Posterior Fossa Anomalies Research Articles

Accuracy of diagnosis and counseling of fetal brain anomalies prior to 24 weeks of gestational age

Objective: To evaluate the accuracy of prenatal neurosonography in diagnosing underlying causes of fetal ventriculomegaly, posterior fossa anomalies and microcephaly before 24 weeks’ gestational age (GA) and to study the accuracy of prenatal counseling on postnatal prognosis.Methods: A retrospective cohort study based on 146 cases of these fetal brain anomalies before 24 weeks’ GA. Counseling on prognosis was compared with postnatal outcome. Data on genetic testing was analyzed.Results: Out of 146 cases, 135 (92%) were diagnosed correctly before 24 weeks’ GA. Accuracy was 98% (97/99) in cases with multiple anomalies and 81% (38/47) in cases with an isolated abnormality. Counseling on prognosis was correct in 143 out of 146 cases (98%). Prenatal genetic diagnostics detected an anomaly in 51/113 (45%) of cases. In 14/62 (23%) cases prenatal karyotyping was normal, but postnatal array-CGH detected a pathogenic anomaly.Conclusions: Despite the challenges of early gestation, accuracy in diagnosing and counseling fetal brain anomalies before 24 weeks’ GA was high. Prenatal genetic testing is a valuable diagnostic tool and should be offered to all women with fetal brain anomalies. Considering the many different types of anomalies and diverse etiologies, a multidisciplinary approach is essential for counseling on postnatal outcome.

Use of propranolol in a remote region of rural Guatemala to treat a large facial infantile haemangioma

We present a female infant with a right-sided facial and neck haemangioma, from a remote, resource-poor community in rural Guatemala. She received first-line treatment, propranolol, with marked reduction in tumour...

Value of brain MRI when sonography raises suspicion of agenesis of the corpus callosum in fetuses

ObjectiveTo evaluate the role of magnetic resonance imaging (MRI) in fetuses with a previous sonographic suspicion of agenesis of the corpus callosum (ACC) to confirm the diagnosis and to detect associated intracranial anomalies. Material and methodsSingle-center retrospective and descriptive observational study of the brain MRI performed in 78 fetuses with ACC sonographic suspicion between January 2006 and December 2015. Two experts in fetal imaging reviewed the MRI findings to evaluate the presence and morphology of the corpus callosum. When ACC was detected the whole fetal brain anatomy was thoroughly studied to determine the presence of associated anomalies. Prenatal MR imaging findings were compared to postnatal brain MRI or necropsy findings when available. ResultsFetal MRI diagnosed 45 cases of ACC, 12 were partial (26.7%) and 33 complete (73.3%). In 28 cases (62.2%) associated intracranial anomalies were identified. The most often abnormality was ventriculomegaly (78.6%), followed by cortical malformations (53.6%), posterior fossa (25%) and midline anomalies (10.7%). ConclusionFetal brain MRI has an important role in the diagnosis of ACC and detection of associated anomalies. To perform a fetal brain MRI is important in fetuses with sonographic suspicion of ACC.

Valor de la resonancia magnética cerebral en fetos con sospecha ecográfica de agenesia del cuerpo calloso

ObjectiveTo evaluate the role of magnetic resonance imaging (MRI) in fetuses with a previous sonographic suspicion of agenesis of the corpus callosum (ACC) to confirm the diagnosis and to detect associated intracranial anomalies. Material and methodsSingle-center retrospective and descriptive observational study of the brain MRI performed in 78 fetuses with ACC sonographic suspicion between January 2006 and December 2015. Two experts in fetal imaging reviewed the MRI findings to evaluate the presence and morphology of the corpus callosum. When ACC was detected the whole fetal brain anatomy was thoroughly studied to determine the presence of associated anomalies. Prenatal MR imaging findings were compared to postnatal brain MRI or necropsy findings when available. ResultsFetal MRI diagnosed 45 cases of ACC, 12 were partial (26.7%) and 33 complete (73.3%). In 28 cases (62,2%) associated intracranial anomalies were identified. The most often abnormality was ventriculomegaly (78,6%), followed by cortical malformations (53,6%), posterior fossa (25%) and midline anomalies (10,7%). ConclusionFetal brain MRI has an important role in the diagnosis of ACC and detection of associated anomalies. To perform a fetal brain MRI is important in fetuses with sonographic suspicion of ACC.

