Weili Lin, Ph.D. - US grants

In the past, jugular bulb venous oximetry has been used to provide a global overview of the dynamic relationship between brain oxygen delivery and demand in certain acute neurological disorders. However, the invasive nature of this method as well as the lack of regional specificity have limited the scope of its application in clinical practice. It is critical important to be able to accurately assess and quantify the relationships between oxygen supply and oxygen demand on a regional basis, so that the pathophysiology of acute stroke and related disorders can be investigated. In this proposal, we will test the general hypothesis that the oxygen saturation of venous blood within the brain parenchyma can be measured, in absolute terms, using advanced magnetic resonance imaging (MRI) techniques. Specifically, the MR signal intensity changes induced by the presence of deoxyhemoglobin within the cerebral vasculature will be measured using a novel gradient/spin echo sequence. High resolution maps of regional cerebral blood volume (rCBV) will also be measured using a three-dimensional steady state MRI method. Combining information from these two imaging sequences, the oxygen saturation of blood within the brain parenchyma can be estimated. We will first validate the proposed MRI methods by testing their ability to accurately predict the oxygen saturation of blood within the brain parenchyma of the rat under a wide variety of pathophysiologic conditions. The validation process will be carried out using well established physiologic manipulations that produce global changes in cerebral blood oxygen saturation and rCBV. These will include acute hemorrhagic hypotension, hemodilution, alterations of arterial carbon dioxide tension, and hypoxemia. These experimental paradigms lend themselves to direct comparison with the gold standard used throughout the project-the oxygen saturation of jugular venous blood samples. Finally, well characterized rat models of focal ischemic injury will be used to investigate the regional applicability of the proposed methods. The success of this proposal should provide the opportunity to non- invasively measure the oxygen saturation of blood within the brain parenchyma on a regional basis with high spatial resolution. This capability could introduce a widely available means for monitoring the dynamic pathophysiology of altered oxygen delivery, and the brain's response to certain therapeutic interventions.

DESCRIPTION (provided by applicant): The purpose of this application is to seek funding for purchasing the 3T Magnetic Resonance Imaging scanner, which is currently installed at the MR Research Center, Department of Radiology, UNC-Chapel Hill. This MR scanner is currently on loan to UNC through a research agreement between the Department of Radiology and Siemens Medical Systems, Inc for a span of 18 months. At the end of the 18 months, UNC-Chapel Hill will need to come up with funding to purchase this system, or this system will go back to Siemens. Unlike routinely utilized clinical scanners, this 3T system has a field strength that is as twice large as the clinical scanners. The increased field strength offers several important advantages over the clinical scanners. First, signal-to-noise ratio is anticipated to increase linearly with field strengths, making it possible to acquire very high-resolution anatomical images without affecting the SNR. This is likely to have profound implications for depicting small brain lesions as well as further facilitate tissue segmentation. Second, the sensitivity of revealing blood oxygen level dependent (BOLD) contrast is expected to increase. BOLD contrast is the underlying mechanism(s) that has been widely utilized for obtaining brain functional information, also known as fMRI. Recently, extensive efforts have been devoted to employ fMRl for the investigation of how the brain works as well as to probe how cognitive dysfunction occurs in patients with psychiatric disorders. The presence of the 3T scanner at UNC-Chapel Hill is likely to facilitate biomedical research on campus. Finally, one of the major strengths at UNC-Chapel Hill is animal research with the trans-genetically manipulated mouse models. In the past, an extensive amount of animals needed to be sacrificed for histological analysis. The presence of the 3T scanner will provide investigators a non-invasive tool to gain insight of the morphologic and/or patho-physiologic alterations associated with the trans-genetically manipulated animals without sacrificing them. Overall, the presence of the 3T MR scanner is likely to have profound implications for biomedical research at UNC-Chapel Hill.

sickle cell anemia; pediatrics; stroke; brain; functional magnetic resonance imaging; clinical research; human subject;

