Fig. 8From: Chest imaging using signs, symbols, and naturalistic images: a practical guide for radiologists and non-radiologistsDark bronchus sign. The figure shows a patent bronchial structure (white arrow)—which appears slightly dark—in the context of lung parenchyma area with a ground glass appearance. The dark bronchus sign is very useful to recognize pulmonary infection by Pneumocystis jiroveciiBack to article page