Prenatal diagnosis of fetal respiratory function: evaluation of fetal lung maturity using lung-to-liver signal intensity ratio at magnetic resonance imaging.

OBJECTIVE: The purpose of this retrospective study is to determine the fetal lung-to-liver signal intensity ratio (LLSIR) on T2-weighted images for the prediction of neonatal respiratory outcome. METHODS: One hundred ten fetuses who underwent magnetic resonance imaging (MRI) examination for various indications after 22 weeks of gestation participated in this study. LLSIR was measured as the ratio of signal intensities of the fetal lung and liver on T2-weighted images at MRI. We examined the changes of the ratio with advancing gestation and the relations between LLSIR and the presence of the severe respiratory disorder (SRD) after birth. The best cut-off value of the LLSIR to predict respiratory outcome after birth was calculated using receiver operating characteristic (ROC) curve analysis. RESULTS: Lung-to-liver signal intensity ratio correlated significantly with advancing gestational age (R = 0.35, p < 0.001). The non-SRD group had higher LLSIR compared with the SRD group (2.15 ± 0.30 vs. 1.53 ± 0.40, p < 0.001). ROC curve analysis showed that fetuses with an LLSIR < 2.00 were more likely to develop SRD [sensitivity: 100%, 95% confidence interval (CI): 52-100%; specificity: 73%, 95% CI 54-88%]. CONCLUSION: The fetal LLSIR on T2-weighted images is an accurate marker to diagnose the fetal lung maturity.

Hemodynamic analysis of cephalothoracopagus by the color doppler method. A comparison to normal fetuses via a longitudinal study.

In a case of cephalothoracopagus, the umbilical artery (UA) was observed with color Doppler method, and the findings were compared with the hemodynamics of 46 normal fetuses. The patient was a 25-year-old primigravida who had appeared for routine prenatal visits since her 6th week of pregnancy. At a later time, the patient was examined after an interval of 4 weeks. Although an ultrasonography was also conducted, unfortunately, any findings of cephalothoracopagus were not detected. In the 25th week of gestation, we hospitalized her for marked polyhydramnios (amniotic fluid index: 280 mm), at which time an ultrasound examination revealed cephalothoracopagus. In the UA, the V(max) was 30.3 cm/s (normal fetus at 25-28 weeks: 33.5 +/- 3.9 cm/s). The UA hemodynamics fell below the normal range. At 26 weeks, the UA V(max) was 56.5 cm/sec, a level which significantly exceeded the normal range. The patient underwent a cesarean section at 27 weeks of gestation; the indication was fetal distress. This is caused by the condition in which the fetal heart beats decreases to 90 beats per minute 3 times during a 10-min period as measured on the cardiotocograms. She delivered a 1,392-gram female with an Apgar score of 2 points (respiratory 1 point and heart rate 1 point). The infant was a cephalothoracopagus, with one head, two hearts, four upper limbs, and four lower limbs. The neonate died from circulatory failure 56 min after birth.