Brain development is a continuous process which, from fetal period to adulthood, introduces changes in the brain both from a structural and functional point of view. The cerebral development in pediatric subjects is an issue of particular interest since substantial modifications in structures and tissues is observed together with the definition of cognitive functions. Magnetic resonance imaging enables to follow this process, by acquiring, in a non invasive way, high resolution images of the brain with several image constrasts (T1, T2, DTI, …). This PhD project has been focused on the implementation and application of advanced image processing methods that can be employed to qualitatively and quantitatively study the changes induced by maturation on brain structures and cerebral connectivity. The first part of the project has been dedicated to the implementation of a method to create brain atlases. The whole pediatric interval (0-17 years old) has been divided in six age ranges to describe the fundamental steps of normal brain development in children. Six brain atlases corresponding to these stages have been created. The availability of specific templates is very important to be used both as a normal reference in diagnostics and for group studies in research. In particular, an adaptive registration method based on Free-form Deformation was implemented. Compared to other approaches already published in literature, this method is characterized by a strong flexibility. In fact, it can be used with different image contrasts and at different age ranges by optimizing registration parameters depending on the image and population characteristics, such as the number of samples and their distance from the mean age of the range. The method has been demonstrated to be consistent, suggesting applications also for different purposes, for example it could be useful for longitudinal evaluation of progressive pathologies. The second part of the project concerned the study of functional magnetic resonance images in Resting State. The study was performed on preterm newborns subjects, in order to analyze the changes in functional connectivity during the very early brain developmental stages. The attention was focused on basic (ex. motor, visual) and high level (ex. cognitive, language) connectivity networks. The implemented method introduces the ability of performing correlation analysis at different resolution levels. The first resolution level is characterized by the study of each network, through image based Seed Correlation Analysis, both at single subject and at group level. The second resolution level consists in the study of the inter-network connections, performing correlation and regression analyses on BOLD signals extracted from brain areas belonging to the networks. This methodology might be employed also for other purposes, for example to provide a support during the diagnostic process of a pathology. Given the complexity of cerebral maturation process, in particular during pediatric period, the implementation of efficient and sophisticated methods for image processing is extremely important. This project fits in this context with the development of techniques for the integration of multiple types of data, which describe different aspects (anatomy, functionality) involved in brain development.

(2016). Studio dello sviluppo cerebrale in età pediatrica mediante tecniche avanzate di elaborazione di immagini a risonanza magnetica.. (Tesi di dottorato, Università degli Studi di Milano-Bicocca, 2016).

Studio dello sviluppo cerebrale in età pediatrica mediante tecniche avanzate di elaborazione di immagini a risonanza magnetica.

MARCHETTA, ELISA
2016

Abstract

Brain development is a continuous process which, from fetal period to adulthood, introduces changes in the brain both from a structural and functional point of view. The cerebral development in pediatric subjects is an issue of particular interest since substantial modifications in structures and tissues is observed together with the definition of cognitive functions. Magnetic resonance imaging enables to follow this process, by acquiring, in a non invasive way, high resolution images of the brain with several image constrasts (T1, T2, DTI, …). This PhD project has been focused on the implementation and application of advanced image processing methods that can be employed to qualitatively and quantitatively study the changes induced by maturation on brain structures and cerebral connectivity. The first part of the project has been dedicated to the implementation of a method to create brain atlases. The whole pediatric interval (0-17 years old) has been divided in six age ranges to describe the fundamental steps of normal brain development in children. Six brain atlases corresponding to these stages have been created. The availability of specific templates is very important to be used both as a normal reference in diagnostics and for group studies in research. In particular, an adaptive registration method based on Free-form Deformation was implemented. Compared to other approaches already published in literature, this method is characterized by a strong flexibility. In fact, it can be used with different image contrasts and at different age ranges by optimizing registration parameters depending on the image and population characteristics, such as the number of samples and their distance from the mean age of the range. The method has been demonstrated to be consistent, suggesting applications also for different purposes, for example it could be useful for longitudinal evaluation of progressive pathologies. The second part of the project concerned the study of functional magnetic resonance images in Resting State. The study was performed on preterm newborns subjects, in order to analyze the changes in functional connectivity during the very early brain developmental stages. The attention was focused on basic (ex. motor, visual) and high level (ex. cognitive, language) connectivity networks. The implemented method introduces the ability of performing correlation analysis at different resolution levels. The first resolution level is characterized by the study of each network, through image based Seed Correlation Analysis, both at single subject and at group level. The second resolution level consists in the study of the inter-network connections, performing correlation and regression analyses on BOLD signals extracted from brain areas belonging to the networks. This methodology might be employed also for other purposes, for example to provide a support during the diagnostic process of a pathology. Given the complexity of cerebral maturation process, in particular during pediatric period, the implementation of efficient and sophisticated methods for image processing is extremely important. This project fits in this context with the development of techniques for the integration of multiple types of data, which describe different aspects (anatomy, functionality) involved in brain development.
MORESCO, ROSA MARIA
SCIFO, PAOLA
Development; Magnetic Resonance Imaging; Template; RS-fMRI; Atlas
MED/50 - SCIENZE TECNICHE MEDICHE APPLICATE
Italian
4-mar-2016
TECNOLOGIE BIOMEDICHE - 20R
28
2014/2015
open
(2016). Studio dello sviluppo cerebrale in età pediatrica mediante tecniche avanzate di elaborazione di immagini a risonanza magnetica.. (Tesi di dottorato, Università degli Studi di Milano-Bicocca, 2016).
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/103406
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