Information
- Publication Type: Master Thesis
- Workgroup(s)/Project(s):
- Date: January 2015
- Second Supervisor: Katja Bühler
- First Supervisor:
Abstract
In medical diagnosis, the spine is often a frame of reference and so helps to localize diseases (e.g. tumors) in the human body. Automated spine labeling approaches are in demand, in order to replace time consuming, manual labeling by a radiologist. Different approaches have already been proposed in the literature, mainly for Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) data. While CT scans exhibit a generalized intensity scale, MR images come with a high variability within the data and hence the tissues. Several factors influence the appearance of vertebrae and intervertebral disks in MRI data: different scanners, changes of acquisition parameters, magnetic field inhomogeneities or age-related, structural changes of the spinal anatomy. These factors compound the development of semi- and fully automatic spine labeling systems.The main goal of this thesis is to overcome these variations and find a generalized representation for different kinds of MR data. Furthermore, it aims for a semi-automatic labeling approach on these preprocessed scans where the user has to provide an initial click. Entropyoptimized Texture Models are applied to normalize the data to a standardized, reduced intensity scale.With Probabilistic Boosting Trees, intervertebral disk feature points are detected, whereby the disk center is selected with a Shape Particle Filter.
The results achieved with the proposed pipeline are promising in terms of data normalization, timing and labeling accuracy. With a mean overall processing time of 6.0 s for normalizing and labeling a dataset (0.8 s per disk), the algorithm achieves a precision of 92.4% (recall = 86.8%). Using a higher resolution of the data for disk detection (average timing of 1.6 s per disk resp. 12.4 s per dataset), reduces the number of missed disk candidates and hence increases the recall to 91.7% (with a precision of 91.9%).
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@mastersthesis{Wimmer_Maria_2015_SAS, title = "Semi-Automatic Spine Labeling on T1- and T2-weighted MRI Volume Data", author = "Maria Wimmer", year = "2015", abstract = "In medical diagnosis, the spine is often a frame of reference and so helps to localize diseases (e.g. tumors) in the human body. Automated spine labeling approaches are in demand, in order to replace time consuming, manual labeling by a radiologist. Different approaches have already been proposed in the literature, mainly for Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) data. While CT scans exhibit a generalized intensity scale, MR images come with a high variability within the data and hence the tissues. Several factors influence the appearance of vertebrae and intervertebral disks in MRI data: different scanners, changes of acquisition parameters, magnetic field inhomogeneities or age-related, structural changes of the spinal anatomy. These factors compound the development of semi- and fully automatic spine labeling systems. The main goal of this thesis is to overcome these variations and find a generalized representation for different kinds of MR data. Furthermore, it aims for a semi-automatic labeling approach on these preprocessed scans where the user has to provide an initial click. Entropyoptimized Texture Models are applied to normalize the data to a standardized, reduced intensity scale.With Probabilistic Boosting Trees, intervertebral disk feature points are detected, whereby the disk center is selected with a Shape Particle Filter. The results achieved with the proposed pipeline are promising in terms of data normalization, timing and labeling accuracy. With a mean overall processing time of 6.0 s for normalizing and labeling a dataset (0.8 s per disk), the algorithm achieves a precision of 92.4% (recall = 86.8%). Using a higher resolution of the data for disk detection (average timing of 1.6 s per disk resp. 12.4 s per dataset), reduces the number of missed disk candidates and hence increases the recall to 91.7% (with a precision of 91.9%).", month = jan, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", URL = "https://www.cg.tuwien.ac.at/research/publications/2015/Wimmer_Maria_2015_SAS/", }