MR structural and functional changes in patients with long-term abstinence of methamphetamine

Abstract

Objective To investigate the changes of brain gray matter volume (GMV) and brain activity in patients with long-term methamphetamine (MA) abstinence compared with healthy controls. Methods This study included 44 abstinent MA patients and 40 demographically equivalent healthy controls. Structural magnetic resonance imaging (MRI) and resting-state functional MRI (rs-fMRI) were obtained on Siemens 3.0 T MR. Differences in GMV between abstinent MA group and control group were assessed using voxel-based morphometry (VBM) method. Within each region showed significant differences between two groups, the value of the fractional amplitude of low frequency fluctuation (fALFF) was calculated using the rs-fMRI data. Differences of fALFF between groups were also evaluated. Furthermore, partial correlation coefficients adjusted for age, years of education, smoking and drinking were calculated in the abstinent MA group to assess associations between the mean GMV and fALFF values in significant clusters and variables of MA use and abstinence. Results Compared with controls, abstinent MA group showed increased GMV in the right cerebellum crus and decreased GMV in the right calcarine. While fALFF values within bilateral cerebellum crus in abstinent MA patients were significantly increased. Moreover, GMV of the left cerebellar crus was positively correlated with the withdrawal time among abstinent MA patients. Conclusions Both structural and functional abnormalities were found in abstinent MA patients even after long-term abstinence. The positive correlation between GMV of left cerebellum crus and abstinent duration suggested that prolonged abstinence may be beneficial to brain recovery. The fALFF of the right calcarine was increased even with decreased GVM in the abstinent MA group. It indicates that the brain activity of this area is increased, which may imply that drug cue-induced craving is significant among methamphetamine patients even after long-term abstinence. Key words: Methamphetamine; Magnetic resonance imaging; Voxel-based morphometry; Fractional amplitude of low frequency fluctuation