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Microcephaly with simplified gyral pattern (MSG) is an intrinsic genetic central nervous system disorder, characterized by microcephaly (a reduction of brain volume) and a simplified gyral pattern (a reduced number of gyri and shallow sulci associated with normal cortical thickness and neuroanatomical architecture), related to a reduced number of neuronal progenitors in the germinal matrix. We report the first prenatal series of MSG and define the prenatal imaging pattern, which should inform diagnosis and guide prenatal counseling in cases of fetal microcephaly. In this single‐center retrospective study of fetuses with MSG, we assessed features on ultrasound and magnetic resonance imaging (MRI), as well as genetic and neuropathological/postnatal data. We included eight patients who had been referred following observation of microcephaly. Ultrasound examination confirmed microcephaly, with a mean growth delay in head circumference of 3.4 weeks, associated with both a lack of gyration and a lack of opercularization of the Sylvian fissure and without any extracephalic anomaly. Fetal brain MRI confirmed lack of gyration with normal cortical thickness and normal intensity of the white matter in all cases. These MRI features led to exclusion of migration/corticogenesis disorders (lissencephaly/polymicrogyria), instead suggesting MSG. The posterior fossa was normal in seven of the eight cases. The corpus callosum was thin in four cases, hypoplastic in two and dysgenetic in two. In four cases, the pregnancy was terminated. The diagnosis of MSG was confirmed from neuropathological and postnatal MRI data. MSG was associated with a genetic diagnosis of RTTN (n = 1) and ASPM (n = 2) biallelic variants in three of the six cases in which genetic work‐up was performed. Mild or moderate intellectual deficit with speech delay was present in the three surviving children who were at least 5 years of age at their last examination, without seizures. In conclusion, in the presence of isolated fetal microcephaly with lack of gyration on ultrasound, fetal cerebral MRI is key to diagnosing MSG, which, in the majority of cases, affects the supratentorial space exclusively, and to ruling out other cortical malformations that show a similar sonographic pattern. In addition to imaging, genetic assessment may guide prenatal counseling, since the prenatal prognosis of MSG is different from that of both diffuse polymicrogyria and lissencephaly. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology. [ABSTRACT FROM AUTHOR]

DATA AVAILABILITY STATEMENT Data available on request from the authors GRAPH: Videoclip S1 Transabdominal sagittal grayscale sonography of the thorax, showing a large cyst and a significantly enlarged and hyperechoic right lung, most likely due to compression of the right main bronchus. The right lung () is hyperintense compared with the left one, most likely due to compression of the right main bronchus. gl Although IFDC is a well-known type of mediastinal cyst, an IFDC of this size is rare5. Intrathoracic foregut duplication cysts (IFDC), associated with incomplete recanalization or abnormal budding of the primitive foregut, represent approximately 10% of all mediastinal lesions1,2. [Extracted from the article]

Objectives: To describe clinical and molecular findings in a French multicenter cohort of fetuses with prenatal diagnosis of congenital abnormality and suspicion of a localized overgrowth disorder (LOD) suggestive of genetic variants in the PI3K‐AKT‐mTOR signaling pathway. Methods: We analyzed retrospectively data obtained between 1 January 2013 and 1 May 2020 from fetuses with brain and/or limb overgrowth referred for molecular diagnosis of PI3K‐AKT‐mTOR pathway genes by next‐generation sequencing (NGS) using pathological tissue obtained by fetal autopsy. We also assessed the diagnostic yield of amniotic fluid. Results: During the study period, 21 subjects with LOD suspected of being secondary to a genetic variant of the PI3K‐AKT‐mTOR pathway were referred for analysis. Of these, 17 fetuses had brain overgrowth, including six with isolated megalencephaly (MEG) and 11 with hemimegalencephaly (HMEG). Of the six with MEG, germline variants were identified in four cases, in either PIK3R2, AKT3 or MTOR, and a postzygotic PIK3R2 variant was found in the other two cases. Of the 11 with HMEG, a postzygotic PIK3CA variant was found in three fetuses with extracerebral features of PIK3CA‐related overgrowth spectrum, and in seven fetuses with isolated HMEG. No pathogenic variant was identified in the 11th case with HMEG. Four fetuses with limb overgrowth also had one or more lymphatic malformations (LM) and harbored a postzygotic PIK3CA variant. NGS on cultured amniocytes performed in 10 cases, of which nine had been found positive on analysis of pathological fetal tissue, showed variants in four, in either PIK3CA, PIK3R2 or AKT3. Conclusions: Isolated MEG or HMEG may lead to identification of genetic variants in the PI3K‐AKT‐mTOR signaling pathway. Cases of limb overgrowth and LM or isolated HMEG are likely associated with PIK3CA variants. © 2021 International Society of Ultrasound in Obstetrics and Gynecology. [ABSTRACT FROM AUTHOR]