DESCRIPTION (provided by applicant): The purpose of this application is to seek funding for purchasing a 9.4T dedicated small animal magnetic resonance imaging (MRI) scanner. Recently, extensive efforts have been devoted to the development of non-invasive imaging methods for offering insights into the biological systems, including computed tomography (CT), positron emission tomography, single photon emission computed tomography (SPECT), and optical imaging. Among these modalities, MR is definitively the method of choice for providing superb soft tissue contrast, allowing for the investigation of subtle structural abnormalities. In addition, since MR is completely non-invasive, repeated measurements are readily available without worrying about radiation effects so that animals can be studied longitudinally. This is likely to substantially reduce the sample size while achieving a sufficient power. Although small animal imaging can be conducted independent of the field strength, the available signal-to-noise ratio (SNR) is proportional to the field strength as well as the spatial resolution. For example, in order to obtain high-resolution small animal images with a sufficiently high SNR, the required data acquisition time is about 36 times longer at 1.5T when compared to that at 9.4T, practically impossible for in vivo small animal imaging. Therefore, in order to obtain high quality and high-resolution small animal images, a 9.4T system is requested in this application. Such a system is likely to have profound implications for a wide variety of research projects and greatly enhance the research capability of the investigators at the University of North Carolina at Chapel Hill. The research projects listed in our application include cancer-related projects such as brain tumor and colorectal cancers, neurodegenerative, cardiovascular, cerebral vascular, and neurological diseases. All of these projects currently require sacrificing the animals and are unable to follow each animal longitudinally. Therefore, one of the immediate benefits of the 9.4T scanner is to offer insights into the biological system non-invasively, allowing longitudinal studies. In addition, through the utilization of MR spectroscopy as well as novel imaging methods, functional information is also readily available with the requested MR scanner. Therefore, there are not doubts that the requested 9.4T scanner will contribute substantially to the biological research at UNC-Chapel Hill. Finally, establishing a small animal imaging center is the highest priority at UNC-Chapel Hill. We have recently devised a CT and SPECT scanners for small animal imaging. The requested 9.4T MR scanner will definitively play a vital role and substantially strengthen our ability to establish a small animal-imaging center at UNC-Chapel Hill.

Small Animal Imaging Core The main goal of this small animal imaging (SAI) core is to support the proposed projects 1 - 4. Specifically, we will establish/develop the required imaging systems and methods so as to critically evaluate the nanoparticles developed in projects 1, 2 and 4 regarding their bio-distribution, half-life, effectiveness of providing imaging contrast, and potential ability to depict molecular events. In addition, imaging methods and image analysis tools focusing on monitoring lesion progression will also be developed. Furthermore, a direct comparison of the image quality between the proposed SAI computed tomography (CT) system in project 3 and a commercially available SAI CT will be conducted in order to provide strategies for the design of the proposed CT system. Currently, the small animal imaging facility at UNC houses a 3T magnetic resonance imaging (MRI) scanner, single photon emission computed tomography (SPECT) system, and in vivo optical imaging system. While these imaging systems are capable of providing high quality small animal images, additional developments specifically to serve the needs of the proposed projects 1 - 4 are needed. To this end, we will purchase and establish a high field SAI MR scanner to provide much higher spatial resolution images and improved sensitivity to iron oxide based contrast agents (proposed in projects 1, 2, and 4) in Aim 1a. A commercially available CT system will be purchased in Aim 1b to provide high quality and stable CT images for longitudinal studies. Aim 1c will further establish a web site that manages machine times and accesses to a dedicated PACS system. In contrast, Aim 2 will focus on developing/evaluating the nanoparticles developed in projects 1, 2, and 4 by utilizing MR, SPECT, and Ol (Aim 2a), direct comparing results from project 3 and that obtained from a commercially available CT system (Aim 2b), and developing multi-modality image analysis tools (Aim 2c).

