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Study Syllabus for Classification of Radiographs of Pneumoconioses						Print
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										Radiograph ClassificationSubset 4 – Small and Large OpacitiesSymbol ax
Symbol **ax** refers to an area of coalescence of small opacities. The area may be of any dimension but is not homogeneous in character because the margins of individual small opacities are still identifiable. A large opacity “A” is more homogeneous. It should be noted that coalescence may occur with small rounded as well as with small irregular opacities. Coalescent small opacities (**ax**) and “A” large opacities may be present in the same radiograph and should be so classified. Additional projections or chest CT would likely resolve the issue. The distinction of whether a shadow represents coalescence vs a large opacity is not trivial; some federal and state agencies consider the presence of a large opacity as evidence of disability.
Radiograph #45 – Symbol ax
Answer Key #45A (Updated 9/28/2023)Answer Key #45B (Updated 9/28/2023)Answer Key #45CAnswer Key #45D
Radiograph #45 illustrates 3 examples of coalescent small opacities (images B, C, and D) and contrasts them with image A, which shows superimposition of opacities without coalescence.
**Radiograph #45A.** This image illustrates an excellent example of r/r – 3/3. The left lung shows superimposition of many small opacities but there is no coalescence. The normal vascular pattern is totally obscured. On the right there is a category A large opacity in the right upper zone, as well as coalescence (**ax**) along the upper right lateral chest wall. Note also hilar adenopathy (**hi**).
**Radiograph #45B.** An area of coalescence, **ax,** is seen on this image lateral to the left hilum (arrow) overlying the left fourth anterior rib. Large opacities are evident along the right lateral chest wall as opaque densities adjacent to areas of coalescence in which the margins of small opacities are still discernible. These large opacities would be classified as category “B” since the sum of their diameters is greater than 50 mm.
**Radiograph #45C** shows widespread rounded small opacities, **q/r,** with a profusion of 3/2. A good     example of coalescent small opacities is seen beneath the middle left clavicular shadow (arrow), and the left base overlying the 6th anterior rib (arrow). These densities are not considered to represent a large opacity because it is not homogeneous and the margins of the coalescing small opacities remain visible. This image also illustrates superimposition of small opacities and a large relatively homogeneous opacity where the sum of the long axis diameters is greater than 50 mm, therefore category “B”. Note the large opacity on the right is in the lower zone. Symbol di is checked.
**Radiograph #45D** once again shows widespread small rounded opacities, **r/r**, and profusion of 3/+. There is an area of coalescent small opacities (**ax**) over the anterior left second rib in this image. Large opacities are classified as “B” when are added together and superimposition of small opacities are also present.RADIOGRAPHS #43 AND #44Page 5 of 7RADIOGRAPH #46
							
					
							Last Reviewed:  April 26, 2023						Source: 	National Institute for Occupational Safety and Health
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        Syndicate homeStudy Syllabus for Classification of Radiographs of Pneumoconioses
Introductionplus icon
Preface
Appreciation to Contributors
Intent of the Self-study Syllbus
Getting Started
Clinical Overviewplus icon
Major Occupational Lung Diseasesplus icon
Pneumoconioses
Central Role of Diagnostic Imagingplus icon
Role of CT
Overview of Nonimaging Clinical Tools in Lung Disease Diagnosis
Appendix A
References
Pathology Overviewplus icon
Pulmonary Silicosis
Coal Workers’ Pneumoconiosis
Asbestos Pleuropulmonary Disease
Pathological-Clinical Correlations
References
Radiograph Classificationplus icon
SUBSET 1 – Radiograph Classification, #1 to #19plus icon
Introduction
Radiograph Identification
Section 1: Image Quality
Section 2: Parenchymal Abnormalities, #1 to #14
Section 3: Pleural Abnormalities, #15 to #19
Section 4: Any Other Abnormalities
Section 5
SUBSET 2 – Radiograph #20 to #27plus icon
Radiograph #20
Radiograph #21
Radiograph #22
Radiograph #23
Radiograph #24
Radiographs #25 to #27
SUBSET 3 – Radiograph #28 to #38plus icon
Radiographs #28 to #30
Radiographs #31 to #32
Radiographs #33 to #35
Radiographs #36 to #38
SUBSET 4 – Radiograph #39 to #46 (Small and Large Opacities)plus icon
Radiographs #39 to #40
Radiographs #41 to #42
Radiographs #43 to #44
Radiograph #45
Radiograph #46
SUBSET 5 – Classifications and Answer Keys, Radiographs #47 to #83
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