Introduction

Bronchopulmonary dysplasia (BPD) is characterized by an arrest in alveolar and pulmonary vascular development. We hypothesize that small pulmonary vessels are less developed in preterm born infants with BPD as compared to controls.  

Methods

Chest CT scans were performed in infants with severe BPD and term born, age-matched controls, in whom CT scans were reported normal by a paediatric radiologist. CT scans were acquired in supine position with a free-breathing protocol on SOMATOM Drive and Force scanners (Siemens, Erlangen, Germany). Using an artificial intelligence based algorithm, blood vessel volume was first quantified, and subsequently pulmonary vessels volume was categorized in 4 groups according to cross sectional area:  2mm² (BV2), 2-5 mm² (BV2_5), 5-10 mm² (BV5_10) and 10 mm²  (BV10) (Fluidda, New York, USA). These 4 measures were expressed as percentage of total blood volume to account for body size. Differences between the groups were assessed by Mann-Whitney U test.

Results

In this pilot study, we included 10 infants with BPD (mean gestational age 27.5 weeks (SD2.2); mean corrected age at chest CT 7.1 months (SD 2.0)) and 8 controls (mean age 4.2 months (SD4.1)). BV2_5% was significantly smaller in BPD patients, while BV10% tended to be higher.

Conclusion

Infants with BPD tend to have lower percentages of pulmonary small vessel blood volume and higher percentages of larger vessel blood volume when compared to controls. These results suggest impaired small vessel growth among BPD patients.