Combined ultrasound and exome sequencing approach recognizes Opitz G/BBB syndrome in two malformed fetuses.

Orofacial clefts are the most common congenital craniofacial anomalies and can occur as an isolated defect or be associated with other anomalies such as posterior fossa anomalies as a part of several genetic syndromes. We report two consecutive voluntary pregnancy interruptions in a nonconsanguineous couple following the fetal ultrasound finding of cleft lip and palate and posterior fossa anomalies confirmed by means of post-termination examination on the second fetus. The quantitative fluorescent PCR, the karyotype, and the comparative genomic hybridization-array analysis after amniocentesis were normal. Exome sequencing on abortive material from both fetuses detected a missense mutation in MID1, resulting in a clinical diagnosis of Opitz G/BBB syndrome. The same mutation was found in the mother and in her brother, who both revealed cerebellar anomalies at an MRI examination. Our study supports the efficacy of exome sequencing in the presence of both a family history suggestive of an inherited disorder and well-documented ultrasound findings. It reveals the importance of a synergistic effort between gynecologists and geneticists aimed at the integration of the most sophisticated ultrasound techniques with the next-generation sequencing tools to provide a definite diagnosis essential to orient the final decision and to estimate a proper recurrence risk.

A rare face of “PHACE” syndrome with Dandy-Walker malformation, microphthalmia with leukocoria, hearing loss and involuting segmental facial hemangioma

The acronym “PHACE” refers to the syndromic association of posterior fossa anomalies, hemangioma, arterial lesions, cardiac abnormalities/coarctation of the aorta, and eye anomalies. Till now, less than 400 cases of PHACE syndrome have been reported in the medical literature. Its etiopathogenesis is still unknown, and a great deal of genetic and molecular research is required. Moreover, there is always a high probability of misdiagnosis due to the certain factors such as mildly symptomatic patients, hasty diagnosis of relatively common simulating syndromic entities, and low awareness among medical fraternity about the standard diagnostic criteria for PHACE syndrome. Therefore, we report here a case of PHACE syndrome in a 2-year-old female child presenting with Dandy-Walker malformation, microphthalmia, leukocoria, hearing loss, and regressing lesions of large facial infantile hemangioma.

Fetal Cerebellar Vermis Circumference Measured by 2-Dimensional Ultrasound Scan: Reference Range, Feasibility and Reproducibility.

Purpose: To provide 2-dimensional ultrasonographic (2D-US) normograms of cerebellar vermis biometry, as well as to evaluate the feasibility and the reproducibility of these measurements in clinical practice. Materials and Methods: A prospective cross-sectional study of 328 normal singleton pregnancies between 18 and 33 weeks of gestation. Measurements of the fetal cerebellar vermis circumference (VC) in the mid-sagittal plane were performed by both a senior and a junior operator using 2D-US. VC as a function of gestational age (GA) was expressed by regression equations. In 24 fetuses 3-dimensional (3D) reconstructed planes were obtained in order to allow comparisons with 2D-US measurements. The agreement between 2D and 3D measurements and the interobserver variability were assessed by interclass correlation coefficients (ICC). Results: Satisfactory vermis measurements could be obtained in 89.9% of cases. The VC (constant= - 12.21; slope=2.447; r=0.887, p<0.0001) correlated linearly with GA. A high degree of consistency was observed between 2D and 3D ultrasound measurements (ICC=0.846 95% CI 679-0.930) as well as between measurements obtained by different examiners (ICC=0.890 95% CI 989-0.945). Conclusion: 2-dimensional ultrasonographic measurements of cerebellar vermis throughout gestation in the mid-sagittal view seem to be feasible and reproducible enough to be potentially used in clinical practice. Such measurements may supply a tool for accurate identification of posterior fossa anomalies, providing the basis for proper counseling and management and of these conditions.

