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Mapping region-specific longitudinal cortical surface expansion from birth to 2 years of age”. Cereb. Cortex
"... The human cerebral cortex develops rapidly and dynamically in the first 2 years of life. It has been shown that cortical surface expansion from term infant to adult is highly nonuniform in a cross-sectional study. However, little is known about the longitudinal cortical surface expansion during earl ..."
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The human cerebral cortex develops rapidly and dynamically in the first 2 years of life. It has been shown that cortical surface expansion from term infant to adult is highly nonuniform in a cross-sectional study. However, little is known about the longitudinal cortical surface expansion during early postnatal stages. In this article, we generate the first longitudinal surface-based atlases of human cortical struc-tures at 0, 1, and 2 years of age from 73 healthy subjects. On the basis of the surface-based atlases, we study the longitudinal cortical surface expansion in the first 2 years of life and find that cortical surface expansion is age related and region specific. In the first year, cortical surface expands dramatically, with an average expansion of 1.80 times. In particular, regions of superior and medial temporal, superior parietal, medial orbitofrontal, lateral anterior prefrontal, occi-pital cortices, and postcentral gyrus expand relatively larger than other regions. In the second year, cortical surface still expands sub-stantially, with an average expansion of 1.20 times. In particular, regions of superior and middle frontal, orbitofrontal, inferior temporal, inferior parietal, and superior parietal cortices expand relatively larger than other regions. These region-specific patterns of cortical surface expansion are related to cognitive and functional development at these stages.
4D Segmentation of Brain MR Images with Constrained Cortical Thickness Variation
, 2012
"... Segmentation of brain MR images plays an important role in longitudinal investigation of developmental, aging, disease progression changes in the cerebral cortex. However, most existing brain segmentation methods consider multiple timepoint images individually and thus cannot achieve longitudinal co ..."
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Segmentation of brain MR images plays an important role in longitudinal investigation of developmental, aging, disease progression changes in the cerebral cortex. However, most existing brain segmentation methods consider multiple timepoint images individually and thus cannot achieve longitudinal consistency. For example, cortical thickness measured from the segmented image will contain unnecessary temporal variations, which will affect the time related change pattern and eventually reduce the statistical power of analysis. In this paper, we propose a 4D segmentation framework for the adult brain MR images with the constraint of cortical thickness variations. Specifically, we utilize local intensity information to address the intensity inhomogeneity, spatial cortical thickness constraint to maintain the cortical thickness being within a reasonable range, and temporal cortical thickness variation constraint in neighboring time-points to suppress the artificial variations. The proposed method has been tested on BLSA dataset and ADNI dataset with promising results. Both qualitative and quantitative experimental results demonstrate the advantage of the proposed method, in comparison to
Anatomical Correlates of Cognitive Functions in Early Parkinson’s Disease Patients
, 2013
"... Background: Cognitive deficits may occur early in Parkinson’s disease (PD) but the extent of cortical involvement associated with cognitive dysfunction needs additional investigations. The aim of our study is to identify the anatomical pattern of cortical thickness alterations in patients with early ..."
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Background: Cognitive deficits may occur early in Parkinson’s disease (PD) but the extent of cortical involvement associated with cognitive dysfunction needs additional investigations. The aim of our study is to identify the anatomical pattern of cortical thickness alterations in patients with early stage PD and its relationship with cognitive disability. Methods: We recruited 29 PD patients and 21 healthy controls. All PD patients performed an extensive neuropsychological examination and 14 were diagnosed with mild cognitive impairment (PD-MCI). Surface-based cortical thickness analysis was applied to investigate the topographical distribution of cortical and subcortical alterations in early PD compared with controls and to assess the relationship between cognition and regional cortical changes in PD-MCI. Results: Overall PD patients showed focal cortical (occipital-parietal areas, orbito-frontal and olfactory areas) and subcortical thinning when compared with controls. PD-MCI showed a wide spectrum of cognitive deficits and related significant regional thickening in the right parietal-frontal as well as in the left temporal-occipital areas. Conclusion: Our results confirm the presence of changes in grey matter thickness at relatively early PD stage and support previous studies showing thinning and atrophy in the neocortex and subcortical regions. Relative cortical thickening in PD-MCI may instead express compensatory neuroplasticity. Brain reserve mechanisms might first modulate cognitive decline
NeuroImage 76 (2013) 216–224 Contents lists available at SciVerse ScienceDirect
"... journal homepage: www.elsevier.com/locate/ynimg Development of cortical anatomical properties from early childhood to ..."
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journal homepage: www.elsevier.com/locate/ynimg Development of cortical anatomical properties from early childhood to
Cerebral Cortex doi:10.1093/cercor/bhs413 Cerebral Cortex Advance Access published January 10, 2013 Mapping Longitudinal Hemispheric Structural Asymmetries of the Human Cerebral Cortex From Birth to 2 Years of Age
"... Mapping cortical hemispheric asymmetries in infants would increase our understanding of the origins and developmental trajectories of hemispheric asymmetries. We analyze longitudinal cortical hemispheric asymmetries in 73 healthy subjects at birth, 1, and 2 years of age using surface-based morphomet ..."