The major goals of the Small Animal Imaging Core are to establish the needed infrastructure and develop image analysis tools for providing services to members of the UNC Lineberger Comprehensive Cancer Center. The Core will provide two main categories of services, including image acquisition and image analysis. The imaging modalities for the former service include magnetic resonance imaging/spectroscopy (MRI/MRS), single photon emission tomography (SPECT), optical imaging and computed tomography (CT). In particular, our research team has devised the SPECT and the first reported CT using a field emission carbon nanotube x-ray source. The ability to devise the imaging devices is likely to offer substantial flexibility to further improve the image quality in the near future. The latter service will provide image analysis tools such as lesion segmentation and co-registration for images acquired from the same animal but different modalities and/or different animals so that a group analysis can be conducted. The SAI core is led by Dr. Weili Lin who has extensive experience in MR imaging. The image analysis component will be led by Dr. Steve Aylward, who likewise has extensive experieince and funded research in image analysis. The Core adds value to the Center by offering non-invasive approaches to assess in vivo conditions and allow longitudinal studies, most likely substantially reducing the number of animals needed. In addition, the availability of multiple imaging modalities and the image analysis tools will provide powerful tools for the study of cancer mechanisms non-invasively.

Several lines of evidence derived from positron emission tomography (PET) studies suggest that measures of cerebral metabolic rate of oxygen utilization (CMRO2) provide an indication of brain tissue viability during cerebral ischemia. Although PET is a currently available technology to measure CMRO2, the need for an onsite cyclotron has limited its availability to only a few medical centers. Therefore, alternative approaches capable of providing similar physiological information as that of PET CMRO2 could have profound clinical implications. Towards this end, we have recently developed an MR imaging approach capable of measuring cerebral oxygen metabolic activity, which we have termed MR cerebral oxygen metabolic index (MR_COMI). Although physically different from PET CMRO2, preliminary results based on MR_COMI are encouraging, suggesting that this approach may indeed reveal similar physiological information as that of PET CMRO2. However, in order to determine if MR_COMI can delineate tissue viability during ischemia, a direct comparison between MR_COMI predicted tissue infarction and final tissue outcome under experimental conditions that are highly clinically relevant is of paramount importance. Therefore, the overall focus of this application is to first determine an MR_COMI threshold for irreversible injury and subsequently use this MR_COMI threshold to assess dynamic temporal and spatial evolution of MR_COMI defined lesions in response to cerebral ischemia (Aim 1) and second, empirically determine the predictive value of MR_COMI threshold, exploiting experimental conditions known to alter infarct volume (Aim 2). In addition, since this newly developed MR approach requires knowledge of regional cerebral hematocrit (Hct) which may change during cerebral ischemia, a parallel aim is proposed (Aim 3) to determine how cerebral ischemia induces alterations of cHct using small animal single photon emission computed tomography (SAI SPECT). Specifically, serial injections of two tracers: Tc-99m labeled red blood cells and Tc-99m labeled serum human albumin will be used to obtained SPECT images for the estimates of cHct. The success of the proposed studies will demonstrate that the newly developed MR approach is capable of delineate irreversibly injured from viable tissues under cerebral ischemia and may offer a tool for individualized treatment of acute stroke patients.

