Case 10--Continued

Section 6

Image 1



See the image below for correlation with the architectural distortion--tenting of pleura--in the anterior right upper lobe.



Architectural Distortion

In this lung, note the marked thickening of the visceral pleura.

Find where the pleura has folded into the lung parenchyma.

Find the curved deviation of the interlobar fissure caused by the scar.

Find the mild deviation of 2 large vessels toward the pleural infolding.

In HRCT image 1 above, the architectural distortion in the anterior right lung is an example of this pleural infolding.

Note that there is no honeycombing (see below) in this lung.


Section 7

More Advanced Disease

This is an example of a lung with more advanced disease.

Note pleural thickening at the base.

The normally smooth, lateral pleural margin shows architectural distortion, which is caused by irregular, subpleural fibrosis (causing subpleural nodules on HRCT).

Find a small subpleural scar (subpleural nodule)

Compare the abnormal parenchyma in the upper lateral, subpleural region to the more normal parenchyma medially. What is the abnormality?



The cause of the changes noted above is shown here. What is it?


Differential diagnosis of parenchymal bands with architectural distortion on HRCT: Asbestos-related lung disease, atelectasis, tuberculosis, sarcoidosis, and diffuse pulmonary fibrosis

Differential diagnosis of pleural infolding (rounded atelectasis): Asbestos-related pleuropulmonary disease, chronic renal failure, post coronary artery bypass graft surgery, healed pneumonias, and healed infarcts

Histologic differential diagnosis: The presence of asbestos bodies and a history of asbestos exposure distinguish this entity from other fibrosing diseases such as usual interstitial pneumonia, and fibrosis caused by a drug, organic and other inorganic dusts, radiation, or collagen vascular diseases.

Diagnosis: Asbestosis

Diagnostic features of asbestosis on HRCT: In a person with a history of asbestos exposure, the diagnosis of asbestosis can be based on the HRCT if three or more of the following abnormalities are present [1]:


1. Gamsu G, Salmon C, Warnock M, Blanc P. CT quantification of interstitial fibrosis in patients with asbestosis: a comparison of two methods. AJR 1995; 164:63-68.



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Tenting of pleura




























Subpleural line




























Centrilobular nodules


































Subpleural nodule




































Parenchymal band


































Pleural infolding



























Deviation of major fissure toward pleural infolding




























Vascular deviation toward pleural infolding































Honeycombing, consisting of small cystic spaces with thick walls (more on honeycombing later).




























This is an asbestos body, which is a thin asbestos fiber that has been coated with an iron-protein coat within a macrophage. The asbestos body is often found in areas of hemosiderin pigment, as indicated on the previous page (use the "back" button in the menu bar to return). The beaded appearance with tapered tips is characteristic, but other forms also occur. Note the thin, uncoated portions of the fiber. Occasionally, such bodies, referred to as ferruginous bodies, have a core of another fibrous material.