MRI examination confirmed ultrasound findings, showing superficial implantation of the mass in the posterior perineum, not extending to the anal sphincters posteriorly or the labioscrotal folds anteriorly, with hyperintense fatty component on T1-weighted sequences (Figure 1h,i). Congenital perineal lipoma (CPL) has been reported in approximately 50 cases in the literature published in English1. [Extracted from the article]

To illustrate the prenatal cerebral imaging features associated with tubulinopathy, we report on five affected fetuses from unrelated families, with a de-novo heterozygous variant in a tubulin gene (TUBA1A, TUBB2B or TUBB3). We identified two distinct prenatal imaging patterns related to tubulinopathy: a severe form, characterized by enlarged germinal matrices, microlissencephaly and a kinked brainstem; and a mild form which has not been reported previously in the prenatal literature. The latter form is associated with non-specific features, including an asymmetric brainstem, corpus callosal dysgenesis, a lack of Sylvian fissure operculization and distortion of the anterior part of the interhemispheric fissure with subsequent impacted medial borders of the frontal lobes, the combination of which, in the absence of additional extracerebral anomalies, is highly suggestive of tubulinopathy. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

Linked article: This Correspondence comments on Di Mascio et al. Click here to view the article. [ABSTRACT FROM AUTHOR]

A case study of a 10-year-old male patient with who was diagnosed with variation in the SHH gene leading to microcephaly, intellectual disability, and familial coloboma. The article discusses the diagnosis of the disease with the application of DNA sequencing with the use of Sanger sequencing, use of magnetic resonance imaging (MRI), and phenotype of the patient.

The article presents case studies of two women with polyhydramnios and fetal cardiomegaly. Also includes risk of parenchymal ischemic lesions with vein of Galen aneurysmal malformation (VGAM), and diagnosis of capillary malformation-arteriovenous malformation (CM-AVM) syndrome through Doppler ultrasound.

We report the first series of cases of pericallosal curvilinear lipoma (CL) diagnosed prenatally and highlight the limitations in identifying a specific prenatal imaging pattern using ultrasound and magnetic resonance imaging (MRI). In all five of our cases, on ultrasound, the main feature leading to referral was a short corpus callosum. This subtle callosal dysgenesis was associated with a band of hyperechogenicity surrounding the corpus callosum, mimicking the pericallosal sulcus, which increased in size during the third trimester in three of the four cases in which sonographic follow-up was performed. On T2-weighted MRI, this band showed typical hypointensity in all cases; in contrast, on T1-weighted imaging, in only one case was there hyperintensity, suggestive of fat, as seen typically in the postnatal period. For appropriate prenatal counseling regarding outcome, it is important to identify or rule out CL when mild corpus callosal dysgenesis is observed. One should be aware of subtle diagnostic findings, such as a thin band of echogenicity surrounding the corpus callosum that is seen as a band of hypointensity on T2-weighted fetal MRI, and which may increase in size during gestation. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

We report a case of misinterpretation of decreased apparent diffusion coefficient (ADC) on diffusion-weighted fetal MR, interpreted as a vascular clastic lesion of the posterior fossa, which turned to be caused by an embryonic hypercellular tumour. This article is protected by copyright. All rights reserved. [ABSTRACT FROM AUTHOR]

The authors describes tools that can be used in elucidating cases of unexplained isolated decrease in cephalic biometry. They discusses the importance of understanding the clinical context of unexplained ventriculomegaly, determining the severity of decreased cephalic biometry and analyzing the pericerebral space. They also highlight the need for a systematic analysis of the central nervous system in cases of unexplained decreased cephalic biometry.

