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Automatic detection and segmentation of brain lesions from 3D MR and CT images
Includes bibliographical references.
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| Main Author: | |
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| Other Authors: | |
| Format: | Thesis |
| Language: | English |
| Published: |
Department of Electrical Engineering
2014
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| _version_ | 1867613327994126336 |
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| access_status_str | Open Access |
| author | Mokhomo, Molise |
| author2 | Nicolls, Fred |
| author_browse | Mokhomo, Molise Nicolls, Fred |
| author_facet | Nicolls, Fred Mokhomo, Molise |
| author_sort | Mokhomo, Molise |
| collection | Thesis |
| description | Includes bibliographical references. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/9089 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:34:23.309Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2014 |
| publishDateRange | 2014 |
| publishDateSort | 2014 |
| publisher | Department of Electrical Engineering |
| publisherStr | Department of Electrical Engineering |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/9089 Automatic detection and segmentation of brain lesions from 3D MR and CT images Mokhomo, Molise Nicolls, Fred De Jager, Gerhard Muller, N Includes bibliographical references. The detection and segmentation of brain pathologies in medical images is a vital step which helps radiologists to diagnose a variety of brain abnormalities and set up a suitable treatment. A number of institutes such as iThemba LABS still rely on a manual identification of abnormalities. A manual identification is labour intensive and tedious due to the large amount of medical data to be processed and the presence of small lesions. This thesis discusses the possible methods that can be used to address the problem of brain abnormality segmentation in MR and CT images. The methods are general enough to segment different types of abnormalities. The first method is based on the symmetry of the brain while the second method is based on a brain atlas. The symmetry-based method assumes that healthy brain tissues are symmetrical in nature while abnormal tissues are asymmetric with respect to the symmetry plane dividing the brain into similar hemispheres. The three major steps involved in this approach are the symmetry detection, tilt correction and asymmetry quantification. The method used to determine the brain symmetry automatically is discussed and its accuracy has been validated against the ground-truth using mean angular error (MAE) and distance error (DE). Two asymmetric quantification methods are studied and validated on real and simulated patient’s T1- and T2-weighted MR images with low and highgrade gliomas using true positive volume fraction (TPVF), false positive volume fraction (FPVF) and false negative volume fraction (FNVF). The atlas-based method is also presented and relies on the assumption that abnormal brain tissues appear with intensity values different from those of the surrounding healthy tissues. To detect and segment brain lesions the test image is aligned onto the atlas space and voxel by voxel analysis is performed between the atlas and the registered image. This methods is also evaluated on the simulated T1-weighted patient dataset with simulated low and high grade gliomas. The atlas, containing prior knowledge of normal brain tissues, is built from a set of healthy subjects. 2014-11-05T03:35:37Z 2014-11-05T03:35:37Z 2014 Master Thesis Masters MSc http://hdl.handle.net/11427/9089 eng application/pdf Department of Electrical Engineering Faculty of Engineering and the Built Environment University of Cape Town |
| spellingShingle | Mokhomo, Molise Automatic detection and segmentation of brain lesions from 3D MR and CT images |
| thesis_degree_str | Master's |
| title | Automatic detection and segmentation of brain lesions from 3D MR and CT images |
| title_full | Automatic detection and segmentation of brain lesions from 3D MR and CT images |
| title_fullStr | Automatic detection and segmentation of brain lesions from 3D MR and CT images |
| title_full_unstemmed | Automatic detection and segmentation of brain lesions from 3D MR and CT images |
| title_short | Automatic detection and segmentation of brain lesions from 3D MR and CT images |
| title_sort | automatic detection and segmentation of brain lesions from 3d mr and ct images |
| url | http://hdl.handle.net/11427/9089 |
| work_keys_str_mv | AT mokhomomolise automaticdetectionandsegmentationofbrainlesionsfrom3dmrandctimages |