Purpose or Case Report: Congenital pulmonary airway malformations (CPAM), bronchopulmonary sequestrations (BPS), and hybrid lesions are the most common congenital lung lesions. They are primarily diagnosed prenatally via ultrasound and further characterized by MRI. While most affected neonates are asymptomatic at birth, some may experience varying severities of respiratory distress requiring intervention. We seek to develop a prognostic model for prediction of post-natal outcomes in patients with congenital lung lesions using fetal MRI calculated observed to expected normal lung volume (O/E NLV).
Methods & Materials: We did an IRB approved, retrospective study of patients with congenital lung lesions who underwent fetal MRI and received pre- and post-natal care at our institution from 2006 to 2016. 163 cases were referred to our institution for prenatal diagnosis of CPAM, BPS, or hybrid lesion. 68 of these patients had prenatal MRI performed at our institution. 8 patients were excluded due to "disappearing" lesion at the time of MRI or non diagnostic study. Statistical analysis was performed using Chi-square and Student’s t-test. MRI was reviewed by 2 pediatric radiologists to determine volume of normal lung (NLV), defined as the difference between total lung volume (TLV) and the volume of the lesion. NLV was normalized against published lung volumes by gestational age (O/E NLV). Imaging parameters were correlated with respiratory outcomes at birth including respiratory symptoms at birth, need for oxygen supplementation, mechanical ventilation, and delay in feeding.
Results: Mean gestational age at fetal MRI was 23.3 ± 3.0 weeks with a mean O/E NLV of 0.74 ± 0.26. Mean gestational age at birth was 38.4 ± 2.7 weeks. 14 of those neonates who had prenatal MRI had respiratory distress at birth. Requirement for oxygen supplementation at birth was observed in 12 of those patients and mechanical ventilation was necessary in the remaining 2 patients. O/E NLV did not significantly correlate with symptomatology at birth (p=0.15) or delay in feeding (p=0.14). O/E NLV did significantly correlate with requirement for supplementary oxygen (p=0.05) and requirement for mechanical ventilation (p=0.05) with a mean O/E NLV of 0.62 ± 0.17 and 0.4 ± 0.005 respectively.
Conclusions: Fetal MRI calculated O/E NLV ratio may be helpful in predicting respiratory prognosis at birth in patients with congenital lung lesions.