Feasibility and Added Value of Fetal DTI Tractography in the Evaluation of an Isolated Short Corpus Callosum: Preliminary Results.

BACKGROUND AND PURPOSE: Prognosis of isolated short corpus callosum is challenging. Our aim was to assess whether fetal DTI tractography can distinguish callosal dysplasia from variants of normal callosal development in fetuses with an isolated short corpus callosum. MATERIALS AND METHODS: This was a retrospective study of 37 cases referred for fetal DTI at 30.4 weeks (range, 25-34 weeks) because of an isolated short corpus callosum less than the 5th percentile by sonography at 26 weeks (range, 22-31 weeks). Tractography quality, the presence of Probst bundles, dysmorphic frontal horns, callosal length (internal cranial occipitofrontal dimension/length of the corpus callosum ratio), and callosal thickness were assessed. Cytogenetic data and neurodevelopmental follow-up were systematically reviewed. RESULTS: Thirty-three of 37 fetal DTIs distinguished the 2 groups: those with Probst bundles (Probst bundles+) in 13/33 cases (40%) and without Probst bundles (Probst bundles-) in 20/33 cases (60%). Internal cranial occipitofrontal dimension/length of the corpus callosum was significantly higher in Probst bundles+ than in Probst bundles-, with a threshold value determined at 3.75 for a sensitivity of 92% (95% CI, 77%-100%) and specificity of 85% (95% CI, 63%-100%). Callosal lipomas (4/4) were all in the Probst bundles- group. More genetic anomalies were found in the Probst bundles+ than in Probst bundles- group (23% versus 10%, P = .08). CONCLUSIONS: Fetal DTI, combined with anatomic, cytogenetic, and clinical characteristics could suggest the possibility of classifying an isolated short corpus callosum as callosal dysplasia and a variant of normal callosal development.

Prevalence of COL4A1 and COL4A2 mutations in severe fetal multifocal hemorrhagic and/or ischemic cerebral lesions.

OBJECTIVE: To establish the prevalence of COL4A1 and COL4A2 gene mutations in fetuses presenting with a phenotype suggestive of cerebral injury. METHODS: This was a single-center retrospective analysis of all cases of fetal cerebral anomalies suggestive of COL4A1 or COL4A2 gene mutation over the period 2009-2018. Inclusion criteria were: (1) severe and/or multifocal hemorrhagic cerebral lesions; (2) multifocal ischemic-hemorrhagic cerebral lesions. These anomalies could be of different ages and associated with schizencephaly or porencephaly. Between fetuses with and those without a mutation, we compared gestational age at the time of diagnosis, parity and fetal gender. RESULTS: Among the 956 cases of cerebral anomaly diagnosed in our center during the 10-year study period, 18 fetuses were identified for inclusion. A pathogenic COL4A1 gene mutation was found in five of these cases, among which four were de-novo mutations. A variant of unknown significance was found in four fetuses: in the COL4A1 gene in one case and in the COL4A2 gene in three cases. No COL4A1 or COL4A2 mutation was found in the remaining nine fetuses. The median (interquartile range) gestational age at diagnosis was significantly lower in cases with a mutation (24 (22-26) weeks) than in cases without a mutation (32 (29.5-34.5) weeks) (P = 0.03). CONCLUSIONS: A phenotype suggestive of cerebral injury was found in 18 of the 956 (1.9%) cases in our population, in 28% of which there was an associated COL4A1 or COL4A2 mutation. COL4A1 and COL4A2 gene mutations should be sought systematically in cases of severe and/or multifocal hemorrhagic or ischemic-hemorrhagic cerebral lesions, with or without schizencephaly or porencephaly. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

[Preliminary results from the French study on prenatal repair for fetal myelomeningoceles (the PRIUM study)]. / Résultats préliminaires de l'étude PRIUM : programme de réparation in utero des myéloméningocèles.

