LSC Abstract – Visualization of neonatal lung injury associated with mechanical ventilation using x-ray dark-field radiography

Background: Mechanical ventilation (MV) and the supplementation of oxygen-rich gas, often needed in postnatal resuscitation procedures, are known to be main risk factors for impaired pulmonary development in the preterm and term neonates. We analyzed whether the advance from conventional x-ray technology to x-ray dark-field radiography can improve visualization of early lung injury induced by MV and hyperoxia in neonatal mice. Methods: 5-7-day-old wild type C57BL/6 mice were mechanically ventilated with oxygen-enriched gas (MV-O 2 ; FiO 2 0.4) for 2 or 8 hours. Unventilated, spontaneously breathing littermates were kept in FiO 2 0.4 for 2 and 8 hours or in room air. After pulmonary function testing, the animals were imaged using a prototype small-animal x-ray dark-field scanner before standardized fixation for histologic analysis. Results: X-ray dark field of neonatal mice undergoing hyperoxia and MV-O2 revealed increasing loss of x-ray small-angle scattering when compared to the images obtained from animals kept in room air. The observed changes assessed by imaging correlated well with results of histologic analysis and were found to yield superior differentiation than lung function testing. Conclusion: The present study was able to show, that X-ray dark-field radiography acquired with a grating interferometer visualizes already minor changes in the morphology of the developing lung, caused by hyperoxia or MV-O 2 . In the future, this imaging technique can be applied to provide early diagnosis and monitor treatment regimen in neonatal lung injury by appropriate surveillance protocols.