Diagnosis of fetal cortical abnormalities by new reference charts for assessment of sylvian fissure biometry.

OBJECTIVE: To develop novel fetal reference ranges for the characterization of the normal appearance of the Sylvian fissures (SF) along gestation and to apply them to fetuses with cortical abnormalities affecting the SF. METHODS: In this cross-sectional study, we used three-dimensional sonographic multiplanar reformatting (3D-MPR) to examine the fetal SF. Normal development was assessed in the second and third trimesters. SF parameters were evaluated in predefined axial and coronal planes: insular height and length, SF depth, and the extent of the coverage of the insula by the frontal and temporal lobes. Intra-observer variability and inter-rater reliability for the studied parameters were evaluated. The new reference charts were applied to 19 fetuses with cortical abnormalities involving the SF who had appropriate sonographic volumes for 3D-MPR analysis. Their diagnoses were confirmed by autopsy, fetal or postnatal MRI, genetic findings related to cortical malformations, or an abnormal cortical imaging pattern with similar MRI findings in an affected sibling. We applied the two previously published references for the evaluation of fetal SF development to these cases and compared the ability of the references to correctly detect SF abnormalities. RESULTS: The study included 189 fetuses of low-risk singleton pregnancies between 24 and 34 gestational weeks. The insular length or height increased with gestational age in the axial and coronal planes with adjusted R2  = 0.621, p < 0.0001 and R2  = 0.384, p < 0.0001, respectively. The SF depth also increased with gestational age in the axial and coronal planes with adjusted R2  = 0.695, p < 0.0001 and R2  = 0.219, p = 0.008, respectively. The extent of the coverage of the insula by the frontal and temporal lobes in the coronal plane increased with gestational age (adjusted R2  = 0.627, p < 0.0001 and R2  = 0.589, p < 0.0001, respectively). The interclass correlation coefficients of the intra- and inter-rater reliability of the studied parameters ranged between 0.71 and 0.97. The cortical anomalies in the 19 fetuses were polymicrogyria (7), simplified gyral pattern (3), dysgyria (3), lissencephaly (2), cortical malformation related to tubulinopathy (1), brain atrophy (1), cortical dysplasia (1), and cobblestone malformation (1). Three of the fetuses had multiple cortical anomalies. In 17 of 19 (89%) cases, at least one of our 6 SF parameters was found to be out of the normal range. In the coronal plane, SF height and depth were measured below 2SD in 9 (47%) and 4 (21%) cases, respectively. In the axial plane, SF length and depth were out of the normal ranges in six (31.5%) and four (21%), correspondingly. In the coronal plane, the opercular coverage by the frontal and temporal lobes was below 2 SD in 10 (52%) and 11 (57%), respectively. The scoring of the SF operculization by Quarello et al. was abnormal in 8 cases (42%). The measurement of the SF angle according to Poon et al. was abnormal in 14 cases (74%). CONCLUSIONS: The fetal SF is a complex developing structure that can be reliably characterized by sonographic parameters. One abnormal parameter is sufficient to raise the suspicion of SF malformation. Our new SF parameters might facilitate the detection of prenatal cortical abnormalities affecting the SF.

Periventricular pseudocysts of noninfectious origin: Prenatal associated findings and prognostic factors.

OBJECTIVE: The purpose of this study was to establish prognostic factors in fetuses diagnosed with periventricular pseudocysts (PVPCs) without known congenital infection, between 28 and 37 weeks of gestation. METHODS: This retrospective study included cases of fetal PVPC from 2008 to 2018. PVPCs were classified according to location, number, extension, morphology, and size. Additional findings, MRI and genetic studies were recorded. Pregnancy outcome, postnatal, or postmortem results were obtained. Images from patients with normal (Group 1) and abnormal postnatal development (Group 2) were compared for analysis of factors predictive of outcome. RESULTS: One-hundred and fifteen pseudocysts were observed in 59 patients. In 34 fetuses (57%), the PVPC was an isolated finding. Thirty-nine patients delivered live newborns, 27% opted for termination of pregnancy, and 4 patients were lost to follow-up. Eighty-four percent of the liveborns had normal development. When assessing for the influence of pseudocyst characteristics, a wide CSP, or large head circumference, neither of these affected the outcome. The presence of additional anomalies was the only positive predictor for abnormal development regradless of specific PVPC characteristics (P = .002). CONCLUSIONS: In fetuses with PVPCs, the presence of additional anomalies was the only predictor for adverse postnatal outcome. No association between cystic characteristics and adverse outcome was observed.