Differentiating Closed Versus Open Spinal Dysraphisms on Fetal MRI.

The purpose of this study is to identify differences in findings between open and closed spinal dysraphisms seen on fetal MR images. A single-institution retrospective analysis of fetal MR images for spinal dysraphism was performed. Postnatal images and clinical and operative reports were reviewed. Sixteen fetuses with postnatally confirmed closed spinal dysraphisms were included. Of these, 25% (4/16) had posterior fossa anomalies, 12.5% (2/16) had ventriculomegaly, and 37.5% (6/16) had OEIS (omphalocele, exstrophy, imperforate anus, and spinal defects) complex. Of 90 fetuses with postnatally confirmed open spinal dysraphism, 95.6% (86/90) had posterior fossa anomalies, 85.6% (77/90) had ventriculomegaly, and none had OEIS complex. Twenty fetuses with open spinal dysraphism were randomly selected to compare with fetuses with closed spinal dysraphisms. Continuity of the epidermal and subcutaneous tissues with the sac wall on fetal MR images was seen in 93.8% (15/16) of patients with closed spinal dysraphisms, as opposed to 5% (1/20) of patients with open spinal dysraphisms. The mean (± SD) sac wall thickness was less in open (0.7 ± 0.6 mm) than closed (2.9 ± 1.3 mm; p < 0.001) spinal dysraphism. None of the fetuses had T1-hyperintense fat within the defect. On fetal MR images, closed spinal dysraphisms tend to have a sac wall in continuity with the epidermal and subcutaneous tissues, a thicker sac wall, fewer posterior fossa anomalies, and high association with OEIS complex.

Role of Magnetic Resonance Imaging in the Diagnosis of Fetal Brain Anomalies

ABSTRACT Prenatal Ultrasonagraphy (US) is the mainstay modality to diagnose fetal abnormalities especially in early pregnancy. Fetal Magnetic Resonance Imaging (MRI) is a useful tool to confirm and to characterize a pathology that is suspected on US, especially in the detection of central nervous system pathologies. The use of ultrafast imaging tecniques gives additional importantant informations and optimal imaging quality, despite fetal motion, in clinical practice. Diffusion Weighted Imaging (DWI), Diffusion Tensor Imaging (DTI), MR Spetroscopy and Functional studies have potential applications in the fetal brain imaging. Fetal MRI could recognize, in contradistinction to US, the development of fetal brain, the multilayered appearance of the cerebral parenchyma, the timing of sulci development and the myelination. The most common indications for fetal MRI are ventriculomegaly, midline anomalies, malformations of cerebral cortical development, posterior fossa anomalies, suspected haemorraghic-ischemic lesions, tumors. Fetal MRI is a safe and powerful complement to US for clinical management and prognostication. How to cite this article Resta M, Dicuonzo F, Resta M. Role of Magnetic Resonance Imaging in the Diagnosis of Fetal Brain Anomalies. Donald School J Ultrasound Obstet Gynecol 2017;11(4):328-340.

OP07.10: Systematic algorithm for classification of posterior fossa anomalies by targeted 2D and 3D ultrasound

OP07.10: Systematic algorithm for classification of posterior fossa anomalies by targeted <scp>2D</scp> and <scp>3D</scp> ultrasound

Posterior fossa anomalileri: İlişkili anomaliler ve gebeliklerin sonlanma şekilleri

Posterior fossa anomalileri: İlişkili anomaliler ve gebeliklerin sonlanma şekilleri

Systematic review and meta-analysis of isolated posterior fossa malformations on prenatal imaging (part 2): neurodevelopmental outcome.