DESCRIPTION (provided by applicant): The ability to provide images with exquisite anatomical details has made magnetic resonance imaging (MRI) one of the most suitable imaging methods for the study of brain structure and brain development in pediatric subjects. However, MR is highly sensitive to motion artifacts. Without sedation, it will be a daunting task to obtain high quality brain images from the pediatric population. While sedation is commonly used for clinical imaging in pediatric patients, it is clearly not a choice for imaging children in research studies. Therefore, investigations of brain structure in normal children and in children with, or at high risk for neurodevelopmental disorders will require developing new MR methodologies. Recent advances on parallel imaging offer an ideal solution for imaging very young children without sedation by taking the unique features associated with the pediatric brains into consideration for the designs of imaging methods and coils. For example, it is conceivable to use a much smaller surface coil as that typically employed for adult imaging to maximize signal-to-noise (SNR) gains without worrying about the reduced coil sensitivity for deep brain structures and in conjunction with the parallel imaging to reduce data acquisition time. In addition, new image analysis tools specifically designed for the pediatric brains can further augment our ability to quantitatively measure normal brain developments. Therefore, the ultimate goal of this proposal is to develop dedicated imaging hardware and software for imaging very young children so as to allowing detailed characterizations of normal brain development. Specifically, this application consists of two major components: 1) technical developments for the required hardware (dedicated multi-channel phase array coils) and software (imaging sequences, reconstruction methods, and image analysis tools) and 2) the application of this novel methodology to longitudinally study normal brain development in an age range that is highly critical for functional and cognitive development, yet poorly understood currently (2wk - 2 years old). The proposed studies bring investigators with well-versed, yet complementary expertise, including investigators from Massachusetts General Hospitals who have extensive technical expertise for hardware developments of the dedicated rf coils and imaging expertise or parallel imaging methods and motion correction schemes as well as investigators at UNC-Chapel Hill who have extensive experience on imaging pediatric subjects, developing imaging methods, and developing novel image analysis tools. Together, it is highly likely that we will be able to recruit a large cohort of pediatric subjects for conducting a longitudinal imaging study, to reduce data acquisition time within 10 min, to obtain high quality MR images for quantitative characterizing normal brain developments.

[unreadable] DESCRIPTION (provided by applicant): A 3T Siemens Allegra head-only MR scanner fully dedicated to research is currently available at UNC-Chapel Hill (UNC-CH). This system has been widely utilized and is the sole human MR research scanner at UNC-CH. While most of the investigators have been happy with the capability and the image quality offered by this system, there are growing concerns regarding the limitations as well as the outlooks of this system. These concerns stem from the following reasons. First, while Siemens has continued to support our system, it is public information that Siemens will not put out additional efforts to further improve either the software or hardware of the Allegra system. Instead the main focus in Siemens is whole body MR scanners. As a result, given the rapid advances of MR technology, the capabilities of our current system will soon be out of date. Second, this system has a major hardware limitation when it comes to parallel imaging capability, one of the most major improvements in recent MR technology capable of shortening data acquisition time while preserving image quality. This limitation stems from the fact that this system can only equip with a maximum of 8 receivers, making it difficult to take full advantage of the parallel imaging technology. Finally, since this is a head-only scanner, it has been difficult expanding MR research activities beyond the neurological areas, nor does it allow imaging large animals. Therefore, in order to circumvent all of the above limitations, provide state-of-the-art MR imaging capability, and expand the MR imaging research program beyond neurologically related focuses at UNC-CH, funds are requested to replace our current Siemens 3T Allegra head-only scanner to a Siemens whole body TIM Trio 3T system. The currently existing Allegra will be traded in ($250k) so as to obtain a favorable price from Siemens ($2.05M). The major benefits offered by the requested Tim Trio 3T MR scanner for the currently funded NIH grants include: i) utilizing multi-channel (>8 receivers) capability to reduce total data acquisition time for pediatric studies; ii) minimizing geometric distortion when EPI images are acquired, ie diffusion tensor imaging (DTI) and functional MRI (fMRI) through the utilization of parallel imaging methods; and iii) further expanding MR research activities beyond neurologically related projects thanks to the whole body capabilities. Finally, an additional benefit is that our Institution has committed to purchase a position emission tomography (PET) insert that will be installed on the requested MR scanner upon successful funding of this application. This PET insert will not only further expand the imaging research program beyond MR but also allow the requested MR scanner to become an integrated MR-PET scanner, acquiring MR and PET images simultaneously. [unreadable] [unreadable] [unreadable]

