KEY FACTS Terminology • Autosomal trisomy of chromosome 18 (T18) Imaging • Hallmark finding: Multiple anomalies ○ No single anomaly is hallmark of T18 • Most cases with findings at…

KEY FACTS Terminology • Monochorionic (MC) twin complication caused by intrauterine transfusion of blood from donor twin to recipient twin via arteriovenous placental anastomoses Imaging • Hallmark finding is oligohydramnios…

KEY FACTS Imaging • Fetal growth restriction • Brain findings ○ Microcephaly (up to 27%) ○ Ventriculomegaly (moderate to severe in 45%) – Intraventricular adhesions, abnormal periventricular echogenicity – Periventricular/parenchymal…

KEY FACTS Imaging • Germinal matrix hemorrhage (GMH) most common at caudothalamic (CT) groove in vascular germinal matrix • Grading system ○ Grade 1 : GMH only with globular echogenic…

KEY FACTS Imaging • Nonrandom association of 6 core abnormalities ○ V ertebral defects – Hemivertebrae: Best demonstrated in coronal plane, scoliosis originates at hemivertebra(e) – Fusion of vertebral bodies…

KEY FACTS Terminology • Controversial as to etiology, but simplest concept is entrapment of fetal parts by disrupted amnion Imaging • Asymmetric distribution of bizarre “slash” defects is hallmark of…

KEY FACTS Imaging • 1st-trimester findings (11- to 14-week scan) ○ ↑ nuchal translucency: ↑ fluid behind neck on midsagittal view ○ Absent nasal bone ○ Abnormal ductus venosus and…

KEY FACTS Terminology • Marginal cord insertion (MCI) ○ Umbilical cord inserts within 2 cm of placenta edge • Velamentous cord insertion (VCI) ○ Umbilical cord inserts on membranes Imaging…

KEY FACTS Imaging • Biophysical profile (BPP) score : 0 or 2 points for 4 parameters in 30 min; numbers added for BPP score: 0, 2, 4, 6, 8 out…

KEY FACTS Terminology • Cervical insufficiency is clinical diagnosis: Inability of cervix to retain pregnancy in absence of contractions or labor • Short cervix is sonographic observation: Cervical length (CL)…