Diffusion MRI studies in abstinent alcoholic patients to identify relationships between behavioural and microstructural evolution in the corpus callosum and the uncinate fasciculus

Details

Supervisors

Macq, Benoît ; Dricot, Laurence

Faculty

Ecole polytechnique de Louvain

Degree label

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

Abstract

Many ongoing research studies focus on elucidating the short-term effects of abstinence on the brain's microstructure in patients with alcohol use disorder (AUD). Diffusion MRI (dMRI) is recognised as a powerful tool for non-invasive analysis of the brain microstructures. It has also been observed that AUD is frequently accompanied by behavioural disorders, although the causal relationships between the two remain unclear. This study aimed at investigating the relationships between behavioural alterations and microstructural changes in the corpus callosum (CC) and the uncinate fasciculus (UF) among alcoholic patients following an 18-day abstinence period. A total of 53 patients were studied on the basis of data collected on the first and 18th day of abstinence and equivalent data were collected from 20 control subjects. Fibre tracts belonging to both structures were isolated from the complete brain tractography and 4 models (DTI, NODDI, DIAMOND and MF) were used to compute metrics, providing an insight into the microstructure of the white matter. At the same time, self-reported questionnaires were used to assess 5 behaviours: depression, obsession, compulsion, anxiety and fatigue. Comparisons between patients and controls at 1 and 18 days of abstinence confirmed the non-negligible impact of AUD on the microstructure of the CC and UF as well as on the behaviours of alcoholics. Although the changes in UFs remain largely non-significant in patients as compared to controls to be able to draw correlations with altered behaviour, noteworthy results were observed in the CC. Most of the behaviours studied were significantly correlated with changes within the posterior regions of the CC (including the isthmus and splenium). Obsession, on the other hand, was correlated with the most anterior region of the CC, the genu. Interpretation of the correlations with compulsion and obsession could indicate a reduction in inflammation in the splenium and the genu respectively, occurring in early stages of abstinence and suggesting a recovery process consistent with the behavioural improvements. Moreover, anxiety appears to be significantly correlated to an increase in volume and a reorganisation of fibres in the splenium. Further research on these results could be promising for a better understanding of the numerous mechanisms involved in AUD.