Pedro Teixeira Castro

Objectives: To determine gestational age-specific reference ranges and develop a Z-score equation for the fetal ductal pulsatility index (PI), between 24 and 33 + 6 weeks of gestation. Methods: A prospective cross-sectional study conducted from 2023 to 2024, 226 singleton fetuses between 24 and 33 + 6 weeks were enrolled. The ductus arteriosus (DA) was assessed in the longitudinal plane of the fetus using color Doppler to confirm its course and flow direction, and pulsed Doppler sampling was placed at the proximal DA with an insonation angle 0.90). Conclusions: We established gestational age-specific reference ranges and a Z-score equation for the ductal PI in normal fetuses between 24 and 33 + 6 weeks. These findings provide a standardized tool for fetal cardiologists to identify subtle ductal flow abnormalities and support perinatal risk stratification.

We describe a case report of prenatal presentation of membranous aplasia cutis congenita on the vertex by magnetic resonance imaging, the conflict between the prenatal presentation, the postnatal features, and the long-term follow-up.

Congenital cystic malformations of the posterior cranial fossa encompass Dandy–Walker malformation, Blake's pouch cyst, and arachnoid cyst, which are usually associated with increased cerebrospinal fluid in the posterior fossa. Although isolated cerebellar vermis hypoplasia courses with a normal posterior fossa volume and is not associated with a cyst, the smaller volume of the cerebellar vermis results in a relative increase in cerebrospinal fluid compared to the posterior fossa volume and is considered a differential diagnosis. Furthermore, mega cisterna magna, which is an anatomical variant, is also a differential diagnosis of these congenital malformations. Usually, these malformations are diagnosed through screening prenatal ultrasound. However, fetal magnetic resonance imaging (MRI) can confirm, change, or complement questionable findings and identify associated malformations. Therefore, fetal MRI plays an essential role in evaluating fetuses with suspected brain malformations. Manual MRI segmentation can facilitate the understanding of these congenital cystic posterior fossa malformations. Three‐dimensional (3D) segmentation offers a spatial view of the abnormalities, as well as their relationships with adjacent anatomical structures, allowing a better multidisciplinary team approach. The aim of this article is to review the embryology of the posterior cranial fossa, discuss the fetal MRI protocol to evaluate the cystic posterior fossa malformations, and to illustrate the key MRI features of these malformations.