Increased fetal lung T2 signal is not due to increasing surfactant concentration: an in vitro T2 mapping analysis.

OBJECT: The aim of this study was to perform in vitro T2 mapping of serial dilutions of pharmaceutical surfactant. MATERIALS AND METHODS: Magnetic resonance imaging. Magnetic resonance scanning was performed on serial dilutions of surfactant on large bore clinical magnets at a field strength of 1.5 T Philips and 3.0 T (Achieva TX, Philips Healthcare, the Netherlands). RESULTS: The curves demonstrate a small increasing trend between surfactant concentration and R2 (shortened T2's), with a 7.3% increase in R2 for each doubling of surfactant concentration (95% confidence interval: 6.1-8.6%, p < 0.001). CONCLUSIONS: The increasing lung/liver T2 signal ratio seen in fetal lungs with increasing gestational age is not due to increasing surfactant concentration. © 2016 John Wiley & Sons, Ltd.