RESUMEN
OBJECTIVE: To investigate the image features, categories, and clinical significances of Pneumoconiosis Ш with large shadow. METHODS: The research is based on the analysis of image features of 168 pneumoconiosis Ш patients who are directly diagnosed by qualified medical professionals in our institution. These image features are large shadows bigger than 2 cm×1 cm which can be observed by high kilovolt chest radiographs, DR chest radiography and chest CT scan. RESULTS: Large shadows bigger than 2×1 cm show noticeable imaging characteristics, like distribution of superior and middle lung regions (95.2%) , irregular shapes (97.6%) , splayed or sausage like changes on both sides perpendicular with ribs (89.2%) , small shadows of pneumoconiosis (98.8%) , and convergence of large shadow to hilum or mediastinal (53.6%). CT scan is significantly better than DR radiography on detection rate of focal emphysema, focal cavities and swollen lymph node of mediastinal. CONCLUSION: Combining the image features of high kilovolt chest radiographs, DR chest radiographs and CT scan are the main methods to identify the shadows, and thus direct diagnose pneumoconiosis Ш; CT scan plays an important role in differential diagnosis.