Fig. 1

Tracheal imaging setup. a A pig tracheal segment in the ex vivo sample chamber. The segment is pinned to a wax base using 25 Ga syringe needles to prevent movement. The Aeroneb nebuliser is shown inserted into the top of the sample chamber, and was used to deliver aerosolised isotonic or hypertonic saline to the tissue. A temperature and humidity sensor is visible on the left side of the container. The entire chamber was maintained at 37 °C, but relied on passive humidification from the wet gauze in the chamber. The same setup was used for imaging the sheep tracheal segments. b The tracheal tissue orientation, with imaging (x-ray beam) directions corresponding to those used in Figs. 3 and 4