The changes in magnetic resonance properties of the fetal lungs: a first result and a potential tool for the non-invasive in utero demonstration of fetal lung maturation.

OBJECTIVE

To measure magnetic resonance parameters T1 and T2 of the fetal lungs and investigate the relationship of these parameters to changes in volume and gestation.

DESIGN

Prospective cross-sectional study.

SETTING

Large teaching hospital in Nottingham and the Magnetic Resonance Centre at the University of Nottingham.

POPULATION

Normal pregnancies from 20 weeks to term.

METHODS

T1, T2, and lung volume were measured in the fetus using echo-planar magnetic resonance imaging.

MAIN OUTCOME MEASURES

The relationship of T1 and T2 to gestational age and lung volume.

RESULTS

Linear regression demonstrated a significant relationship (P < 0.001) between gestational age and lung volume, T1 and T2. There was also a significant relationship between lung volume and T1 and T2 (P < 0-001).

CONCLUSIONS

Relaxation time measurements give additional information to lung volume estimation in the assessment of lung physiology in utero. We have demonstrated the progressive changes which take place in the fetal lungs between 20 weeks and term. The physiological changes which can be demonstrated with this non-invasive technique may have an important application in the demonstration of fetal lung maturity in a prospective non-invasive manner.