Diffusion Tensor Imaging Analysis of Subcortical Gray Matter in Patients with Alcohol Dependence

Abstract

To date, numerous studies have investigated the brain white matter abnormality in patients with alcohol dependence using diffusion tensor imaging (DTI). DTI has been primarily utilized to evaluate white matter integrity, it is now increasingly used to investigate microstructural changes of gray matter (GM), particularly the subcortical GM. We predicted that structural alterations may not only be restricted to the white matter but also found in subcortical GM in alcohol dependent patients (ADP). Possible relationships between brain microstructure assessed by magnetic resonance diffusion tensor imaging (DTI) and brain volumes were investigated in ADP. Diffusion and volumetric analyses were performed in 21 alcohol dependent men without neurological or somatic complications and in 21 healthy men. Raw volume and DTI parameters (i.e., fractional anisotropy, and diffusivity values) of six subcortical gray matter structures (amygdala, hippocampus, caudate, pallidum, putamen, thalamus) were measured in both hemispheres. Between-group (controls versus patients) comparisons of normalized volume, DTI parameters, as well as within-group correlation analyses between structural changes and clinical variables were carried out. Our results show that DTI measurements appear more sensitive than volume measurements, but the combination of the two methods can still be useful for detecting pathological changes. Major findings are change of macrostructures in left hippocampus and bilateral putamen and thalamus. ADP group exhibited significant volume reductions and change of microstructures in caudate and hippocampus, putamen. These findings can broaden our understanding of the neuroanatomical changes underlying ADP.