Correction of spatial distortion in magnetic resonance imaging

Detalhes bibliográficos
Autor(a) principal: Mendes, Pedro Mota
Data de Publicação: 2011
Tipo de documento: Dissertação
Idioma: eng
Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
Texto Completo: http://hdl.handle.net/10362/6333
Resumo: Dissertation to Obtain the Degree of Master in Biomedical Engineering
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spelling Correction of spatial distortion in magnetic resonance imagingImage qualityImage processingMagnetic resonance imaging (MRI)Spatial distortion correctionDissertation to Obtain the Degree of Master in Biomedical EngineeringMagnetic Resonance Imaging (MRI) has been a major investigation and research focus among scientific and medical communities. So, new hardware with superior magnetic fields and faster sequences has been developed. However, these improvements result in intensity and spatial distortions, particularly in fast sequences, as Echo Plana Imaging (EPI), used in functional and diffusion-weighed MRI (fMRI and DW-MRI). Therefore, correction of spatial distortion is useful to obtain a higher quality in this kind of images. This project contains two major parts. The first part consists in simulating MRI data required for assessing the performance of Registration methods and optimizing parameters. To assess the methods five evaluation metrics were calculated between the corrected data and an undistorted EPI, namely: Root Mean Square (RMS); Normalized Mutual Information (NMI), Squared Correlation Coefficient(SCC); Euclidean Distance of Centres of Mass (CM) and Dice Coefficient of segmented images. In brief, this part validates the applied Registration correction method. The project’s second part includes correction of real images, obtained at a Clinical Partner. Real images are diffusion weighted MRI data with different b-values (gradient strength coefficient), allowing performance assessment of different methods on images with increasing b-values and decreasing SNR. The methods tested on real data were Registration, Field Map correction and a new proposed pipeline, which consists in performing a Field Map correction after a registration process. To assess the accuracy of these methods on real data, we used the same evaluation metrics, as for simulated data, except RMS and Dice Coefficient. At the end, it was concluded that Registration-based methods are better than Field Map, and that the new proposed pipeline produces some improvements in the registration. Regarding the influence of b-value on the correction, it is important to say that the methods performed using images with higher b’s showed more improvements in regarding metric values, but the behaviour is similar for all b-values.Faculdade de Ciências e TecnologiaSecca, MárioGodinho, FilipeLori, NicolasRUNMendes, Pedro Mota2011-12-15T10:56:23Z20112011-01-01T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfhttp://hdl.handle.net/10362/6333enginfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2024-03-11T03:37:36Zoai:run.unl.pt:10362/6333Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-20T03:16:51.411139Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse
dc.title.none.fl_str_mv Correction of spatial distortion in magnetic resonance imaging
title Correction of spatial distortion in magnetic resonance imaging
spellingShingle Correction of spatial distortion in magnetic resonance imaging
Mendes, Pedro Mota
Image quality
Image processing
Magnetic resonance imaging (MRI)
Spatial distortion correction
title_short Correction of spatial distortion in magnetic resonance imaging
title_full Correction of spatial distortion in magnetic resonance imaging
title_fullStr Correction of spatial distortion in magnetic resonance imaging
title_full_unstemmed Correction of spatial distortion in magnetic resonance imaging
title_sort Correction of spatial distortion in magnetic resonance imaging
author Mendes, Pedro Mota
author_facet Mendes, Pedro Mota
author_role author
dc.contributor.none.fl_str_mv Secca, Mário
Godinho, Filipe
Lori, Nicolas
RUN
dc.contributor.author.fl_str_mv Mendes, Pedro Mota
dc.subject.por.fl_str_mv Image quality
Image processing
Magnetic resonance imaging (MRI)
Spatial distortion correction
topic Image quality
Image processing
Magnetic resonance imaging (MRI)
Spatial distortion correction
description Dissertation to Obtain the Degree of Master in Biomedical Engineering
publishDate 2011
dc.date.none.fl_str_mv 2011-12-15T10:56:23Z
2011
2011-01-01T00:00:00Z
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/masterThesis
format masterThesis
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://hdl.handle.net/10362/6333
url http://hdl.handle.net/10362/6333
dc.language.iso.fl_str_mv eng
language eng
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Faculdade de Ciências e Tecnologia
publisher.none.fl_str_mv Faculdade de Ciências e Tecnologia
dc.source.none.fl_str_mv reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
instacron:RCAAP
instname_str Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
instacron_str RCAAP
institution RCAAP
reponame_str Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
collection Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
repository.name.fl_str_mv Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
repository.mail.fl_str_mv
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