The "cortical invagination sign": a midtrimester sonographic marker of unilateral cortical focal dysgyria in fetuses with complete agenesis of the corpus callosum.

BACKGROUND: Agenesis of the corpus callosum is associated with several malformations of cortical development. Recently, features of focal cortical dysgyria have been described in fetuses with agenesis of the corpus callosum. OBJECTIVE: This study aimed to describe the "cortical invagination sign," a specific sonographic feature of focal cortical dysgyria, which is consistently seen at midtrimester axial brain ultrasound in fetuses with complete agenesis of the corpus callosum. STUDY DESIGN: This was a retrospective analysis of prospectively collected data from 2018 to 2021, including patients referred to 5 fetal medicine centers in the second trimester of pregnancy (19 0/7 to 22 0/7 weeks of gestation) with suspected complete agenesis of the corpus callosum. All cases with the diagnosis of complete agenesis of the corpus callosum were submitted to an axial sonographic assessment of the fetal brain on the transventricular plane. In this scanning section, the mesial profile of both cerebral hemispheres at the level of the frontal-parietal cortex was investigated. In this area, the operator looked for an abnormal invagination of the cortical surface along the widened interhemispheric fissure, which was referred to as the "cortical invagination sign." All fetuses were submitted to dedicated antenatal magnetic resonance imaging to reassess the ultrasound findings. Cases with additional brain anomalies, which did not involve the cortex, were excluded. The final diagnosis was confirmed at postnatal brain magnetic resonance imaging or postmortem examination, for cases undergoing termination of pregnancy. The primary outcome of this study was to evaluate the presence and laterality of the "cortical invagination sign" in fetuses with complete agenesis of the corpus callosum at antenatal ultrasound and magnetic resonance imaging. RESULTS: During the study period, 64 cases of complete agenesis of the corpus callosum were included; of those cases, 50 (78.1%) resulted in termination of pregnancy, and 14 (21.9%) resulted in a live birth. The "cortical invagination sign" was detected at ultrasound in 13 of 64 cases (20.3%) and at targeted brain magnetic resonance imaging in 2 additional cases (23.4%), all of which were electively terminated. Moreover, the "cortical invagination sign" was found to be exclusively unilateral and on the left cerebral hemisphere in all the cases. There was a predominant number, although nonsignificant, of male fetuses (80.0% of cases; P=.06) in the group of complete agenesis of the corpus callosum with the "cortical invagination sign." CONCLUSION: The "cortical invagination sign" is a specific marker of focal cortical dysgyria, which seems to characterize at midtrimester of pregnancy in a large group of fetuses with complete agenesis of the corpus callosum. The etiology, pathophysiology, and prognostic significance of this finding remain to be elucidated.

Dilated intracranial translucency and Blake's pouch cyst: first-trimester ultrasound markers of occipital cephalocele diagnosed using novel three-dimensional reslicing technique.

Abnormal intracranial translucency (IT) (fourth ventricle) and a Blake's pouch cyst with normal brain stem cavity may be valuable first-trimester call signs of defects in the skull base. Here, we report a case of presumptive two-dimensional sonographic diagnosis of occipital cephalocele that was posed at the time of 11-13 weeks aneuploidy scan. The two-dimensional sonographic finding elicited a detailed fetal neuroscan that was performed using either multiplanar mode or a novel three-dimensional reslicing and lightening technique. The use of three-dimensional sonographic software and offline "navigation" within the volume of interest enabled operators to capture a diagnostic snapshot of the condition, enhancing quality imaging and early detection of the encephalic lesion.

Ultrasound diagnosis of central nervous system anomalies (bifid choroid plexus, ventriculomegaly, Dandy-Walker malformation) associated with multicystic dysplastic kidney disease in a trisomy 9 fetus: case report with literature review.

Trisomy 9 is a lethal chromosomal abnormality that rarely progresses beyond the second trimester of pregnancy. Multiple central nervous system anomalies, including bifid choroid plexus, ventriculomegaly, and Dandy-Walker malformation, associated with multicystic dysplastic kidney disease in a trisomy 9 fetus are reported. The prenatal ultrasound diagnosis has been aided by novel three-dimensional ultrasound software.

Fetal lower urinary tract obstruction and its management.

INTRODUCTION: Prenatal counselling in case of fetal obstructive uropathies still represents a clinical dilemma, despite ultrasound detection of lower urinary tract obstruction has greatly advanced during recent years as well as fetal intervention techniques. MATERIALS AND METHODS: A systematic review of the relevant literature on the topic was performed, with a special focus on the role of antenatal ultrasound, in utero treatment and prognosis. CONCLUSIONS: A clinico-diagnostic flow chart was developed, with the specific aim of aiding health care givers in the clinical management and the parental decision-making process.