Curvilinear Subpleural Line

A subpleural line is a thin curvilinear opacity a few millimeters or less in thickness that is usually less than 1 cm from the pleural surface and parallels the pleura.

This is a nonspecific finding that is classically described in patients with asbestos exposure (as in the case of the patient shown above), in whom the lines are thought to represent the proximal extent of a row of subpleural honeycomb cysts, peribronchiolar fibrosis (and resultant collapse of alveoli), or hypoventilation due to pleural thickening. Dependent subpleural lines can also be seen in normal subjects related to atelectasis.

References

• Aberle DR, Gamsu G, Ray CS. High-resolution CT of benign asbestos-related diseases: clinical and radiographic correlation. AJR Am J Roentgenol. 1988 Nov;151(5):883-91.
• Austin JH, Müller NL, Friedman PJ, Hansell DM, Naidich DP, Remy-Jardin M, Webb WR, Zerhouni EA. Glossary of terms for CT of the lungs: recommendations of the Nomenclature Committee of the Fleischner Society. Radiology. 1996 Aug;200(2):327-31.
• Lynch DA, Gamsu G, Aberle DR. Conventional and high resolution computed tomography in the diagnosis of asbestos-related diseases. Radiographics. 1989 May;9(3):523-51.