Abstract

This study was carried out to investigate the relationship between brain magnetic resonance imaging (MRI) and neurological findings in welders exposed to manganese fume. Thirty five welders from a bus manufacturing factory who were occupationally exposed to low dose manganese fume were examined. We collected the information on the demo graphic factors and welding careers. Laboratory investigations included blood and urine manganese concentration and blood chemistry. Brain MRI was checked, and high signal intensity of the globus pallidus was graded from 0 to 3 compared to the white matter of the frontal lobe. Neurologic examination wart carried out. The results were as follows ; 1. The mean age of workers was 48.3+/-5.7 years, mean duration of welding was 21.4 +/-5.6 Years. 2. On brain MRI, high signal intensity in the globes pallidus was observed in 27 workers (77.1%) Among them, 18 cases (66.7%) showed remarkably high signal intensity (grade 2) Mean concentration of blood manganese was higher in those with high signal intensity and correlated to the grade of high signal intensity (p=0.02) 3. On neurologic examination, no workers showed the finding of typical parkinsonism. But 11 workers (31.4%) showed subtle neurological abnormalities such as gait without associated arm movement, postural instability, intention tremor, and so on. Blood manganese concentration of neurologically abnormal group was 2.4+/-0.7 microgram/dL, which was significantly higher, compared to 1.8+/-0.7 microgram/dL of neurologically normal group (p=0.03). 4. Among 27 workers who showed high signal intensity on brain MRI, 10 workers (37%) were neurologically abnormal. Higher grade of signal intensity on globus pallidus showed higher rate of neurologic abnormality (p<0.05) Especially postural instability and gait without associated arm movement were prominent findings. These bindings suggest that high signal intensity on brain MRI might be associated with a prodromal sign of manganese intoxication. Careful neurologic examination should be tool lowed up on welders showing high signal intensity in the golbus pallidus of brain MRI.

• Keywords: Welder;Brain magnetic resonance imaging;High signal intensity;Neurologic abnormality