Left atrium fibrosis quantification in atrial fibrillation patients: an open issue

Atrial fibrillation is the most common arrhythmia and its incidence is expected to increase due to population ageing. This disease is related to an increased risk of stroke, thromboembolism, cardiac arrest, dementia and mortality. Atrial fibrillation is associated with electrical, contractile and structural remodeling in the left atrium and it is sustained by the co-presence of an arrhythmogenic trigger and a proarrhythmic substrate. One of the main mechanisms that contribute to this process is atrial fibrosis. Detection and quantification of fibrotic tissue are possible using late gadolinium enhanced magnetic resonance imaging (LGE-MRI). Quantification of fibrosis burden through this technique could be helpful in predicting the outcome of ablation, allowing the selection of patients that could undergo the procedure. The main problem is represented by the lack of a standardized and reproducible method to locate and quantify fibrosis in left atrium. The main aim of this thesis is to evaluate different algorithms, which have been proposed in literature, to quantify left atrium fibrosis in atrial fibrillation patients, implementing and testing them on a dataset of patients. The algorithms that have been analysed are histogram-based reference, histogram-based reference with dynamic thresholding approach, nulled myocardium-based reference, blood pool-based reference, full width at half maximum, maximum scar density percentage and image intensity ratio.