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Mapping cortical hemispheric asymmetries in infants would increase our understanding of the origins and developmental trajectories of hemispheric asymmetries. We analyze longitudinal cortical hemispheric asymmetries in 73 healthy subjects at birth, 1, and 2 years of age using surface-based morphometry of magnetic resonance images with a specific focus on the vertex position, sulcal depth, mean curvature, and local surface area. Prominent cortical asymmetries are found around the peri-Sylvian region and superior temporal sulcus (STS) at birth that evolve modestly from birth to 2 years of age. Sexual dimorphisms of cortical asymmetries are present at birth, with males having the larger magnitudes and sizes of the clusters of asymmetries than females that persist from birth to 2 years of age. The left supramarginal gyrus (SMG) is significantly posterior to the right SMG, and the maximum position difference increases from 10.2 mm for males (6.9 mm for females) at birth to 12.0 mm for males (8.4 mm for females) by 2 years of age. The right STS and parieto-occipital sulcus are significantly larger and deeper than those in the left hemisphere, and the left planum temporale is significantly larger and deeper than that in the right hemisphere at all 3 ages. Our results indicate that early hemispheric structural asymmetries are inherent and gender related.
MEASURING LONGITUDINALLY DYNAMIC CORTEX DEVELOPMENT IN INFANTS BY RECONSTRUCTION OF CONSISTENT CORTICAL SURFACES
"... Quantitative measurement of dynamic cortex development during early postnatal stages is of great importance to understand early cortical structural and functional development. Conventional methods usually independently reconstruct cortical surfaces of longitudinal images from the same infant, which ..."
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Quantitative measurement of dynamic cortex development during early postnatal stages is of great importance to understand early cortical structural and functional development. Conventional methods usually independently reconstruct cortical surfaces of longitudinal images from the same infant, which often generates longitudinallyinconsistent cortical surfaces and leads to inconsistence in cortex development measurement. This paper aims to address this problem by presenting a method to reconstruct consistent cortical surfaces from longitudinal brain MR images in the first-year infants for accurate and consistent measurement of dynamic cortex development. Specifically, longitudinal development of the inner cortical surface is first modeled by a deformable sheet with elasto-plasticity property to establish longitudinally smooth correspondences of inner cortical surfaces. Then, the modeled longitudinal inner cortical surfaces are jointly deformed to locate inner and outer cortical surfaces with a spatial-temporal deformable surface. The method has been applied on 10 infants, each with 5 or 6 scans acquired at every 3 months from birth. Experimental results show that our method can accurately and consistently reconstruct dynamic cortical surfaces from longitudinal infant images, with the average surface distance as low as 0.2mm. By using our method, we can quantitatively characterize longitudinally dynamic cortical thickness development in the first-year infants. Index Terms—infant longitudinal cortical surfaces, infant cortical thickness development 1.
Consistent 4D Brain Extraction of Serial Brain MR Images
"... Accurate and consistent skull stripping of serial brain MR images is of great importance in longitudinal studies that aim to detect subtle brain morphological changes. To avoid inconsistency and the potential bias introduced by independently performing skull-stripping for each time-point image, we p ..."
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Accurate and consistent skull stripping of serial brain MR images is of great importance in longitudinal studies that aim to detect subtle brain morphological changes. To avoid inconsistency and the potential bias introduced by independently performing skull-stripping for each time-point image, we propose an effective method that is capable of skull-stripping serial brain MR images simultaneously. Specifically, all serial images of the same subject are first affine aligned in a groupwise manner to a common space to avoid any potential bias introduced by asymmetric transforms. A brain probability map, which encapsulates prior information gathered from a population of real brain MR images, is then warped to the aligned serial images for guiding skull-stripping via a deformable surface method. In particular, the same initial surface meshes representing the initial brain surfaces are first placed on all aligned serial images, and then all these surface meshes are simultaneously evolved to the respective target brain boundaries, driven by the intensity-based force, the force from the probability map, as well as the force from the spatial and temporal smoothness. Especially, imposing the temporal smoothness helps achieve longitudinally consistent results. Evaluations on 20 subjects, each with 4 time points, from the ADNI database indicate that our method gives more accurate and consistent result compared with 3D skull-stripping method. To better show the advantages of our 4D brain extraction method over the 3D method, we compute the Dice ratio in a ring area (±5mm) surrounding the ground-truth brain boundary, and our 4D method achieves around 3 % improvement over the 3D method. In addition, our 4D method also gives smaller mean and maximal surfaceto-surface distance measurements, with reduced variances.
Cerebral Cortex doi:10.1093/cercor/bhs265 Cerebral Cortex Advance Access published August 23, 2012 Mapping Region-Specific Longitudinal Cortical Surface Expansion from Birth to 2 Years of Age
"... The human cerebral cortex develops rapidly and dynamically in the first 2 years of life. It has been shown that cortical surface expansion from term infant to adult is highly nonuniform in a cross-sectional study. However, little is known about the longitudinal cortical surface expansion during earl ..."
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The human cerebral cortex develops rapidly and dynamically in the first 2 years of life. It has been shown that cortical surface expansion from term infant to adult is highly nonuniform in a cross-sectional study. However, little is known about the longitudinal cortical surface expansion during early postnatal stages. In this article, we generate the first longitudinal surface-based atlases of human cortical structures at 0, 1, and 2 years of age from 73 healthy subjects. On the basis of the surface-based atlases, we study the longitudinal cortical surface expansion in the first 2 years of life and find that cortical surface expansion is age related and region specific. In the first year, cortical surface expands dramatically, with an average expansion of 1.80 times. In particular, regions of superior and medial temporal, superior parietal, medial orbitofrontal, lateral anterior prefrontal, occipital cortices, and postcentral gyrus expand relatively larger than other regions. In the second year, cortical surface still expands substantially, with an average expansion of 1.20 times. In particular, regions of superior and middle frontal, orbitofrontal, inferior temporal, inferior parietal, and superior parietal cortices expand relatively larger than other regions. These region-specific patterns of cortical surface expansion are related to cognitive and functional development at these stages.
