CASE SERIES Case 1A 30-year-old woman was referred at 13 + 1 weeks' gestation for first-trimester screening. The fetus had a crown-rump length (CRL) of 72 mm and a nuchal Figure 1 The mid-sagittal view is the best plane for evaluating intracranial translucency (IT) and the posterior brain region. This ultrasound image in a 13-week fetus illustrates the landmarks typical of a normal examination. The thalamus (Th) and brainstem (BS) have a hypoechoic appearance. The fourth ventricle, also called the IT, appears as an anechoic region with two horizontal echogenic borders, allowing reliable identification: the anterior border of the IT is the posterior border of the BS, and the posterior border of the IT is the choroid plexus (Chor. plex.) of the fourth ventricle. The choroid plexus is a well-recognized structure floating in the fluid of the IT and the future cisterna magna (f.CM), which are still connected to one another. The brainstem-occipital bone distance (BSOB) appears larger than does the brainstem diameter itself. OB, occipital bone. translucency thickness (NT) of 1.7 mm. Routine examination of the posterior brain failed to show the expected normal anatomy (Figure 1) 1,2 ; instead the brainstem appeared thickened and shifted backward toward the occipital bone (Figure 2), such that the ratio of brainstem diameter to brainstem-occipital bone distance (BS/BSOB ratio) was increased 3 , with a value of 1

K E Y W O R D S:congenital heart defects; deletion 22q11; fetal echocardiography; prenatal diagnosis; thymus ABSTRACTObjectives To establish reference ranges for the fetal thymic-thoracic ratio (TT-ratio) and to compare results with those from fetuses with congenital heart defects (CHD) with and without microdeletion 22q11 (del.22q11), a condition known to be associated with a hypoplastic thymus. Methods TT-ratio was defined as the quotient of the anteroposterior thymic to the intrathoracic mediastinal diameters measured in the three vessels and trachea view. This ratio was measured in a prospective

Objectives To assess whether, at 11-13-week and mid-trimester ultrasound

Fetuses with a normal-sized corpus callosum have a rectangular-shaped CSP, with a CSP ratio > 1.5 in the second half of gestation. Most fetuses with pACC have an abnormally shaped, wide and short CSP, with a decreased CSP ratio. This simple ratio has the potential to identify fetuses at high risk for pACC. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Objectives To establish values of fetal left brachiocephalic vein (LBCV) dimensions during normal pregnancy and determine whether routine assessment of the LBCV may help in identifying fetuses with congenital abnormalities of this vessel. Methods