Title: Animal Imaging Core Recent advances in small animal imaging have substanfially improved our ability to gain insights into disease progression without altering the biological systems. The small animal imaging facility at UNC currentiy houses nine major imaging equipments, including MRI (2), PET/CT (1), CT (1), SPECT (1), optical imaging (3), and ultrasound (1). In addition, skillful technical staff members to maintain and operate the imaging equipments and animal technicians to facilitate animal preparation for imaging and monitoring during imaging are available. Leveraging on these impressive resources, the small animal imaging (SAI) core aims to provide advanced imaging technology to facilitate the proposed projects. Specifically, two major imaging tasks will be carried out for the proposed projects, including to depict biodistribution of nanoparticles (Projects 1, 2, and 3) and to monitor and evaluate therapeutic efficacy of the proposed nanoparticles or treatment regirnens (Projects 2, 3, and 4) using imaging methods. To accomplish the former task, both PET and optical imaging methods will be developed to more efficiently and accurately provide biodistribution informafion. For the latter task, four imaging modalities, including optical, CT, PET, and MRI will be used to monitor therapeufic efficacy. Finally, while the imaging capability in the small animal imaging facility is already impressive, our insfitution has committed additional funds to further augment the imaging program at UNC, including the establishment of an on-site cyclotron facility and the associated radiochemistry lab and the development of imaging registrafion approaches for mulfimodality imaging using microCT, MRI, and PET (Projects 2, 3 and 4). Together, we believe that the available technical expertise and well established infrastructure in the small animal imaging facility will greatly facilitate the success ofthe proposed projects.

Small Animal Imaging Core Facility The goal of the Small Animal Imaging (SAI) core is to provide advanced animal imaging services, including imaging acquisition and image analysis tools that will facilitate cancer research at UNC and beyond. The imaging ability provided by the core allowed sophisticated monitoring of animal models, especially for studies focusing on cancer etiology and molecular therapeutics. The SAI core currently houses 10 imaging devices, including two 3T Siemens MR scanners, a 9.4T Bruker small animal MR scanner, a GE Explore animal PET/CT scanner, a UNC-designed high resolution SPECT scanner, a high resolution microCT for specimens (SCANCO), a high frequency ultrasound system (VisualSonics), and three IVIS optical imaging systems with capability for both bioluminescence and fluorescence imaging. Three additional imaging devices will be added to the SAI core in 2010: a GE SPECT/CT, a Fluorescence Molecular Tomography system, and a novel carbon nanotube-based CT. The SAI core currently supports 54 research projects. The SAI core requests $115,958 in CCSG funds, representing 12% its operating costs; 63% of the core's use is allocated to Cancer Center members. The increase in funding is requested to support the additional personnel and service contracts for new imaging equipment. For the next funding cycle, the SAI core proposes two major goals: expanding imaging, education and training services and developing multimodality imaging technology and analysis.

