Porcine sidestream dark field imaging. Representative images are captured frames from a video recorded using the ImageJ software. (a) In situ normal pleural blood vessels before organ retrieval (black arrows). (b) In situ normal alveoli before organ retrieval. (c) Alveoli on EVLP in healthy, well-ventilated nonoedematous portions of the lung with the grey arrows inside an alveolus indicating the margin. (d) Alveoli on EVLP in haemorrhagic oedematous portions of the lung with the white arrows highlighting the interalveolar septum that contains haemoglobin giving it the black discolouration. Scale bar is 250 micrometers.