Magnetic resonance imaging of fetuses with intracranial defects.

Thirteen women whose fetuses had intracranial defects on ultrasound examination were offered magnetic resonance imaging (MRI) without charge. All fetuses were paralyzed with pancuronium before the study, which lasted approximately 1 hour. With the mother in the left lateral decubitus position to minimize transmitted maternal aortic pulsation, T1-weighted images were obtained using a Picker 0.5-tesla superconductive unit. Magnetic resonance imaging provided excellent detail of intracranial anatomy in all cases. In four of the 13 fetuses, the MRI diagnosis differed from that of ultrasound and ultimately proved correct. In another three, MRI added greatly to the ultrasound diagnosis by delineating intracranial anatomy more precisely. In the remaining six cases, MRI confirmed the ultrasound impression. For circumstances in which the ultrasound diagnosis is unclear or antenatal intervention might require exact knowledge of anatomical detail, the additional information provided by MRI may justify its cost.

Magnetic resonance imaging of anomalous fetuses.

Magnetic resonance imaging (MRI) has been used sparingly in obstetrics. The reasons for this relate mainly to cost, availability, difficulty obtaining clear images because of fetal movement, and the convenience and utility of ultrasound. However, MRI use is expanding and has the potential to play an important role in selected problem pregnancies. We studied the pregnancies of five women whose fetuses showed anomalies by ultrasound. These included cases of a large body wall defect, a diaphragmatic hernia, hydrocephalus, Meckel-Gruber syndrome, and iniencephaly with a diaphragmatic hernia (the iniencephaly sequence). Three of these examinations followed fetal neuromuscular blockade, and two were associated with oligohydramnios without fetal paralysis. Paralysis provided superior images. The fetal central nervous system, subcutaneous tissue, and liver imaged particularly well. This study illustrates that MRI can enhance and even clarify certain information provided by ultrasound.

Normal values for human umbilical venous and amniotic fluid pressures and their alteration by fetal disease.

Umbilical venous and amniotic fluid pressures were measured in 68 human pregnancies at the time that cordocentesis was performed. Normal umbilical venous pressure was unrelated to gestational age and remained within a tight range (5.3 +/- 2.3 mm Hg, mean +/- SD). Fetuses with an elevated umbilical venous pressure had disorders consistent with either hepatomegaly or congestive heart failure. Umbilical venous pressure was significantly increased before treatment in two fetuses with immune hydrops; it rapidly declined with treatment. Neither gestational age nor umbilical venous pressure was significantly different in the groups that received and did not receive pancuronium. There was a strong relationship between amniotic fluid pressure and gestational age in normal pregnancy (r = 0.54, p less than 0.0001). Women with hydramnios had amniotic fluid pressures greater than control subjects (p = 0.0007). This investigation documents normal human amniotic fluid and fetal umbilical venous pressures. These measurements are altered by disease and may prove to be of diagnostic and therapeutic value in the future.