Control study of chest CT imaging features of aluminosis and silicosis patients

Objective: To understand the chest CT features of aluminosis caused by alumina and to improve the understanding of the imaging findings of alumina pneumoconiosis. Methods: The chest CT findings of 17 cases of alumina-induced pneumoconiosis and 30 cases of silicosis (the control group) diagnosed in Zibo Occupational Disease Prevention Hospital from April 2015 to July 2020 were analyzed retrospectively. The characteristics of fibrosis of the two kinds of pneumoconiosis and the incidence of size, density, distribution, tractive bronchiectasis, pleural thickening and interlobular septal thickening of pneumoconiosis nodules were compared. Results: Alumina pneumoconiosis showed nodules with thickened interlobular septal of 66.67% (12/18) , honeycomb lung of 22.22% (4/18) , ground glass shadow of 61.11% (11/18) , simple nodules of 11.11% (2/18) , and no fusion mass. In the control group, the long-line fibrosis of nodules with thickened interlobular septal were 16.67% (5/30) , 6.67% (2/30) with honeycomb lung and ground glass density shadow, 23.33% (7/30) with fusion mass and 53.33% (16/30) with simple nodule. There were significant differences in CT findings of nodules with thickened interlobular septal, ground glass density shadow, fused mass and simple nodules between the two groups (P<0.05) . The interstitial beaded nodules were seen in 18 cases of alumina pneumoconiosis, 50.00% (9/18) of them were beaded nodules, 61.33% (46/75) of low density nodules and 38.89% (7/18) of central lobular nodules were seen in alumina pneumoconiosis. The average width of nodules was (1.29±0.38) mm. Central lobular nodules were seen in all 30 cases of silicosis, 10.00% (3/30) were mainly beaded nodules, low density nodules were 36.29% (90/248) , and the average width diameter of nodules was (1.85±0.58) mm. There were significant differences between the two groups (P<0.05) . Alumina pneumoconiosis was often accompanied by traction bronchiectasis, pleural thickening and interlobular septal thickening (11, 18, 17 cases, 61.11%, 100.00%, 94.44%) , compared with the control group (9, 18, 18 cases, 30.00%, 60.00%, 60.00%) . The differences were statistically significant (P<0.05) . The maximum CT value of noncalcified mediastinal lymphnodes in alumina pneumoconiosis was (103.43±26.33) HU, which was higher than that of the control group[ (75.22±16.70) HU], and the difference was statistically significant (P<0.05) . Conclusion: Alumina pneumoconiosis chest CT shows slightly low-density beaded nodules, thickened interlobular septal, and pulmonary interstitial fibrosis of ground-glass shadows, mostly combines with stretched bronchiectasis, thickened pleura, and mediastinum increased lymph node density.