Interstitial pulmonary edema can be demonstrated by ultrasound. Thickening of the interlobular septa causes linear reverberation artefact perpendicular to the chest wall.

CT demonstrates thickened bronchial walls due to interstitial edema.

Pulmonary edema is due to accumulation of fluid in the extravascular compartments of the lung and interstitial edema precedes alveolar edema.