Intracranial aneurysms occur in approximately one out of 20 to 30 people and are typically asymptomatic. One quarter of the aneurysms will rupture during patient's lifetime, which can cause a hemorrhagic brain stroke - a serious condition with a high mortality rate (50%), while 66% of survivors will suffer from permanent neurological deficits. Among such bleedings there 20% of sudden deaths that occur out of hospital environments.
Diagnosis of intracranial aneurysms is based on computed tomography or magnetic resonance angiography (CTA or MRA, respectively) imaging, whereas neuroradiologists use programs with graphic user interfaces that mostly only render 2D slices of 3D images, thereby depicing simultaneously only a small fraction (0,7% of the whole image). Therefore, to detect the aneurysms and evaluate their 3D morphology, a good mental reconstruction of these structures is needed, which is gained from the past experiences. Consequently their resulting decisions about further treatments could be somewhat subjective.
In this thesis we developed and evaluated a computer program with a graphical user interface, which allows to detect potential aneurysm locations in 3D MRA and CTA images with a high sensitivity rate (>95% of all aneurysms). Key parts of the program are modules developed using deep learning and machine learning methods: (i) module for segmentation of intracranial vessels in CTA images, (ii) module for segmentation of intracranial vessels in MRA images and (iii) module for aneurysm detection from intracranial vessel segmentations. The graphical user interface allows 3D rendering of vessel and aneurysm segmentation, 2D slice-wise display of the 3D image and manual annotation tools, which enable objective aneurysm morphology evaluation and thus an evidence-based treatment decision-making.
The use of said program allows for an automatic, faster and more accurate diagnosis of intracranial aneurysms, which would relieve medical staff's workload and, at the same time, enable screening imaging tests so as to lower death rates caused by spontaneous ruptures of undiagnosed and untreated intracranial aneurysms. On the other hand, the morphology quantification is the basis for future rupture risk assessment and thus helpful in determining the optimal and timely treatment.
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