Three- and four-dimensional HDlive rendering image of fetal acrania/exencephaly in early pregnancy.

We present two cases of fetal acrania/exencephaly reconstructed employing the three- (3D) and four-dimensional (4D) HDlive rendering mode in early gestation. Two fetuses with acrania/exencephaly were studied with the 3D/4D HDlive rendering mode at 13 and 15 weeks, respectively. In Case 1, at 13 weeks' gestation, deformed and degenerated brain tissues were clearly shown using the 3D/4D HDlive rendering mode. In Case 2, at 15 weeks and 6 days of gestation, two amniotic bands and acrania/exencephaly were depicted with the 3D/4D HDlive rendering mode. Fragile brain hemispheres with amniotic bands were rocking with fetal movements. The 3D/4D HDlive rendering mode provides physicians, couples, and their families with important and additional information, and has the potential to supplement two-dimensional and conventional 3D ultrasound in diagnosing fetal acrania/exencephaly.