To prospectively determine apparent diffusion coefficient (ADC) values of normally developing fetal lungs over gestation, as obtained by diffusion-weighted (DW) magnetic resonance imaging (MRI) and to investigate its potential application in fetuses with congenital diaphragmatic hernia (CDH).
Informed consent was obtained for this cross-sectional study of 93 fetuses with normal lungs and 14 with isolated left-sided CDH, assessed between 18 and 40 weeks of gestation. MRI delineation of left and right lungs was performed on the native DW image, b0, and three values of ADC, corresponding to the overall value (ADCavg), and values for low and high values of b (ADClow and ADChigh, respectively) were calculated. Regression analysis was used to assess the relationship between gestational age and b0-values as well as calculated ADC values. The b0 and ADC values of normal and CDH fetuses were compared with normal ranges using the Mann–Whitney U-test.
In fetuses with normal lungs, there was a negative correlation between gestational age and b0 values as well as with ADChigh, a positive correlation with ADClow but no correlation with ADCavg. When measurable, ADChigh values were lower in CDH as compared to fetuses with normal lungs and ADClow values were higher. ADClow was unrelated to lung volume.
There is a significant relationship between ADClow and ADChigh values and gestational age in normal fetal lungs. This relationship is most probably explained by developmental changes during the last three stages of lung development, which involve intense peripheral growth of airways and vessels as well as maturation. In CDH, measurement of ADClow might be useful as a predictor of postnatal outcome that is independent of lung volume. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.