OBJECTIVES: To present the preliminary results of the PRIUM study, a French pilot study of prenatal repair for myelomeningoceles (MMC). MATERIAL AND METHODS: The fetal surgery for MMC is offered in cases of patients that did not opt for termination of pregnancy. RESULTS: Thirty-six patients were referred in an 18-month period. Eight patients were not eligible for prenatal repair. Another type of dysraphism was made in 6 cases (one spina-lipoma, 5 cases of limited dorsal myeloschisis). Twenty-two patients were eligible to fetal surgery. A prenatal repair was performed in three cases (14%). Four patients opted for a conventional postnatal treatment. Fifteen patients opted for termination of the pregnancy. CONCLUSION: The establishment of a prenatal repair of MMC protocol in France was justified. The experience of the first 18months of this study however suggests that only a limited number of couples will choose this procedure after specialized counseling in a reference center.

Prenatal features of isolated subependymal pseudocysts associated with adverse pregnancy outcome.

OBJECTIVES: To identify at prenatal ultrasound (US) the features of apparently isolated subependymal pseudocysts (SEPC) that may indicate underlying pathology and should lead to further investigations. METHODS: This was a retrospective study of cases with SEPC detected on prenatal US and/or magnetic resonance imaging (MRI). Those with apparently isolated SEPC at US were classified into two groups as follows: Group 1 (n = 29): normal prenatal US and MRI (except for SEPC) and normal outcome; Group 2 (n = 12): normal prenatal cerebral US (except for SEPC) and abnormal prenatal cerebral MRI with or without abnormal outcome. A third group (n = 9) included cases with abnormal prenatal US and MRI. The latter cases with obvious cerebral abnormalities at US were excluded from the statistical analysis as they do not represent a diagnostic dilemma for clinicians. Groups 1 and 2 were analyzed, comparing them with respect to their SEPC characteristics (size, number, location in relation to the caudothalamic notch and the ventricular horns and morphology) and extracerebral abnormalities. RESULTS: The mean ± SD SEPC great axis was longer in Group 2 (11.67 ± 5.82 mm) than it was in Group 1 (8.00 ± 5.64 mm) (P = 0.021), suggesting an optimal cut-off for size of SEPC of ≥ 9 mm (sensitivity = 75%, specificity = 62%) to maximize sensitivity for predicting pathological outcome. SEPC adjacent to the temporal horns and SEPC located posterior to the caudothalamic notch were observed more frequently in Group 2, indicating their association with poor outcome (P = 0.003 and P = 0.003, respectively). Atypical morphology and extracerebral abnormalities were observed more frequently in Group 2 (P = 0.013 and P = 0.044, respectively). There was no statistically significant difference between groups for either number or location of cysts along the inferior wall or adjacent to the lateral wall of the frontal horns (P = 0.591 and P = 0.156, respectively). CONCLUSION: When apparently isolated SEPC are observed at prenatal US, further investigations should be performed under the following circumstances: (1) SEPC great axis ≥ 9 mm; (2) SEPC adjacent to the occipital and temporal horns; (3) SEPC located posterior to the caudothalamic notch; (4) SEPC with atypical morphology.

Prenatal unilateral cerebellar hypoplasia in a series of 26 cases: significance and implications for prenatal diagnosis.

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.

Prenatal abnormal features of the fourth ventricle in Joubert syndrome and related disorders.

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.

Periventricular nodular heterotopia on prenatal ultrasound and magnetic resonance imaging.

OBJECTIVES: To describe the prenatal ultrasound and magnetic resonance imaging (MRI) findings suggestive of periventricular nodular heterotopia (PNH). METHODS: This retrospective case series included fetuses referred to our institution for brain MRI between 2007 and 2012, which were diagnosed with PNH and confirmed by postnatal MRI or autopsy. The type of PNH, associated ventriculomegaly and associated malformations are reported. RESULTS: We included 11 fetuses (nine female, two male) with a mean gestational age at diagnosis of 31 (range, 23-34) weeks. PNH lesions were small and diffuse (n = 7), large and multiple (n = 1) or single (n = 3). A targeted ultrasound examination performed before fetal MRI missed the diagnosis in four cases (one diffuse and three single); a further ultrasound examination performed after MRI diagnosed PNH in two of these four cases. Ventriculomegaly was present in six cases (four unilateral and two bilateral). PNH appeared in all cases as nodules of intermediate echogenicity protruding into the ventricular lumen. In all cases of diffuse PNH, the frontal horns and bodies of the lateral ventricles appeared square in shape on coronal view, with irregular borders on axial view. Associated cerebral malformations were observed in seven cases and included corpus callosal agenesis (n = 4, with additional malformations in two) and retrocerebellar cyst (n = 3). Extracerebral malformations were also present in two cases. Maternal MRI was performed in five of the six cases of isolated small and diffuse PNH in female fetuses, and demonstrated PNH in two of these. CONCLUSION: PNH is underdiagnosed at prenatal ultrasound, even on targeted scans. Irregular ventricular borders on axial view and irregular square-shaped lateral ventricles on coronal view are suggestive of PNH at prenatal ultrasound.

