Initial Feasibility and Challenges of Hyperpolarized Xe MRI in Neonates with Bronchopulmonary Dysplasia

Purpose: The underlying functional and microstructural lung disease in neonates who are born preterm (bronchopulmonary dysplasia, BPD) remains poorly characterized. Moreover, there is a lack of suitable techniques to reliably assess lung function in this population. Here, we report our preliminary experience with hyperpolarized Xe MRI in neonates with BPD.

Methods: Neonatal intensive care patients with established BPD were recruited (N = 9) and imaged at a corrected gestational age of median:40.7 (range:37.1, 44.4) wk using a 1.5T neonatal scanner. 2D Xe ventilation and diffusion-weighted images and dissolved phase spectroscopy were acquired, alongside H 3D radial UTE. Xe images were acquired during a series of short apneic breath-holds (˜3 s). H UTE images were acquired during tidal breathing. Ventilation defects were manually identified and qualitatively compared to lung structures on UTE. ADCs were calculated on a voxel-wise basis. The signal ratio of the Xe red blood cell (RBC) and tissue membrane (M) resonances from spectroscopy was determined.

Results: Spiral-based Xe ventilation imaging showed good image quality and sufficient sensitivity to detect mild ventilation abnormalities in patients with BPD. Xe ADC values were elevated above that expected given healthy data in older children and adults (median:0.046 [range:0.041, 0.064] cm s ); the highest value obtained from an extremely pre-term patient. Xe spectroscopy revealed a low RBC/M ratio (0.14 [0.06, 0.21]).

Conclusion: We have demonstrated initial feasibility of Xe lung MRI in neonates. With further data, the technique may help guide management of infant lung diseases in the neonatal period and beyond.