pipeline for Explainable Prediction, Decision Making and Discovery

An unsupervised learning pipeline for discrete Bayesian networks is proposed to facilitate prediction, decision making, discovery of patterns, and transparency in challenging real-world AI applications, and contend with data limitations. We explore methods for discretizing data, and notably apply the pipeline to prediction and prevention of preterm birth

Associations Between Climate, Latitude, Fertility and the Decline of the US Sex Ratio at Birth

The US sex ratio at birth (SRB) has declined since 1970, while ambient temperatures have been increasing. This study examines the temporal and spatial variation of the US SRB from 1979–2002 in association with fertility rates and climate variables. Approximately 62.8 million birth records from the National Center for Health Statistics were linked to monthly climate division data and county level socioeconomic variables to evaluate the association of SRB and environmental conditions at or near the time of conception. Seasonal variation in US SRB is detectable in time series analysis, and is somewhat in phase with variation in fertility. Logistic regression analysis shows that temperature in the month before conception is significantly positively correlated with the likelihood of a male birth when birth order, maternal age, maternal education, plurality, gestation length, race, and Hispanic origin are controlled. This association was significant in models that include all births from 1979–1988, non-Hispanic white births from 1979–1988, and all births in US large counties from 1979–2002. Geographic nonstationarity of US SRB was found in smoothed rate climate division maps for 1979–1988, with higher SRB in latitudes below 40 degrees N, especially in the southeastern US. However, both the overall rates of summer conception and the likelihood of summer male conception are reduced in lower latitudes relative to higher ones. A logistic regression model was also fit using only non-Hispanic births from US large counties from 1989–2002. In addition to a significant positive association of sex ratio and temperature in the month before conception, deviation from normal monthly temperature during the month of conception, compared to the 1971–2000 baseline temperature, is significantly associated with sex ratio variation. In this population, fewer males were conceived when temperature extremes were significantly above normal; more males were conceived when temperatures were significantly below normal. In both high and low latitude zones over this period, the peak of male conceptions shifted to earlier in the year. Variation in SRB is potentially a sentinel health event and this research suggests that the association between temperature and SRB should be integral to any study of SRB variation across large geographic areas or long time periods

Adverse Birth Outcomes in U.S.- and Foreign-Born Black Women: A Conceptual and Empirical Analysis.

Background: This dissertation explored racism and birth outcomes in U.S.- and foreign-born Black women and examined the degree to which commonly-measured risk factors could explain why Black Caribbean immigrants have lower rates of preterm birth than African Americans. It included: a review of how race- and nativity-based disparities have been conceptualized in perinatal health research; an examination of preterm birth predictors among Caribbean- and U.S.-born Black women; and an assessment of preterm birth risk by maternal age and immigrants’ duration of U.S. residence. Methods: Systematic literature review coupled with logistic regression analyses utilizing birth records from New York City (2000-2010) and the U.S. Virgin Islands (2000-2004). Results: The review produced no generalizable evidence for suggested causes of racial or Black ethnic disparities in birth outcomes. However, there is modest support that racism is associated with adverse birth outcomes, and the perinatal health advantage for Black immigrants is ascribed to selective migration and culturally-linked factors, although the evidence is sparse. In this study, Caribbean-born immigrants in New York City sustained lower odds of preterm birth relative to U.S.-born Blacks (OR = 0.85, 95% CI: 0.76, 0.94) and Caribbean-born residents in the Virgin Islands (OR = 0.54, 95% CI: 0.34, 0.89) despite adjustment for demographic, behavioral, and medical risk factors. Age and education were most influential in explaining the preterm birth advantage for Black Caribbean immigrants, and there was modest support for selective migration. However, the risks of preterm birth with advancing maternal age were similar between Caribbean-born immigrants (OR = 1.13, 95% CI: 1.10, 1.15) and U.S.-born mothers (OR = 1.15, 95% CI: 1.13, 1.17) in New York City. Further, the odds of preterm birth among Caribbean immigrants increased 7% for every 5 years of U.S. residence (OR = 1.07, 95% CI: 1.04, 1.11). Conclusions: The “healthy migrant” effect for Black Caribbean immigrants is conditional on national origin and length of time in the U.S. The worsening of immigrant mothers’ preterm birth risks with increased duration of U.S. residence warrants additional research into contextual factors, including racism, to yield greater insight into perinatal health disparities among native and foreign-born Black women.PhDHealth Behavior and Health EducationUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/111549/1/dccarty_1.pd