Diffusion tensor imaging of major white matter tracts in active and recently abstinent methamphetamine users

Abstract

Aims: Methamphetamine has been a popular recreational drug for decades. Diffusion tensor imaging studies in abstinentmethamphetamine users have found reductions in fractional anisotropy in frontal white matter, suggesting axonal injury and inflammation. To date, no tractography studies have been carried out in participants with methamphetamine addiction; therefore, this study aimed to investigate microstructural changes within 18 major white matter tracts of active and recently abstinent methamphetamine users. Methods: Imaging was undertaken using a 3.0 T Siemens Magnetom Skyra system and a diffusion-weighted echo-planar imaging sequence with b=1500 s/mm2 and 64 directions. Data were acquired from 11 active methamphetamine users, 6 recently abstinent users aged 22–45, and compared with 9 healthy controls using the FDT toolbox within FSL 5.0, and TRACULA within FreeSurfer. One-way analysis of variance was carried out to determine differences between groups (p<0.05). Results: Statistical analysis revealed diffusion indices differed significantly in some white matter tracts across the three groups – fractional anisotropy in the right anterior thalamic radiation, axial diffusivity in the left uncinate fasciculus, angular bundle and temporal sectionof the right superior longitudinal fasciculus, and radial diffusivity in the left corticospinal tract and right anterior thalamic radiation. Post-hoc comparisonusingGabriel’s procedure indicated that recently abstinent methamphetamine users displayed significantly lower fractional anisotropy and higher diffusivity than current methamphetamine users. Conclusions: Altered diffusion indices were observed in some white matter tracts of abstinent methamphetamine users, compared to current users, suggesting that microstructural damage may follow drug cessation and abstinence. Financial support: OakleyMental Health Research Foundation.