We report a specific sonographic cerebral pattern of cobblestone lissencephaly (CL) that has not been described previously. This pattern was encountered in four index cases and allowed prenatal diagnosis of CL associated with Walker-Warburg syndrome. The pattern included both an outer echogenic band with reduced pericerebral space, corresponding to an infra- and supratentorial extracortical layer of neuroglial overmigration on pathological examination, and a 'Z'-shaped appearance of the brainstem. This pattern was found as early as 14 weeks' gestation in one of our cases. [ABSTRACT FROM AUTHOR]

In HMEG, a postzygotic I PIK3CA i variant was found in 3 fetuses with extra-cerebral features of I PIK3CA i -related overgrowth spectrum (PROS), and in 7 fetuses with "isolated HMEG". To describe clinical and molecular findings in fetuses with localised overgrowth disorders (LOD) involving the brain (BO) and/or a limb (LO) diagnosed on prenatal imaging (ultrasonography or MRI), suggesting involvement of the PI3K-AKT-mTOR signalling pathway. OC18.04: Clinical and molecular data in case of prenatal localised overgrowth disorders: major implication of variants in the PI3K-AKT-mTOR signalling pathway. [Extracted from the article]

An abstract of the article "Prenatal imaging cerebral pattern of Cobblestone lissencephaly according to gestational age and imaging modalities ( US, MRI)" by L. Guibaud and others is presented.

The authors reflects on the etiological diagnostic tools to elucidate ventriculomegaly. They provide an overview about ventriculomegaly, considered the common abnormal finding that leads to a diagnosis of fetal central nervous system (CNS) pathology. Also tackled are the tools for complete analysis of the ventricular system following identification of ventriculomegaly.

A letter to the editor is presented in response to the article "Prenatal diagnosis of multiple cortical and deep cerebral vein thromboses in the absence of dural venous malformation" by N. Winer in the 2008 issue.

ABSTRACT Objective To define imaging patterns of unilateral cerebellar hypoplasia ( UCH), discuss possible pathophysiological mechanisms and underline the etiology and prognosis associated with these lesions. Methods In this retrospective study we reviewed the charts of 26 fetuses diagnosed between 2003 and 2011 with UCH, defined by asymmetrical cerebellar hemispheres with or without decreased transverse cerebellar diameter. The review included analysis of the anatomy of the cerebellar hemispheres, including foliation, borders and parenchymal echogenicity, and of the severity of the hypoplasia. Data from clinical and biological work-up and follow-up were obtained. Results Our series could be divided into two groups according to whether imaging features changed progressively or remained constant during follow-up. In Group 1 ( n = 8), the progression of imaging features, echogenic cerebellar changes and/or hyposignal in T2*-weighted MR images were highly suggestive of ischemic/hemorrhagic insult. In Group 2 ( n = 18), imaging features remained constant during follow-up; UCH was associated with abnormal foliation in three proven cases of clastic lesions, a cystic lesion was noted in three cases of PHACE (posterior fossa anomalies, hemangioma, arterial anomalies, cardiac abnormalities/aortic coarctation, eye abnormalities) syndrome and, in the remaining cases, UCH remained unchanged, with no imaging pattern typical of hemorrhage. In 24 cases the infant was liveborn and follow-up was continued in 23, for a mean period of 3 years. Among these, neurological complications were identified in seven (in one of seven (at a mean of 46 months) in Group 1 and in six of 16 (at a mean of 35 months) in Group 2). The surface loss of cerebellar hemisphere was > 50% in 19/24 fetuses and the vermis was clearly normal in appearance in 19/24. Predisposing factors for fetal vascular insult were identified in eight cases: these included maternal alcohol addiction, diabetes mellitus, congenital cytomegalovirus infection and pathological placenta with thrombotic vasculopathy and infarctions. Conclusion UCH is defined as a focal lesion of the cerebellum that may be secondary to hemorrhage and/or ischemic insult, suggesting a clastic origin, particularly when imaging follow-up reveals changes over time. UCH may also be a clue for the prenatal diagnosis of PHACE syndrome. The amount of surface loss of cerebellar hemisphere does not correlate with poor prognosis. UCH with normal vermis is often associated with normal outcome. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT In order to illustrate the significance of a new anatomical finding, distortion of the interhemispheric fissure ( DIHF) associated with impacted medial borders of the frontal lobes, we report a retrospective observational study of 13 fetuses in which DIHF was identified on prenatal imaging. In 10 cases there were associated anatomical anomalies, including mainly midline anomalies (syntelencephaly (n = 2), lobar holoprosencephaly (n = 1), Aicardi syndrome (n = 2)), but also schizencephaly (n = 1), cortical dysplasia (n = 1) and more complex cerebral malformations (n = 3), including neural tube defect in two cases. Chromosomal anomaly was identified in two cases, including 6p deletion in a case without associated central nervous system anomalies and a complex mosaicism in one of the cases with syntelencephaly. In two cases, the finding was apparently isolated on both pre- and postnatal imaging, and the children were doing well at follow-up, aged 4 and 5 years. The presence of DIHF on prenatal imaging may help in the diagnosis of cerebral anomalies, especially those involving the midline. If DIHF is apparently isolated on prenatal ultrasound, magnetic resonance imaging is recommended for careful analysis of gyration and midline, especially optic and olfactory structures. Karyotyping is also recommended. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd [ABSTRACT FROM AUTHOR]

