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Study Syllabus for Classification of Radiographs of Pneumoconioses

Radiograph Classification

Subset 1


For eight decades, the ILO has published guidelines on how to classify radiographs of patients with pneumoconiosis. In this section, the Guidelines for the Use of the ILO International Classification of Radiographs of the Pneumoconioses (Revised Edition 2011) will be reviewed. The discussion will follow the sequence of items found on the classification form provided by NIOSH for reporting classification of findings potentially associated with pneumoconiosis in chest radiographs of workers exposed to hazardous dust (form available on the NIOSH web site at:

The classification form allows for systematic recording of radiographic findings for all types of pneumoconiosis. It is designed for reporting the findings on a posteroanterior view of the chest, but this does not exclude the use of other views in the clinical assessment of a patient. The information recorded by means of the classification form may contribute to the evaluation of a worker for compensation but the ILO classification system itself is not intended to set or imply a level at which compensation may be payable.

The complete classification will be discussed in this subset, although an abbreviated classification may be used in whole or in part in some circumstances. For the abbreviated classification, less detailed recording is performed (e.g., pleural thickening is noted only with the symbol “PT”). The uncommon occurrence of pleural changes in CWP may in some settings allow use of the short classification for recording these findings, whereas use of the complete classification is more appropriate for recording the parenchymal opacities found in this entity. It is recommended that a statement be made in the “Comments” section of the form if the abbreviated classification is used.

No radiographic features are pathognomonic of dust exposure. Some radiographic findings seen with pneumoconiosis may also be present with other disease processes. Even if conditions other than pneumoconiosis are included within the radiologic differential diagnosis, the posteroanterior view should be classified if:

  • any pleural or parenchymal findings consistent with a pneumoconiosis are present, and
  • pneumoconiosis is included within the radiologic differential diagnosis

Some appearances are consistent with pneumoconiosis, others are not. Those that are consistent or potentially consistent should be classified and recorded, and those that clearly are not consistent should be indicated in the “Symbols” and “Comments” sections of the form.

If pneumoconiosis is thought to be a possible cause of appearances on the chest radiograph, then those appearances should be classified and recorded. Thus, if the findings might be secondary to pneumoconiosis but other etiologies are also to be considered, the classification for pneumoconiosis (Sections 2A through 3D) should be completed and the other potential etiologies also noted under 4A to 4E in the “Symbols” and “Comments” sections.

If pneumoconiosis is not at all in the differential diagnosis and all of the appearances are thought to be secondary to a process other than pneumoconiosis, then this should be indicated in Sections 2A and 3A, and the findings and opinion should be recorded under Sections 4A to 4E in the “Symbols” and “Comments” sections.