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Project: Applications of Computer Vision in Medicine: Magnetic Resonance Imaging Classification for Glioma Diagnosis
Timeline
Week 7 to Week 12: Work on your project. You have 6 weeks. The facilitators will be available in the labs during the lab hours for questions.
Week 12 (21st & 22nd of May 2024): Presentation of the projects during the lab hours. The schedule will be announced.
Grouping
Form groups of 3 students and include the first names and surnames of the group members on LMS Discussion board. This should have been done by now.
Applications of Computer Vision in Medicine: Magnetic Resonance Imaging Classification for Glioma Diagnosis
Background
Medical imaging is a critical application of Computer Vision (CV). In this project, we will apply CV techniques to Magnetic Resonance Imaging (MRI) for glioma diagnosis. Glioma is a type of malignant brain tumor with varying degrees of severity. Gliomas can be broadly categorized into Low-Grade Gliomas (LGG) and High-Grade Gliomas (HGG), with LGG being less aggressive and HGG being more aggressive. Accurate diagnosis is crucial for clinical decision-making as the intervention and prognosis significantly differ between LGG and HGG patients. Currently, the diagnosis involves both (i) non- invasive imaging studies and (ii) invasive histopathological examinations, with the latter being essential for a definitive diagnosis. However, invasive examinations, such as biopsy or surgical resection of the tumor tissue, pose high risks to patients. Therefore, there is a pressing need to perform. glioma diagnosis solely based on non-invasive imaging studies.
A commonly used medical imaging modality for non-invasive imaging studies is MRI. MRI uses strong magnetic fields and radio waves to construct volumetric images of the internal structures of the body. It is used for imaging patients with glioma due to its ability to provide excellent contrast between brain tumor and normal brain tissues. Glioma exhibits extreme heterogeneity in appearance and shape when visualized on MRI, making image-based diagnosis with the naked eye very challenging. However, LGG/HGG may have certain intrinsic, unique imaging features, suggesting the potential for leveraging CV techniques for image-based diagnosis.
Project Overview
In this project, our objective is to use CV techniques to classify patients with LGG or HGG based on their MRI studies. The project can be divided into the following steps.
• Step One: Data sourcing;
• Step Two: Visualization;
• Step Three: Feature Detection and Extraction;
• Step Four: Feature Selection;
• Step Five: Classification using SVM.
Step One: Data Sourcing
The dataset we are using is publicly available on Kaggle. You need to first register on Kaggle and download the dataset.
The dataset contains MRI of 369 patients with glioma. An MRI volume is a volumetric image comprising n slices (layers of the volume). Each slice comprises h × w pixels; for the entire volume, there are h × w × nvoxels (pixels in 3D). In this dataset, n=155 for every MRI volume; the MRI slices are stored as H5 files. The filenames follow the pattern volume_[volume ID]_slice_[slice ID], e.g., volume 1 slice_0 suggests the 0th slice of the 1st volume. Each H5 file contains four h × w images and three segmentation masks for three tumor sub-regions. The three tumor sub-regions include (i) the necrotic tumor core, (ii) the non-necrotic tumor core, and (iii) the surrounding tissues invaded by the tumor. For simplicity, the three segmentation masks can be merged to represent the whole tumor; however, you are free to perform. an analysis for each sub-region.
The four images detail the same anatomical position and differ in terms of image acquisition protocol. They can be considered as four different channels (sequences), similar to the R, G, B channels of a natural image; however, for subsequent operation, they have to be processed separately. The four images are stored inah × w × 4 array: the 1st, 2nd, 3rd, 4th (MATLAB)/0th, 1st, 2nd, 3rd (Python) ‘layer’ of the array corresponds to the T2 Fluid Attenuated Inversion Recovery (T2- FLAIR), native (T1), post-contrast T1-weighted (T1Gd), T2-weighted (T2) channel, respectively. An example of the four channels of the same anatomical position is shown in Fig.