Prenatal diagnosis of amniotic sheets by magnetic resonance imaging.

We report prenatal diagnosis of an amniotic sheet by magnetic resonance imaging (MRI) at 28 weeks' gestation. The amniotic sheet divided the uterine cavity into 2 compartments, with the fetus and placenta located in the upper portion of the amniotic cavity. Although prenatal diagnosis of amniotic sheets can be performed with ultrasonography, the wider field of view and excellent tissue contrast provided by MRI may allow better spatial visualization of the amniotic sheet and, therefore, improve the diagnostic accuracy.