Diffusion-weighted MR imaging and apparent diffusion coefficient of the normal fetal lung: preliminary experience

OBJECTIVE: To assess if a correlation is present between apparent diffusion coefficient (ADC) values and normal lung maturation during gestation to define potential reference values as indicators of the lung development. METHODS: Our study included 50 pregnant women (gestational age, GA: 18-36 weeks), with normal fetal development of lungs assessed by a previous obstetric ultrasound (US), and then confirmed by our magnetic resonance (MR) examination. We used T2-weighted sequences, diffusion-weighted imaging sequences (DWI) and ADC maps for studying pulmonary tissue. In all cases the resulting ADC values were related to GA using Pearson correlation. RESULTS: ADC values ranged from 1,2 microm(2)/ms at 18 weeks' gestation to 3,9 microm(2)/ms at 36 weeks' gestation with a mean value, regardless for the gestational age, of 2, 352 +/- 0,623106 microm(2)/ms. We found a significant correlation between ADC and gestational age (Pearson correlation = 0,816). CONCLUSION: The ADC values correlate with gestational age since alveolar fluid secretion and angiogenesis increase gradually. Therefore, ADC can be considered as a new parameter for studying lung maturity.