Pediatric outcome of children with the prenatal diagnosis of isolated septal agenesis.

BACKGROUND: Isolated Septal Agenesis (SA) is a rare disease with clinical outcomes (especially neurological outcomes) that are unknown. The purpose of this study was to evaluate the clinical outcome of these children. METHODS: We conducted a retrospective multicenter study of 17 children with an isolated SA or SA combined with a moderate ventricular dilatation (VD) that was diagnosed antenatally and confirmed by a magnetic resonance imaging (MRI) performed in the antenatal period. RESULTS: Of the 17 children, 14 had normal neurological examinations, 2 had language development delay and visuo-spatial dyspraxia, and 3 of the 17 children had behavioral problems. Eight children had neuropsychological evaluations, and the results were normal in six cases. There were 3 cases of septo-optic dysplasia (SOD) diagnosed postnatally, which highlighted the difficulties in assessing the optic tract and hypothalamic-pituitary region in antenatal imaging. Language delay and behavioral disorders were the main abnormalities at follow-up. CONCLUSION: The discovery of an isolated SA reveals the difficulties of prenatal diagnosis to correlate the neurological and functional prognosis to morphological findings. The prognosis seemed to be good. It appears necessary to improve the diagnostic performance of fetal brain imaging and to follow-up these children prospectively to assess their long-term cognitive-behavioral outcomes.

Prenatal diagnosis of 18q-syndrome: a case of fetal mosaicism with a normal karyotype in chorionic villi.

We report a case of fetoplacental discrepancy with normal karyotype on chorionic villi and deletion of the long arm of chromosome 18 on amniotic fluid. Cytogenetic tests were repeated because of a short corpus callosum on ultrasound examination. This 18q-syndrome has been reported to be associated with poor neurodevelopmental outcome.

Prenatal and postnatal follow-up of a fetal interhemispheric arachnoid cyst with partial corpus callosum agenesis, asymmetric ventriculomegaly and localized polymicrogyria. Case report.

We report a case of a fetal interhemispheric arachnoid cyst associated with partial callosal agenesis and asymmetric ventriculomegaly. After second trimester ultrasound diagnosis and evaluation, magnetic resonance imaging (MRI) at 28 weeks showed polymicrogyria laterally to the cyst. The parents decided to continue the pregnancy. The diagnosis was confirmed after birth by transfontanellar ultrasound examination and MRI. In the neonatal period, the child was sleepy and showed axial hypotonia. At 1 month of age, he had a normal neurological examination. Cyst-peritoneal shunting was performed at 5 weeks of age because the cyst increased markedly in size, and shunt revision was required at 8 months of age. At 17 months, he had mild left-side hemiparesis but he could walk alone and had begun to speak. To date, the child never experienced seizures. We review other published cases and discuss the postnatal outcome of this rare association.

A second locus for Aicardi-Goutieres syndrome at chromosome 13q14-21.

BACKGROUND: Aicardi-Goutières syndrome (AGS) is an autosomal recessive, early onset encephalopathy characterised by calcification of the basal ganglia, chronic cerebrospinal fluid lymphocytosis, and negative serological investigations for common prenatal infections. AGS may result from a perturbation of interferon alpha metabolism. The disorder is genetically heterogeneous with approximately 50% of families mapping to the first known locus at 3p21 (AGS1). METHODS: A genome-wide scan was performed in 10 families with a clinical diagnosis of AGS in whom linkage to AGS1 had been excluded. Higher density genotyping in regions of interest was also undertaken using the 10 mapping pedigrees and seven additional AGS families. RESULTS: Our results demonstrate significant linkage to a second AGS locus (AGS2) at chromosome 13q14-21 with a maximum multipoint heterogeneity logarithm of the odds (LOD) score of 5.75 at D13S768. The AGS2 locus lies within a 4.7 cM region as defined by a 1 LOD-unit support interval. CONCLUSIONS: We have identified a second AGS disease locus and at least one further locus. As in a number of other conditions, genetic heterogeneity represents a significant obstacle to gene identification in AGS. The localisation of AGS2 represents an important step in this process.