? DESCRIPTION (provided by applicant): Creating Normative Functional Brain Atlases during Infancy There is an increasing interest in exploring the mechanisms underlying early brain functional development using the resting state fMRI (rsfMRI) technique. Such explorations are promising for the detection of early functional connectivity biomarkers that are essential for the development of early diagnosis and intervention schemes for different pediatric neurological disorders such as cerebral palsy and epilepsy. However, given the dramatic functional evolution between infancy and adulthood, there are noteworthy difficulties for early developmental studies which include both the definition of infant-appropriate regions of interest (ROIs) and the accurate interpretation of the resulting functional connectivity patterns. Therefore, the establishment of infant-specific functional brain atlases represents an urgent mission for more rapid progress in the field. Our team has extensive experience in using rsfMRI to delineate normal brain functional connectivity development patterns during infancy and has accumulated a large sample of normal singleton infants (N=174) with longitudinal rsfMRI scans during the first two years of life. The availabilityof such a large-scale dataset provides us a unique opportunity to establish normative functional brain atlases during infancy. In fact, we have demonstrated the feasibility of such an endeavor and delineated the sub-regional functional segregation profile of the insula and thalamus during the first two years of life. Building on these previous experiences and leveraging the large-scale pre-existing data, the proposed study aims to establish a set of normative functional atlases for the first two years of life. Additionally, we will utilize existing behavioral data (i.e., Mullen Sores) measured at 1 and 2 years of age to evaluate the behavioral relevance and significance of the established functional atlases (Aim 1). Secondly, another equally important and unique dataset consisting of 120 dizygotic (DZ) and 88 monozygotic (MZ) twin infants scanned at the same age interval is also available and will be used to: i) independently validate the atlases established based on singleton infants; and ii) examine the associated genetic and environmental contributions to the functional atlases (Aim 2). Upon successful completion of the proposed project, we expect that a software package containing the established infant-specific normative functional brain atlases together with their behavioral correlation, genetic association, and environmental influences, will be made freely available to the early brain development research community to foster more rapid progress in the field (Aim 3). The approach is innovative because it will be the first to apply established functional connectivity clustering techniques to infant data and create normative functional brain atlases during infancy. The proposed research is significant because it is expected to provide the research community with an unprecedented set of references to expedite future explorations of the functional mechanisms underlying both normal and abnormal early brain development.

Project Summary This application is in response to the RFA-MH-16-160, entitled ?Lifespan Human Connectome Project (HCP): Baby Connectome?. Investigators at The University of North Carolina at Chapel Hill (UNC) and The University of Minnesota (UMN) will join forces to accomplish the goals outlined by this RFA. The team at UNC has over 10 years of experience in recruiting and imaging typically developing and at-risk children, scanning over 1000 children from birth to five years1-40. Well established infrastructure at the Biomedical Research Imaging Center (BRIC) at UNC and Center for Magnetic Resonance Research (CMRR) at UMN are in place to recruit and retain pediatric subjects and facilitate the coordination of pediatric imaging studies. Our past and ongoing studies for imaging children (birth ? five years of age) without sedation have achieved an overall success rate of 81% and attrition rate of 29.3%. Our track record demonstrates that we possess the critical and essential components to successfully conduct longitudinal pediatric imaging studies focusing on early brain development, a critically-important aspect of this RFA. Our ability to recruit, retain, and image non-sedated, typically developing children is further strengthened by our image analysis team, which has developed novel image analysis tools specifically for early brain development. The expertise at UNC is complementary to and strengthened by the expertise of the team at UMN. The CMRR at UMN has been one of the leading groups in the HCP project and has developed novel MR imaging approaches to dramatically shorten data acquisition time. Furthermore, the team at UMN has extensive experience in behavioral and cognitive studies of early child development. Together, our combined team is well positioned to accomplish the goals of this RFA. To this end, a total of 500 typically developing children between birth and five years of age will be recruited across two data collection sites in a sequential cohort, accelerated longitudinal study design. The participants are divided into two main groups, longitudinal (n=285) and cross-sectional (n=215) groups, respectively. This hybrid longitudinal and cross-sectional design enables detailed characterization of early brain development from both brain structural/functional using MRI and behavioral aspects using behavioral assessments. All of the acquired images and behavioral assessments will undergo extensive quality assurance and control processes to ensure that high quality data is obtained and transferred to the Central Connectome Facility at Washington University. In addition, we will integrate novel image analysis tools, developed by our team onto the existing HCP pipelines.

