Altered white matter microstructural integrity revealed by voxel-wise analysis of diffusion tensor imaging in welders with manganese exposure.
Chronic exposure to manganese (Mn), which can be an occupational hazard or can result from liver failure, is associated with adverse motor and cognitive outcomes. Evidence from previous neuroimaging and magnetic resonance spectroscopy studies suggested alteration of function in Mn-exposed brains. However, the effect of chronic exposure of the human brain to Mn on white matter (WM) structure has not yet been determined. In the present study, we used diffusion tensor imaging (DTI) to investigate whether welders exposed to Mn demonstrate differences in WM integrity, compared with control subjects. Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were measured on a voxel-wise basis in 30 male welders with exposure to Mn and in 19 age- and gender-matched control subjects. Direct comparison between welders and controls using investigator-independent Statistical Parametric Mapping (SPM) voxel-wise analysis of DTI metrics revealed a reduction of FA in the corpus callosum (CC) and frontal WM in Mn-exposed welders. Further, marked increases in RD and negligible changes in AD suggested that the microstructural changes in the CC and frontal WM result from compromised radial directionality of fibers in these areas, caused primarily by demyelination. Correlation analysis with neurobehavioral performance also suggested that the microstructural abnormalities were associated with subtle motor and cognitive differences in welders.
Department of Occupational and Environmental Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, South Korea.
Yangho
Y
Kim
Kyoung Sook
KS
Jeong
Hui-Jin
HJ
Song
Jae-Jun
JJ
Lee
Jee-Hye
JH
Seo
Gab-Chul
GC
Kim
Hui Joong
HJ
Lee
Hye Jung
HJ
Kim
Joon-Ho
JH
Ahn
Sin-Jae
SJ
Park
Suk Hwan
SH
Kim
Young Joo
YJ
Kwon
Yongmin
Y
Chang
D000328:Adult; D056324:Diffusion Tensor Imaging / Q000379:methods*; D006801:Humans; D008297:Male; D008345:Manganese / Q000008:administration & dosage / Q000009:adverse effects*; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000187:drug effects* / Q000473:pathology*; D016273:Occupational Exposure / Q000009:adverse effects*; D011597:Psychomotor Performance / Q000187:drug effects* / Q000502:physiology; D014896:Welding
D008345:Manganese