Functional respiratory imaging provides novel insights into the long-term respiratory sequelae of bronchopulmonary dysplasia

RationaleBronchopulmonary dysplasia (BPD) is a common complication of preterm birth. Lung function and imaging are classically used to assess BPD. Functional Respiratory Imaging (FRI) combines a structural and functional assessment of the airways and their vasculature. We aimed to assess BPD with FRI and to correlate these findings with the clinical presentation.MethodsWe included 37 adolescents with a history of preterm birth (22 BPD cases and 15 preterm controls). The study protocol included a detailed history, lung function testing and CT (at TLC and FRC) with FRI. CT images were also assessed using the Aukland scoring system.ResultsBPD patients had lower FEV1/FVC (p=0.02) and impaired diffusion capacity (p=0.02).Aukland CT scores were not different between the two groups. FRI analysis showed higher lobar volumes in BPD patients at FRC (p<0.01) but not at TLC. Airway resistance was significantly higher in the BPD group, especially in the distal airways. Additionally, FRI showed more air trapping in BPD patients, in contrast to findings on conventional CT images.ConclusionThis study is the first to use FRI in research for BPD. FRI analysis showed higher lobar volumes in BPD patients, indicating air trapping and reduced inspiratory capacity. In contrast to Aukland CT scores, FRI showed more air trapping in the BPD group, suggesting that FRI might be a more sensitive detection method. Importantly, we also showed increased distal airway resistance in BPD patients. By combining structural and functional assessment, FRI may help to better understand the long-term sequelae of BPD.