The cerebellar "tilted telephone receiver sign" enables prenatal diagnosis of PHACES syndrome.

OBJECTIVES: To describe a unique posterior fossa neuroimaging characteristic of prenatal PHACES syndrome (PS): unilateral cerebellar hypoplasia (UCH) and ipsilateral posterior fossa (PF) cyst communicating with an asymmetrically distended 4th ventricle. METHODS: The registries of seven prenatal diagnosis centers were searched for cases with PF findings and a postnatal diagnosis of PS. All records were evaluated for ultrasound and MRI findings and the postnatal outcome. PS was diagnosed after birth according to the consensus statement on diagnostic criteria for PS from 2009. The imaging findings of the PS fetuses were compared to a group of consecutive cases with fetal UCH, whose postnatal diagnosis was not PS. RESULTS: The PS group included 10 fetuses. All were referred due to UCH accompanied by an ipsilateral retrocerebellar cyst. All pregnancies resulted in livebirths, all newborns had a large segmental facial hemangioma. In all PS fetuses the affected cerebellar hemisphere was upwardly displaced by an ipsilateral PF cyst communicating with an asymmetrically distended 4th ventricle. An upwardly rotated and deviated vermis merged with the contralateral cerebellar peduncles forming an elongated oblique connection between the cerebellar hemispheres, resulting in a unique cerebellar shape, "a tilted telephone receiver sign" (TTRS), on the coronal plane through the upper vermis.The non-PS group included 11 fetuses with UCH: clastic cerebellar lesions (8) and a unilateral PF arachnoid cyst (3). The TTRS was not depicted in any of them (p < 0.0005). CONCLUSIONS: The cerebellar TTRS is a specific fetal imaging feature of PHACES syndrome enabling its prenatal diagnosis.

Walker-Warburg syndrome and tectocerebellar dysraphia: A novel association caused by a homozygous DAG1 mutation.

OBJECTIVES: To elaborate the imaging phenotype associated with a homozygous c.743C > del frameshift mutation in DAG1 leading to complete absence of both α- and ß-dystroglycan previously reported in a consanguineous Israeli-Arab family. METHODS: We analyzed prenatal and postnatal imaging data of patients from a consanguineous Israeli-Arab kindred harboring the DAG1 mutation. RESULTS: The imaging studies (fetal ultrasound, CT scan and postnatal MRI) demonstrated: flat cortex (abnormally thick with irregular pebbled cortical-white matter border on MRI), hydrocephalus, scattered small periventricular heterotopia and subependymal hemorrhages and calcifications, z-shaped brainstem, and in addition an occipital encephalocele, vermian agenesis, and an elongated and thick tectum (tectocerebellar dysraphia). CONCLUSIONS: The novel association of cobblestone malformation with tectocerebellar dysraphia as part of WWS is characteristic of the homozygous c.743C > del frameshift mutation in the DAG1 gene.

Unique Imaging Features Enabling the Prenatal Diagnosis of Developmental Venous Anomalies: A Persistent Echogenic Brain Lesion Drained by a Collecting Vein in Contrast with Normal Brain Parenchyma on MRI.

OBJECTIVE: To describe the prenatal imaging features enabling diagnosis of developmental venous anomalies (DVA). METHODS: Four fetuses with unexplained persistent echogenic parenchymal brain lesions were studied. The evaluation included dedicated neurosonography, fetal MRI, serology for intrauterine infection, screening for coagulation abnormalities, and chromosomal microarray. Postnatal neurodevelopmental follow-up or autopsy results were assessed. RESULTS: DVA presented as very slowly growing echogenic brain lesions without cystic components, calcifications, or structural changes on otherwise normal neurosonographic scans performed at 2- to 3-week intervals. A specific Doppler feature was a collecting vein draining the echogenic parenchyma. Fetal brain MRI depicted normal anatomy on half-Fourier acquisition single-shot turbo spin-echo and diffusion-weighted imaging. The rest of the evaluation was normal. CONCLUSIONS: In cases with a persistent, parenchymal echogenic lesion without clastic or structural changes, DVA should be considered. Demonstration of a collecting vein draining the lesion and normal brain anatomy on MRI confirm the diagnosis.