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Study Syllabus for Classification of Radiographs of Pneumoconioses

Radiograph Classification

Subset 4 – Small and Large Opacities

Large Opacity A

In marking the classification form, if both coalescent small opacities and an “A” large opacity are thought to be present, check both section 2C and symbol ax in Section 4B. If you are uncertain whether a density represents coalescent small opacities or an “A” large opacity, check section 2C or ax, whichever you think most likely, and note the possibility of the other type of abnormality in section 4, “Other Comments.”

The classification of large opacity “A” depends on the presence of one or more relatively homogeneous opacities, each greater than 10 mm in largest dimension, the sum of longest dimensions not exceeding 50 mm. It may be difficult to determine the precise measurements of such opacities because in many instances the edges or borders may be poorly defined or obscured by adjacent structures. Such lesions may be single or multiple and are almost always associated with a background of small opacities. If hilar migration of the large opacity or adjacent bullous emphysema occurs, the small opacities tend to become less conspicuous and less profuse. An “A” opacity may be entirely ill-defined but usually presents at least one fairly well-defined border. Unilateral large opacities may have characteristics similar to those of a fluid-filled cyst or carcinoma. If carcinoma is suspected, the concern must be indicated using the obligatory symbol ca in Section 4B with additional comments. If ca is selected in 4B, the appropriate physician must be notified.

Radiograph #46

Answer Key #46A
Answer Key #46B (Updated 9/28/2023)
Answer Key #46C (Updated 9/28/2023)
Answer Key #46D (Updated 9/28/2023)

Radiograph #46A shows small rounded opacities predominately in the all zones, r/r, and profusion of 2/2. This image shows superimposition of multiple small opacities and an area of coalescence, ax, in the first and second right anterior rib interspaces (arrow). Note that these areas are not homogeneous in character. No large opacity is present. Postsurgical changes in the left hemithorax are consistent with left upper lobectomy.

Radiograph #46B illustrates a well-defined large opacity, type “A,” in the right upper zone. Note its flat margin laterally. There is a background of small opacities, q/r, predominately in the upper and middle zones with minimal involvement of the right lower zone, and no involvement of the left lower zone. Profusion was determined to be 1/2. Coalescence, ax, is lateral to the right hilum in the right middle zone (arrow). Note the slight distortion and bullous emphysema adjacent to the large opacity.

Radiograph #46C. There is a large opacity category “B” in the right middle zone. There is the suggestion of an additional large opacity laterally in the left upper zone beneath the left clavicle. Note the elevation and distortion of the left hilum. Coalescence is identified at the left anterior second rib (arrow) and in the left lower zone along the lateral left diaphragm (arrow). Numerous small rounded opacities, r/q, are widespread, with a profusion of 3/3. Due to the suggestion of air space opacity in the right middle zone, an acute pneumonia or malignancy (ca) are considerations. The appropriate physician should be notified.

Radiograph #46D illustrates a poorly defined opacity in the right upper zone (arrow) that meets the criteria of an “A” opacity. The background of small opacities, q/q, with a profusion of 1/1 is consistent with a large opacity, however neoplasm should be considered. Once again, the appropriate physician should be notified. Suggestion of face on pleural plaque noted at the left base laterally.