Hyperpolarized Helium-3 Diffusion-weighted Magnetic Resonance Imaging Detects Abnormalities of Lung Structure in Children With Bronchopulmonary Dysplasia

Purpose: The aim of the study was to determine whether hyperpolarized 3 He diffusion-weighted magnetic resonance imaging detects abnormalities in the lungs in children with bronchopulmonary dysplasia (BPD) as compared with age-matched normal children. Materials and Methods: All experiments were compliant with Health Insurance Portability and Accountability Act (HIPAA) and performed with Food and Drug Administration approval under an IND application. The protocol was approved by our Institutional Review Board, and written informed consent was obtained. Hyperpolarized 3 He diffusion-weighted magnetic resonance imaging was performed in 16 subjects with a history of preterm birth complicated by BPD (age range, 6.8 to 13.5 y; mean, 9.0 y) and in 29 healthy term-birth subjects (age range, 4.5-14.7 y; mean, 9.2 y) using a gradient-echo sequence with bipolar diffusion gradients and with measurements at 2 b values (0 and 1.6 s/cm). Age-related comparison of the whole-lung mean apparent diffusion coefficient (ADC), 90th percentile ADC, and percentage of whole-lung volume with ADC>0.2 cm/s between the 2 groups was examined using ordinary least-squares multiple regression. Results: The mean ADC was significantly greater in subjects with BPD (0.187 vs. 0.152 cm/s, P<0.001). The 90th percentile ADC and mean percentage lung volume with ADC>0.2 cm/s were also higher in the BPD group (0.258 vs. 0.215 cm/s, 30.3% vs. 11.9%, P<0.001 for both). The body surface area-adjusted ventilated lung volume was similar in the 2 groups (1.93 vs. 1.91 L, P=0.90). Conclusions: Children with BPD had higher ADCs and the same lung volumes when compared with age-matched healthy subjects, suggesting that children with BPD have enlarged alveoli that are reduced in number.