Project Summary Perivascular spaces (PVS), also known as the Virchow-Robin spaces, have been widely studied, which are defined as the pia-lined extensions of the subarachnoid space where subarachnoid CSF enters the brain. PVS surround penetrating arteries and continue along the outside of the penetrating arteries into white matter. Enlarged PVS are commonly observed in MR images in a number of neurological disorders. Normal PVS are typically not visible due to their small sizes, particularly in young adults. As a result, the physiological and pathophysiological significance of PVS remain elusive. Recently, several lines of evidence have suggested that PVS serve as part of the brain ?lymphatic? system through which interstitial solutes are cleared from the brain. Specifically, it has been demonstrated that arterial pulsation drives subarachnoid CSF flowing into the PVS and through which soluble proteins such as amyloid beta (A?) are cleared from the brain; dysfunction of PVS pathway thus may lead to enlarged PVS, an increased A? deposition, and subsequent neuronal dysfunction and loss, which clearly has profound implications in Alzheimer's diseases. While these recent studies have provided invaluable insights into the functions of PVS for cleaning interstitial solutes, invasive approaches such as two-photon microscopy or infusion of fluorescent and radio- labeled tracers were employed, which are not applicable to humans. Therefore, there are increasing needs of developing non-invasive approaches capable of revealing the PVS morphological (diameters, lengths and so on) and hemodynamic (velocity and arterial pulsation) features so as to allow direct assessments of the functional status of PVS. We have recently demonstrated that both the morphological and hemodynamic features of PVS in healthy young adults can be assessed using 7T. While our preliminary results demonstrate the feasibility of imaging PVS, in this application we propose to take steps further by developing imaging approaches capable of separately evaluating the morphological features of CSF and penetrating vessels (Aim 1). The ability of separately evaluating these two compartments in PVS will reveal if the CSF, penetrating vessels or both are altered in diseased populations. Furthermore, the flow velocity and arterial pulsatility of the penetrating arterioles in PVS will be measured in Aim 2 which could, potentially, enable the evaluation of how interstitial solutes are cleared from the brain. Finally, how these parameters are modified with aging will also be evaluated in Aims 1 and 2.

? DESCRIPTION (provided by applicant): The first two years of life is the most dynamic and perhaps the most critical phase of postnatal brain development. The ability to accurately characterize structure changes is very critical for the exploration of early brain development and early detection of neurodevelopmental disorder in imaging-based studies, which highly relies on image segmentation and registration techniques. However, either infant image segmentation or registration, if deployed independently, encounters more challenges than adult brains due to the dramatic appearance change and rapid brain development. Fortunately, image segmentation and registration can assist each other to overcome the difficulties by using the growth trajectories (temporal correspondences) learned from a large amount of complete longitudinal data (at 2 weeks, 3 months, 6 months, 9 months, 1 year and 2 years of age) with multi-modality images (T1, T2, and DTI) collected in UNC-CH. Specifically, we will develop a joint segmentation and registration framework to determine the tissue type for each image point and simultaneously find the deformation pathway between any two infant brain images with significant age gap (Aim 1). Preliminary results demonstrate significant benefits of this approach. After comprehensively evaluating its performance on a large number of infant data, we will package our joint segmentation and registration approach into a software package and release it freely to the community (Aim 2), as we have done with our other software packages that have been downloaded for more than 10,000 times. Considering the importance of image segmentation and registration in computational anatomy area, this cutting-edge technique will be also very useful for many ongoing early brain development studies.