Joubert syndrome and related disorders (JSRD) are characterized by absence or underdevelopment of the cerebellar vermis and a malformed brainstem. This family of disorders is a member of an emerging class of diseases called ciliopathies. We describe the abnormal features of the brain, particularly the fourth ventricle, in seven fetuses affected by JSRD. In three cases abnormality of the fourth ventricle was isolated and in four cases there were associated malformations. The molar tooth sign (MTS) was always present and visible on two-dimensional ultrasound and, when performed, on three-dimensional ultrasound and magnetic resonance imaging. The fourth ventricle was always abnormal, in both axial and sagittal views, presenting pathognomonic deformities. It is important to identify JSRD, preferably prenatally or at least postnatally, due to its high risk of recurrence of about 25%. A detailed prenatal assessment of the fourth ventricle in several views may help to achieve this goal. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented that discusses agenesis of the corpus callosum with interhemispheric cyst, linked with deviant cortical sulci near cystic structure, without any hidden cortical dysplasia.

ABSTRACT By review of a series of cases, we set out to identify sonographic features suggestive of an obstructive mechanism in second-trimester fetuses with ventriculomegaly and describe developmental disorders related to pathological differentiation of the diencephalon, mesencephalon and rhombencephalon that lead to obstruction of cerebrospinal fluid flow. We studied retrospectively 11 fetuses referred for severe second-trimester ventriculomegaly of undetermined origin. Neurosonography was performed with detailed analysis of the third ventricle, thalami, cerebral aqueduct and cerebellum. The cerebral imaging data were compared with neuropathological data in eight patients, with a focus on the level and etiology of the obstruction. Parenchymal thinning and reduction of the pericerebral spaces were highly suggestive of ventriculomegaly due to an obstructive mechanism. The ventriculomegaly was related to diencephalosynapsis (thalamic fusion and third ventricle atresia) in five cases and partial/complete aqueduct stenosis in six; it was associated with cerebellar hypoplasia in six cases, including rhombencephalosynapsis in two cases. In nine patients, disorders of the diencephalon, mesencephalon and rhombencephalon were present. In cases of severe isolated ventriculomegaly in which sonographic features are suggestive of an obstructive mechanism, close examination of the third ventricle, thalami, aqueduct of Sylvius and cerebellum may reveal pathological differentiation of the diencephalon, mesencephalon or rhombencephalon, often in combination. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

Objectives To construct reference ranges for fetal optic tractmean diameter and to reportmeasurements in fetuses with agenesis of the septum pellucidum (SP). Methods Three-dimensional volumes of the optic chiasm were acquired in 98 normal fetuses during routine sonographic examination at 21-36 weeks' gestation and the diameters of the posterior left and right optic tracts were measured offline. A polynomial regression approach (mean and SD model) was used to compute reference charts for the mean fetal optic tract diameter measurements. In addition, 23 volumes were acquired in fetuses with SP agenesis for offline measurement of optic tract diameter. Complete follow-up was obtained in 13 of these 23 cases. Results In normal fetuses, the optic tract diameter increased linearly throughout gestation. There was no evidence of increased variability with gestational age (constant SD). Normal charts and equations for Zscore calculation were constructed. Among the 13 fetuses with SP agenesis and complete follow-up, nine had normal measurements, of which eight had normal vision postnatally. Four had hypoplastic optic tract, defined as mean optic tract diameter Z-score below -3. Of these, two underwent termination of pregnancy and pathological examination confirmed hypoplasia of the tract, one showed signs of hypoplasia at magnetic resonance imaging and postnatal examination confirmed blindness, and one had a hypoplastic measurement for only one tract and was born with poor vision and abnormal bilateral eye movements. Conclusion We present new reference charts for mean fetal optic tract diameter. In fetuses with agenesis of the SP, sonography of the optic tract might be a useful tool to assess its development and may help in prenatal counseling. [ABSTRACT FROM AUTHOR]

