Correction of spatial distortion in magnetic resonance imaging
Autor(a) principal: | |
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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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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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1799137817503203328 |