Lung ultrasound can detect a host of interstitial type diseases including acute pulmonary edema, acute respiratory distress syndrome, interstitial lung disease, and many others. This guide and attached video tutorial will walk you through how to detect and interpret the key findings in interstitial pulmonary diseases.
B-lines play a key role in detecting pathology on lung ultrasound. B-lines are vertical and MUST extend along entire length of the screen from the pleura. The following clip shows key features of B-lines.
The differential for interstitial disease is broad–as shown here. Differentiation, as it is for most imaging modalities, requires a consideration of details on history and physical examination. While pulmonary edema should be a primary consideration, context is critical. There are some subtle differences that can be used to differentiate cardiogenic vs non-cardiogenic edema (shown on next section).
An examination of the pleura of a patient with non-cardiogenic pulmonary edema will reveal interrupted pleura, sub-pleural consolidations, and occasional patched of non-sliding. Further, non-cardiogenic pulmonary edema can have areas of relatively normal parenchyma with sliding and A-lines, whereas B-lines are typically diffuse bibasilar or across the chest in pulmonary edema.
Interstitial changes can also be found in collapse. Generally, these findings are more localized either unilaterally or bibasilar. These findings can indeed progress from a couple of B-lines to more dense B-lines and to dense consolidation in the latter stages.
Lung ultrasound has a high sensitivity for interstitial pathology such as pulmonary edema, acute respiratory distress syndrome, ILD, and others. This section will cover the use of ultrasound for detection of an array of interstitial diseases, consolidation, and pneumonia.
Section contributors: Brian Buchanan, Jean Deschamps
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