In this article the author discusses the standardization in diagnosing fetal cerebral ventriculomegaly through fetal cerebral ventricular measurement. He believes in the study conducted by Melchiorre K. et al. that the real challenge is the establishment of diagnosing standards to avoid errors. He proposes the use of an image-scoring method divided into 3 primary criteria and 2 secondary criteria based in the study for sonographic ventricular measurement. The criteria are likewise discussed.

The article examines fetuses at 24-34 weeks in which prenatal Sylvian fissure development was identified on prenatal cerebral imaging. The imaging data were correlated to macro- and microscopic neuropathological data or to postnatal clinical and imaging findings. According to the authors, abnormal operculization does not systematically reflect underlying cortical dysplasia and it may be related to extracorticol factors such as abnormal cerebral volume.

The article examines a subjective and reproducible method for Sylvian fissure operculization (SFO) assessment between 22 and 32 weeks of pregnancy. According to the authors, the inter- and intraobserver agreement correlation coefficients were 0.91 and 0.95, respectively, with a standard error of measurement <1 scoring unit, which corresponds to an accuracy of within one week.

The article discusses two cases of rapidly involuting congenital hemangioma (RICH) of the skull diagnosed in the third trimester of gestation. Ultrasound examination showed a soft tissue vascular mass of the skull with a specific sonographic finding, a thin hyperechogenic line over the lesion and continuous with the calvaria. In each case, the diagnosis of RICH was confirmed by demonstrating a decrease in reduction in the size of the tumor and regression of the vascular component.

The article discusses several reports published within the issue, including one on the use of two- and three-dimensional ultrasound for anatomical approach to fetal posterior fossa and another on the classification of abnormalities which include agenesis, hypoplasia and atrophy.

Objectives To investigate the correlation between fetal lung volume (FLV), measured with magnetic resonance imaging (MRI), and postnatal mortality in newborns with prenatally diagnosed isolated congenital diaphragmatic hernia (CDH). Methods In a 4-year prospective multi center study, 77 fetuses with isolated CDH diagnosed between 20 and 33 necks' gestation underwent fast spin-echo T2- weighted lung MRI. These MRI-FLV measurements were compared with a previously published normative curve obtained in 215 fetuses without thoracoabdominal malformations and with normal ultrasound biometric findings. FLV measurements were correlated with postnatal survival. The mean gestational age at MRI was 31.3 weeks. Results The measured/expected FLV ratio was significantly lower in the newborns with CDH who died compared with those who survived (23.6 ± 12.2 vs. 36.1 ± 13.0, P < 0.001). When the ratio was below 25%, there was a significant decrease in postnatal survival (19% vs. 40.3%, P = 0.008). Survival was significantly lower for neonates when one lung could not be seen by fetal MRI compared with those fetuses with two visible lungs on MRI (17.9% vs. 62.1%, P < 0.001). Conclusion In isolated CDH, FLV measurement by MRI is a good predictor of postnatal mortality due to pulmonary hypoplasia. [ABSTRACT FROM AUTHOR]

Objectives: To describe an antenatal sonographic renal pattern encountered in Bardet-Biedl syndrome, a rare autosomal recessive disorder whose definitive diagnosis is often delayed, and to describe the evolution of the sonographic appearance of the kidneys after birth. Methods: Among a large group of fetuses with hyperechoic kidneys, we retrospectively analyzed the prenatal sonographic findings and clinical and postnatal renal sonographic evolution of 11 patients who were found to be affected by Bardet-Biedl syndrome. Results: All 11 fetuses presented enlarged homogeneously hyperechoic kidneys without corticomedullary differentiation. The diagnosis was established before birth in three fetuses thanks to their familial history. It was confirmed during childhood in the remaining eight based on the development of the classic features of the syndrome. In the postnatal period, the prenatal pattern persisted for a few months in all 11 cases. The sonographic aspects of the kidneys normalized in most cases between 1 and 2 years after birth. Conclusions: In affected families, the prenatal appearance of enlarged hyperechoic kidneys without corticomedullary differentiation should prompt a diagnosis of recurrence in the family of Bardet-Biedl syndrome, especially when polydactyly is present. In non-affected families, Bardet-Biedl syndrome should be included in the differential diagnosis whenever such an appearance is discovered in utero. The postnatal evolution of the renal sonographic findings is variable and normalization generally occurs by the age of 2 years. [ABSTRACT FROM AUTHOR]