Abstract In the first years of life, when the brain is rapidly developing, children are disproportionately exposed to xenobiotics, including phthalates. However, the immaturity of the blood brain barrier cerebrovasculature and xenobiotic metabolism and excretion pathways render the infant brain more vulnerable to toxic compounds. Despite growing evidence of associations of prenatal phthalate exposures with diverse aspects of neurobehavioral development, few studies have assessed the role of early life exposure to phthalates on neurodevelopment. Furthermore, the findings on prenatal exposure have been paradoxical, suggesting that phthalate exposure accelerates the maturity of functional networks in infancy but is maladaptive in later life. Our objective is to examine the extent to which phthalate exposures change structural and functional brain development at a critical window of vulnerability (from birth to age 5), and to reconcile the paradoxical findings by tracking a variety of social, behavioral and developmental outcomes through longitudinal evaluation. We propose to leverage the University of North Carolina Baby Connectome Project (BCP), the goal of which is to map normative brain development in early life using serial structural (sMRI) and resting-state functional (rsfMRI) magnetic resonance imaging paired with age-appropriate developmental assessments. In a pilot study, we found that higher early life exposure to monobenzyl phthalate (MBzP) is associated with larger cortical gray matter volumes in regions of the frontal cortex that direct language processing and executive function, as well as dysregulated functional connectivity in the primary visual, default mode, and sensorimotor networks. While this pilot established a strong scientific premise for further study, it had a limited sample size and only measured a subset of relevant phthalates. To provide a comprehensive and unbiased understanding of the phthalate and exposomic landscape in early life, we propose to extend our analysis to 19 phthalates and phthalate replacements and to evaluate the unbiased, untargeted exposome. For a more in-depth developmental perspective, we also propose to examine the longitudinal relationship between early life toxicant exposures and sMRI, rsfMRIs and developmental inventories. We plan to increase enrollment by 50 children, resulting in a final sample size of approximately 250 children contributing approximately 540 scans. Our group has pioneered the quantitative characterization of spatiotemporal brain development in early infancy and includes a unique assemblage of expertise in environmental epidemiology, infant brain imaging, early brain development, toxicology, biostatistics, and child psychiatry that will ensure successful completion of this work. This study has important public health significance because phthalate exposures are ubiquitous, largely unregulated in the US, and more extensive and impactful to infants than to adults. Imaging biomarkers will provide crucial information on the mechanism of phthalate neurotoxicity that will guide regulatory action to protect children from maladaptive developmental outcomes.

PROJECT SUMMARY/ABSTRACT Brain development occurs at a rapid pace prenatally and throughout childhood, impacted by dynamic genetic and environmental influences. Studies using advanced neuroimaging have provided significant insights into brain development but have been limited by small sample size, especially for high-risk populations. Substance- exposed infants are at particularly high risk for adverse outcomes; however, findings are inconsistent, making it difficult to disentangle prenatal exposure effects from other adverse influences. The objectives of our HEALthy Brain and Child Development (HBCD) Prenatal Experiences and Longitudinal Development (PRELUDE) consortium are to characterize typical trajectories of brain development from birth through childhood, measuring the influence of key biologic and environmental factors and their interactions on child social, cognitive, and emotional development. We will assess how children prenatally exposed to opioids and other substances, as well as environmental adversity, differ in those brain trajectories and outcomes. Our consortium consists of six centers (Arkansas Children?s Research Institute, Case Western Reserve University, Cincinnati Children?s Hospital, Children?s National Medical Center, University of North Carolina at Chapel Hill, and Vanderbilt University) which have collaborated previously and have complementary expertise in neuroimaging, neurophysiology, longitudinal clinical research, child development, substance exposure and addiction, ethical/legal issues, and clinical care of high-risk infants/children. The PRELUDE consortium will recruit 680 pregnant women with substance use, 680 at-risk pregnant women without substance use, and 1360 comparison pregnant women representative of the general population to contribute to the overall HBCD study. We will work closely with the other sites, the HBCD Consortium Administrative Core, and the HBCD Data Coordinating Center to develop a comprehensive study protocol and ensure compliance of study workflow and data transfer. Our consortium has an optimized research protocol and 4 specific aims: 1) Employ ethical and evidence-based best practices to enroll and retain a diverse cohort of pregnant women into a longitudinal study of infant/child brain development, oversampling mothers from high-risk backgrounds and those using substances during pregnancy; 2) Engage a comprehensive array of maternal- and child-oriented community stakeholders to identify community concerns and priorities regarding this research, minimize risks, and promote long-term engagement of the recruited child-mother dyads; 3) Collect rich data to examine how maternal health context and broader environmental factors may affect the maternal-fetal dyad and neurodevelopment of children; 4) Capture key developmental windows during which maternal and environmental factors may interact with brain and behavioral development of children. The insights from these data will provide greater understanding of factors affecting early childhood brain development, allowing targeted interventions and improved outcomes for mother-child dyads.