Variations of brain magnetic resonance imaging among manganese-exposed workers / 中华预防医学杂志

<p><b>OBJECTIVE</b>Variations of the signal intensities in the magnetic resonance (MR) T(1)-weighted image (T(1)WI) of globus pallidus among manganese(Mn)-exposed workers were explored to provide a scientific basis for exposed biomarker of manganese-injured central nervous system (CNS).</p><p><b>METHODS</b>The brain MR T(1) and T(2) WI in eighteen male asymptomatic Mn-exposed, eight manganism and nine healthy control workers were examined routinely by adopting a 1.5 Tesla signal superconducting system. The SIGP and the signal intensity in frontal white matter (SIFWM) in the same side were determined, then pallidal index (PI) was calculated. Concentration of MnO(2) in workplaces and content of manganese in red blood cell (MnRBC) among workers were respectively determined by flame atomic absorption spectrometer (AAS) and inductively coupled plasma-atomic emission spectrophotometry (ICP-AES). The follow-up investigation in the eight high Mn-exposed workers was made one year later.</p><p><b>RESULTS</b>The results showed that the median of air MnO(2) in smelting workplace was 0.64 mg/m(3)(0.07 - 5.40 mg/m(3)), which were respective 0.56 mg/m(3)(0.09 - 1.71 mg/m(3)) in power distribution room (low Mn-exposure) and 0.89 mg/m(3) (0.07 - 5.40 mg/m(3)) in furnace (high Mn-exposure). PI in the Mn-exposed and high Mn-exposed workers were both higher than those of the manganism and control workers(116.4 +/- 8.2, 119.0 +/- 7.9, 105.3 +/- 8.4 and 102.2 +/- 1.5, respectively. Mn vs control, t' = 7.146, P = 0.000; Mn vs manganism, t = 3.181, P = 0.004. High Mn-exposure vs control, t' = 7.446, P = 0.000; high Mn-exposure vs manganism, t = 3.763, P = 0.001). The increased signal in T(1)WI of globus pallidus was observed in Mn-exposed workers, especially in high Mn-exposed workers. The content of manganese in red blood cell of Mn-exposed and control workers was significantly higher than those of the manganism workers [(151.6 +/- 40.5) ng/ml, (149.2 +/- 21.3) ng/ml, (154.5 +/- 46.6) ng/ml, (144.4 +/- 14.2) ng/ml, (20.8 +/- 7.4) ng/ml respectively. The difference was significant in statistics. Manganism vs control, t = 20.206, P = 0.000; manganism vs Mn, t' = 13.144, P = 0.000; manganism vs low and high Mn, t' = 12.964, 9.957, respectively, P = 0.000]. Only a decreased median of air MnO(2) in furnace was found one year later (0.89, 0.31 mg/m(3), Z = -2.142, P = 0.032). The difference was significant in statistics.</p><p><b>CONCLUSION</b>Our data suggests that SIGP of MR T(1)WI among workers was obviously increased by manganese-exposure. PI may be taken as the signal of CNS injury which was induced by manganese-exposure.</p>

MRI Diagnosis of Intracranial Meningiomas (An Analysis of 63 Cases) / 实用放射学杂志

Objective To study the relationship between the MRI features and pathological types of intracranial meningiomas. Methods MRI findings of intracranial meningiomas in 63 cases proved by operation and pathology were analyzed retrospectively.Results Of 63 cases,62 cases were singular and one case was multiple lesions. The lesions were located in frontal,parietal and occipital regions nearby the convexity of the brain in 30 cases,in sellar region in 10,at sphenoidal crest in 8 , at olfactory sulcus in 5 and at other regions in 10. Isointense or slightly hypointense signal on T 1WI was found in 87.27% cases of meningiomas . On T 2WI, tumors had isointense or slightly hyperintense signal in 69.84%, obviously hyperintense signal in 19.05%,heterogenous texture signal in 7.94% and slightly low intense signal in 3.17%. Pathological type was included meningiomas meningothelial(n=29), meningiomas fibrous(n=11) , meningiomas psammomatous(n=8),angioblastic meningiomas (n=5) and meningiomas angiomatous(n=10). Conclusion It is great value in diagnosis of meningiomas with MRI. Meningiomas angiomatous show effecting of blood-vessel flowed empty with MR imaging.