The article discusses the rare disorder called the Pai syndrome. The disorder is characterized by the association of a midline pericallosal lipoma, median cleft and cutaneous polys of the face. It cites a case of a pregnant woman who was evaluated during gestation because of what were detected during the ultrasound examination.

The article presents a case study of a 27-year-old woman who was referred at 23 weeks' gestation for deformation of the spine. Using ultrasound and computed tomography, the patient was diagnosed of isolated partial agenesis of a vertebral body or asoma. Prenatal diagnosis of asoma facilitates optimization of postnatal management and reduces neonate's risk of developing paralysis. It also allows informed discussion to decide the most appropriate mode of delivery.

A letter to the editor is presented citing the authors' prenatal cerebral ultrasound and magnetic resonance imaging (MRI) findings from a de novo case of glutaric aciduria Type 1.

This article presents the case study of a 27-year old woman at 28 weeks' gestation with the diagnosis of a round mass in the fetal posterior fossa. Tests found were highly suggestive of heterotropic or ectopic brain tissue. Surgical resection was not performed due to the atypicality of the case. The pathogenesis of this rare developmental disease is offered.

Congenital genu recurvatum (CGR) is an extremely rare condition observed at birth. It is associated with, among other malformations, genetic entities such as the Larsen syndrome. When CGR is isolated, orthopedic treatment will usually lead to a good functional prognosis. We report the first case of isolated CGR diagnosed prenatally and suspected to be a consequence of reduced amniotic fluid volume due to leakage following amniocentesis. The etiology and management options for CGR are briefly discussed. [ABSTRACT FROM AUTHOR]

To describe cerebral imaging features of a new syndromic entity related to KIAA1109 loss-of-function variants. All 6 cases demonstrated complex severe cerebral malformations including major cerebral parenchymal thinning with lissencephalic cortical pattern, voluminous germinal matrix, severe ventriculomegaly, corpus callosum agenesis, as well as cerebellar hypoplasia with a characteristic brainstem dysgenesis. Severe cerebral malformations including lissencephalic cortical pattern, severe parenchymal thinning, voluminous germinal matrix, severe ventriculomegaly and cerebellar and brainstem dysgenesis, associated to clubfoot or/and arthrogryposis and visceral anomalies should lead to look for KIAA1109 gene mutation. [Extracted from the article]

The article discusses ways for imroving the detection of midline cerebral abnormalities. It indicates that the absent of cavum septi pellucidi (CSP) . It suggests integrating investigation of the anterior complex, which is demonstrated on both the routine supratentorial axial and coronal planes, as part of routine cerebral sonographic analysis in order to improve the detection of midline anomalies.

Several photographs showing the results of a prenatal diagnosis using ultrasound and magnetic resonance imaging (MRI) of cerebellar cortical dysplasia associated with abnormalities of foliation during the third trimester, are presented.

An abstract of the "Allometric relationship between the transverse cerebellar diameter and the head circumference: impact on prenatal counselling," by M. Massoud and colleagues is presented.

A letter to the editor is presented which demonstrates the case of 24-year-old primigravida who was diagnosed with complete cerebellar agenesis.

An abstract of the article "Prenatal diagnosis of closed spinal dysraphism," by G. Malinger, L. Guibaud, and F. Viñals is presented.

An abstract of the article "The International Fetal Neurology Network (IFN): a 3-year summary of an online academic videoconferencing collaboration," by D. Prayer and colleagues is presented.

An abstract of the conference paper "Isolated' Dandy-Walker malformation on prenatal imaging: Look for subtelomeric deletion and post-natal hydrocephalus" by L. Guibaud and colleagues is presented.

An abstract of the conference paper "Distortion of the anterior part of the interhemispheric fissure. Significance and impact on prenatal diagnosis" by L. Guibaud and colleagues is presented.