Purpose
To determine feasibility of pulmonary MRI of neonatal lung structures enabled by combining two novel technologies: first, a 3D radial ultrashort echo time (UTE) pulse sequence capable of high spatial resolution full-chest imaging in non-sedated quiet-breathing neonates, and second, a unique, small-footprint 1.5T MRI scanner design adapted for neonatal imaging and installed within the Neonatal Intensive Care Unit (NICU).
Materials and Methods
Ten patients underwent MRI within the NICU, in accordance with an approved Institutional Review Board protocol. Five had clinical diagnoses of bronchopulmonary dysplasia (BPD), and five had putatively normal lung function. Pulmonary imaging was performed at 1.5T using 3D radial UTE and standard 3D fast gradient recalled echo (FGRE). Diagnostic quality, presence of motion artifacts, and apparent severity of lung pathology were evaluated by two radiologists. Quantitative metrics were additionally used to evaluate lung parenchymal signal.
Results
UTE images showed significantly higher signal in lung parenchyma (p <0.0001) and fewer apparent motion artifacts compared to FGRE (p = 0.046). Pulmonary pathology was more severe in patients diagnosed with BPD relative to controls (p = 0.001). Infants diagnosed with BPD also had significantly higher signal in lung parenchyma, measured using UTE, relative to controls (p = 0.002).
Conclusion
These results demonstrate the technical feasibility of pulmonary MRI in free-breathing, non-sedated infants in the NICU at high, isotropic resolutions approaching that achievable with CT. There is potential for pulmonary MRI to play a role in improving how clinicians understand and manage care of neonatal and pediatric pulmonary diseases.