[Brain MRI: ante and postnatal correlations]. / IRM cérébrale: corrélations pré et post-natales.

Fetal brain MRI provides complementary information to ultrasonography exploration, the gold standard for antenatal evaluation. Certain specific correlations between the antenatal and postnatal findings merit discussion: cysts after increase in volume during the perinatal period; certain anomalies are at the limit of resolution (tuber of tuberous sclerosis, heterotopy); anatomic visibility of certain structures does not exclude function deficiency (optical chiasma in septo-optic dysplasia; ventricular dilatation is a frequent sign but can occur in very different entities.

Infantile spasms with basal ganglia MRI hypersignal may reveal mitochondrial disorder due to T8993G MT DNA mutation.

PURPOSE: To report three cases of infantile spasms (IS) with an abnormal magnetic resonance imaging signal in the basal ganglia (Leigh-like syndrome), due to T8993G mt DNA mutation. PATIENTS AND RESULTS: The first sign was, at the end of the first year of life, IS in one case and the combination of IS with behavior changes in the two other cases. Video EEG polygraphy demonstrated both spasms and hypsarrhythmia, but no other kind of seizures. Vigabatrin or steroids controlled the spasms with a follow-up of several years. All 3 patients had hyperlactatorrhachia (3.47 to 7 mmol/l). Axial hypotonia and dystonia appeared by the end of the first year of life. As in cases with the NARP mutation and onset later in life, neuropathy and retinopathy could also be demonstrated. DISCUSSION: Although it is well established that symptomatic IS with hypsarrhythmia mainly result from cortical lesions, this epileptic encephalopathy may also be generated by lesions in the basal ganglia without evidence of cortical damage. This finding suggests that West syndrome is likely to be caused by age-related dysfunction at any level of a cortico-putaminal loop of hyperexcitability.

[The Perruce decree, an opportunity to question the acceptance of a handicap and the relationship between physicians, justice and society]. / L'arrêt Perruche, une occasion de nous interroger sur l'acceptation du handicap et sur les rapports entre médecine, justice et société.

The 'Perruche' decree (confirmed by the Paris Court of Cassation in November 2001) recognizes the right of those born with a handicap to claim for compensation. However, there is a fear that this decree might lead to deviations in the requests submitted for systematic compensation, simply because of a handicap or prejudice, even in the absence of a medical error. The interest of the 'Perruche' decree is that it once again raises the question of the management of handicapped people in our society and the lack of sufficient help from the State. The decree also emphasizes the strong subjacent risk that a handicap could be considered as a failure or a medical error. The excessive ideology of a 'perfect' child may therefore provoke the reject of the idea that a human being may be born with a deficiency or "imperfection". It also reminds us that medical practice remains exposed to errors and incertitude and that a zero risk does not exist, contrary to certain fantastical beliefs fostered by the principle of precaution. The hazard may correspond to the notion of incertitude. But it must not be confused with an error and it implies that which is unforeseeable. It is important that physicians stall the faith in the power of ultramodern techniques. Conversely, they should not claim a right to systematic error, when errors in fact hide authentic faults. The medical discourse must therefore remain responsible.

[Prenatal diagnosis of isolated posterior fossa anomalies: attempt at a simplified approach]. / Diagnostic anténatal des anomalies isolées de la fosse postérieure: tentative d'approche simplifiée.

The authors suggest, after some embryological, anatomical and nosological reviews, a simplified approach mainly based on the appearance of the pons, cerebellar hemispheres and vermis, independently from an associated cystic dilatation of the posterior fossa. Pontocerebellar hypoplasias and partial or total vermian agenesis are detailed because they can be diagnosed with a prenatal MRI. This classification based on our experience and on the literature data should be of value to evaluate the neurological prognosis.