Subpleural Curvilinear Line

A subpleural curvilinear line is a thin curved line seen on high-resolution CT within about a centimeter of the lung surface, running parallel to the chest wall. In asbestos-exposed people it is one of the early CT signs that can suggest asbestosis, although it can also appear for other reasons, including simple collapse of lung tissue while lying down.

Origin

The finding was described in high-resolution CT studies of asbestos-exposed workers in the 1980s, as CT began to show lung scarring too early or slight to appear on chest X-rays.

Significance in Asbestos Context

Asbestosis begins around the small airways near the lung surface, especially in the lower back portions of the lungs, so early changes on CT tend to appear there. Subpleural curvilinear lines, together with small dots and branching lines near the surface, thickened lines between lung lobules, and bands running into the lung, are among the findings radiologists look for. No single sign is specific: the same line can come from dependent atelectasis, a temporary collapse of the lowest part of the lung when a person lies on their back. For that reason the scan is often repeated with the patient lying face down (prone imaging); a line that disappears was probably positional, while one that persists is more likely to reflect fibrosis. For a claim, these CT findings help support a diagnosis of asbestosis when combined with the exposure history, breathing tests and, where used, a B-read of the chest X-ray. A radiologist experienced with asbestos disease reads them most reliably.

Example Sentence

The prone HRCT images still showed subpleural curvilinear lines in both lower lobes, consistent with early asbestosis.

Related Terms

High-Resolution CT (HRCT), Asbestosis, Interstitial Fibrosis, Honeycombing, Atelectasis, Ground-Glass Opacity, Parenchymal Fibrosis

Notes

• Ask whether your CT included prone images; they help separate real scarring from positional changes.
• One CT sign alone does not establish asbestosis; doctors weigh it with breathing tests and exposure history.
• Keep the CT images on disc or in a portal so later scans can be compared.