OBJECTIVETo establish the optimal image post-processing parameters for digital chest radiography as preliminary research for introducing digital radiography (DR) to pneumoconiosis diagnosis in China.

METHODSA total of 204 pneumoconiosis patients and 31 dust-exposed workers were enrolled as the subjects in this research. Film-screen radiography (FSR) and DR images were taken for all subjects. DR films were printed after raw images were processed and parameters were altered using DR workstation (GE Healthcare, U.S.A.). Image gradations, lung textures, and the imaging of thoracic vertebra were evaluated by pneumoconiosis experts, and the optimal post-processing parameters were selected. Optical density was measured for both DR films and FSR films.

RESULTSFor the DR machine used in this research, the contrast adjustment (CA) and brightness adjustment (BA) were the main parameters that determine the brightness and gray levels of images. The optimal ranges for CA and BA were 115%∼120% and 160%∼165%, respectively. The quality of DR chest films would be optimized when tissue contrast was adjusted to a maximum of 0.15, edge to a minimum of 1, and both noise reduction and tissue equalization to0.The failure rate of chest DR (0.4%) was significantly lower than that of chest FSR (17%) (P < 0.05).

CONCLUSIONAfter appropriate image post-processing on DR machine purchased from GE Healthcare, the DR chest films can meet all requirements for the quality of chest X-ray films in the Chinese diagnostic criteria for pneumoconiosis.

Humans ; Image Processing, Computer-Assisted ; methods ; Pneumoconiosis ; diagnostic imaging ; Radiographic Image Enhancement ; standards ; X-Ray Film

OBJECTIVETo study the character of welder's pneumoconiosis on CT, pathology, and lung function.

METHODSTo contrast 185 welder's pneumoconiosis and 115 silicosis on CT, pathology, and clinical characters which were diagnosed between Jan 2008 and Dec 2013. Chest X-ray and lung function of 39 welder's pneumoconiosis patients were followed up after diagnosed 4~6 years later.

RESULTSAverage age and working years of welder's pneumoconiosis were 36.7 and 11.5, less than silicosis patients 58.8 and 22.1, respectively (P<0.05). Of all 185 welder's pneumoconiosis 98.4% were of stage I and no stage III, while in silicosis group stage I, stage II and stage III were 56.5%, 22.6% and 20.9%, respectively. The ratio differences between the two groups were statistically significant,P<0.05. 82.7% of welder's pneumoconiosis patients were observed pathologically moderate or above dust deposition in lung tissue while interstitial fibrosis level was just mild (97.6% patients) or no fibrosis (2.4% patients). By contrast, 60.0% silicosis patients pathologically showed moderate or above dust deposition while 77.8% were of moderate or above fibrosis. CT findings in welder' s pneumoconiosis were diffuse branching linear structure (38.9%), low density consistent size centrilobular micronodules (19.5%), or both (30.8%). Poorly-defined ground-glass attenuation centrilobular micronodules or widely ground glass shadow were observed in 6.4% welder's pneumoconiosis patents. 30.8% patients failed to reach the original stage when 39 welder's pneumoconiosis followed up chest radiograph.

CONCLUSIONChanges in welder's lung caused by welding fume were not only siderosis, but also interstitial fibrosis.

Adult ; Dust ; Fibrosis ; Follow-Up Studies ; Glass ; Humans ; Lung ; pathology ; Middle Aged ; Pneumoconiosis ; physiopathology ; Radiography, Thoracic ; Siderosis ; physiopathology ; Silicosis ; diagnosis ; physiopathology ; Welding