Intralobar septal oedema: 'D' lines

Pulmonary fibrosis on the lateral chest radiograph: Kerley D lines revisited

Abstract

The retrosternal clear space (RCS) is a lucent area on the lateral chest radiograph located directly behind the sternum. The two types of pathology classically addressed in the RCS are anterior mediastinal masses and emphysema. Diseases of the pulmonary interstitium are a third type of pathology that can be seen in the RCS. Retrosternal reticular opacities, known as Kerley D lines, were initially described in the setting of interstitial oedema. Pulmonary fibrosis is another aetiology of Kerley D lines, which may be more easily identified in the RCS than elsewhere on the chest radiograph.

Teaching points

• The RCS is one of three lucent spaces on the lateral chest radiograph.

• Reticular opacities in the RCS are known as Kerley D lines.

• Pulmonary fibrosis can be seen in the RCS as Kerley D lines.

• Kerley D lines should be further evaluated with chest CT.

Radiology in Mendelson's syndrome

Four cases of Mendelson's syndrome (acid pulmonary aspiration) are presented. They all demonstrate an acute diffuse alveolar filling pattern. This appearance is by no means specific. However, in the absence of other causes for this pattern and of evidence of left ventricular failure the radiologist may alert the clinician to the correct diagnosis. Early recognition of this syndrome will result in prompt treatment which differs significantly from that of other causes of this radiographic appearance. The differential diagnosis is discussed.