Heavy smokers show abnormal microstructural integrity in the anterior corpus callosum: a diffusion tensor imaging study with tract-based spatial statistics.
BACKGROUND
Abnormal macrostructural brain abnormalities in both gray matter and white matter have been reported in cigarette smokers. However, less is known about white matter microstructure in heavy cigarette smokers. In this study, we used diffusion tensor imaging (DTI) to investigate the integrity of the white matter microstructure in heavy smokers.


METHODS
Thirty-four heavy smokers and 34 non-smokers participated in this study. Whole brain analysis of fractional anisotropy (FA) was performed using tract-based spatial statistics (TBSS) to detect abnormal white matter regions between groups. Volume-of-interest (VOI) analysis was used to investigate changes in diffusivity indices in the regions showing FA abnormalities. Multiple regression analysis was applied to assess the relationships between diffusion indices and smoking-related variables in heavy smokers.


RESULTS
Compared with non-smokers, heavy smokers had lower FA in the left anterior (i.e., the genu and rostral body) corpus callosum while exhibiting no areas of higher FA. In the affected region, FA reduction was accompanied by a significantly decreased axial diffusivity and increased radial diffusivity, which suggests that axonal damage and disrupted myelin integrity may be associated with the degraded white matter integrity in heavy smokers. Moreover, significant positive correlations were found between both radial diffusivity and mean diffusivity and the duration of regular smoking.


CONCLUSIONS
Our findings suggest that heavy smokers demonstrate abnormal integrity of the white matter microstructure in the anterior corpus callosum, which is related to the duration of regular smoking. In addition, our study may increase the understanding of the neurobiological basis of chronic cigarette smoking.
Wuhan Center for Magnetic Resonance, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China.
Fuchun
F
Lin
Guangyao
G
Wu
Ling
L
Zhu
Hao
H
Lei
D000328:Adult; D016880:Anisotropy; D003337:Corpus Callosum / Q000473:pathology*; D003627:Data Interpretation, Statistical; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D012907:Smoking / Q000473:pathology*