Study Syllabus for Classification of Radiographs of Pneumoconioses
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Section 2: Parenchymal Abnormalities (Continued)
Profusion should be assessed separately for each of the six lung zones. In evaluating the profusion of small opacities within a lung zone, one must consider the total number of small opacities present. If more than one type of small opacity is present, they must all be considered in matching the zone with the ILO Standards for profusion. If small opacities are not uniformly distributed throughout a lung zone, one must estimate what the profusion would be if they were uniformly distributed. Since the report form permits only one expression of profusion, and since profusion often differs from one lung zone to another, the assessments of individual lung zones must be integrated (subjectively averaged). In integrating these values, lung zones that are uninvolved and any lung zones in which the profusion is 3 or more minor categories less than that of the zones of principal involvement should be discounted. In short, the integrated expression of profusion represents a statement of average profusion in only those lung zones that are significantly involved. It does not necessarily represent an average of the profusion of small opacities throughout the whole of both lungs.
Compare each lung zone of the subject radiograph with the ILO midrange standards, and check the box in the “profusion” block that best represents the overall integrated profusion of small opacities in the lungs using the conventions defined above:
- Include all shape/size small opacities in your judgment of profusion, not just the primary type.
- Estimate profusion assuming the opacities were evenly distributed in a lung zone, ignoring any lung zones that are uninvolved.
- Ignore any lung zones in which the profusion of small opacities is 3 or more minor categories less than in the principally involved zones.