Identifying the microstructural changes for alcoholic patients during short-term abstinence via diffusion Magnetic Resonance Imaging

Details

Supervisors

Macq, Benoît ; Dricot, Laurence

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil biomédical, à finalité spécialisée

Abstract

Diffusion magnetic resonance imaging is powerful tool to characterise the microstructural state of the brain as well as its changes over time. It has therefore been used for years now to evaluate the impact of several pathologies. This paper focuses on the impact of short-term abstinence on alcohol use disorder. A study on a set of 35 patients was conducted in order to have a better insight into the microstructural changes in their brain and the potential reversible damages of alcohol. For each subject, two scans, one on first day of an abstinence program and second 18 days later, were considered to assess the influence of short-term abstinence. Several microstructural models were applied on those diffusion data to retrieve the evolution of different metrics as well as the biological implications they have. The behavioral aspects of the subjects were also taken into consideration to spot any direct correlation between the alcoholism symptoms and changes of microstructural integrity. From those tests, two tendencies were observed among the patients which enabled to divide them into two clusters. The first cluster did not show significant changes in the course of abstinence. By contrast, the second cluster showed a high number of rearrangements in the structures of the limbic system, the cerebellum, its peduncles and the cortico-ponto cerebellar pathway. The evolution of the metrics can however translate two opposite phenomena linked with inflammation: a disinflammation of the extra-axonal space in those structures, suggesting a recovery process, or an inflammation of the fibers, suggesting a continued progression of the damages. The impact of abstinence on some patients is undeniable and further analyses should be performed on biological data to identify which hypothesis (inflammation or further damage) reflects the actual evolution of the brain during short-term abstinence. The recovery hypothesis seems to be the most appropriate one, regarding the evolution of the behavioral data.