Diagnosis of isolated posterior fossa anomalies in children is biased by the fact that only those that are symptomatic are brought to the attention of the appropriate clinical personnel, and the reported rate is often affected by the adoption of different nomenclature, diagnostic criteria, outcome measures, duration of follow-up and neurodevelopmental tools. The aim of this systematic review was to explore the neurodevelopmental outcome of fetuses with a prenatal diagnosis of isolated posterior fossa anomalies. MEDLINE and EMBASE were searched electronically, utilizing combinations of the relevant medical subject heading terms for 'posterior fossa' and 'outcome'. Studies assessing the neurodevelopmental outcome in children with a prenatal diagnosis of isolated posterior fossa malformations were considered eligible. The posterior fossa anomalies analyzed included Dandy-Walker malformation (DWM), mega cisterna magna (MCM), Blake's pouch cyst (BPC) and vermian hypoplasia (VH). Two authors reviewed all abstracts independently. Quality assessment of the included studies was performed using the Newcastle-Ottawa Scale for cohort studies. Meta-analyses of proportions were used to combine data, and between-study heterogeneity was explored using the I(2) statistic. A total of 1640 articles were identified; 95 were assessed for eligibility and a total of 16 studies were included in the systematic review. The overall rate of abnormal neurodevelopmental outcome in children with a prenatal diagnosis of DWM was 58.2% (95% CI, 21.8-90.0%) and varied from 0-100%. In those with a prenatal diagnosis of MCM, the rate of abnormal neurodevelopmental outcome was 13.8% (95% CI, 7.3-21.9%), with a range of 0-50%. There was no significant association between BPC and the occurrence of abnormal neurodevelopmental delay, with a rate of 4.7% (95% CI, 0.7-12.1%) and range of 0-5%. Although affected by the very small number of studies, there was a non-significant occurrence of abnormal neurodevelopmental delay in children with a prenatal diagnosis of VH, with a rate of 30.7% (95% CI, 0.6-79.1%) and range of 0-100%. Fetuses diagnosed with isolated DWM are at high risk of abnormal neurodevelopmental outcome, while isolated MCM or BPC have a generally favorable outcome. The risk of abnormal developmental delay in cases with isolated VH needs to be further assessed. In view of the wide heterogeneity in study design, time of follow-up, neurodevelopmental tests used and the very small number of included cases, further future large prospective studies with standardized and objective protocols for diagnosis and follow-up are needed in order to ascertain the rate of abnormal neurodevelopmental outcome in children with isolated posterior fossa anomalies. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Systematic review and meta-analysis of isolated posterior fossa malformations on prenatal ultrasound imaging (part 1): nomenclature, diagnostic accuracy and associated anomalies.

To explore the outcome in fetuses with prenatal diagnosis of posterior fossa anomalies apparently isolated on ultrasound imaging. MEDLINE and EMBASE were searched electronically utilizing combinations of relevant medical subject headings for 'posterior fossa' and 'outcome'. The posterior fossa anomalies analyzed were Dandy-Walker malformation (DWM), mega cisterna magna (MCM), Blake's pouch cyst (BPC) and vermian hypoplasia (VH). The outcomes observed were rate of chromosomal abnormalities, additional anomalies detected at prenatal magnetic resonance imaging (MRI), additional anomalies detected at postnatal imaging and concordance between prenatal and postnatal diagnoses. Only isolated cases of posterior fossa anomalies - defined as having no cerebral or extracerebral additional anomalies detected on ultrasound examination - were included in the analysis. Quality assessment of the included studies was performed using the Newcastle-Ottawa Scale for cohort studies. We used meta-analyses of proportions to combine data and fixed- or random-effects models according to the heterogeneity of the results. Twenty-two studies including 531 fetuses with posterior fossa anomalies were included in this systematic review. The prevalence of chromosomal abnormalities in fetuses with isolated DWM was 16.3% (95% CI, 8.7-25.7%). The prevalence of additional central nervous system (CNS) abnormalities that were missed at ultrasound examination and detected only at prenatal MRI was 13.7% (95% CI, 0.2-42.6%), and the prevalence of additional CNS anomalies that were missed at prenatal imaging and detected only after birth was 18.2% (95% CI, 6.2-34.6%). Prenatal diagnosis was not confirmed after birth in 28.2% (95% CI, 8.5-53.9%) of cases. MCM was not significantly associated with additional anomalies detected at prenatal MRI or detected after birth. Prenatal diagnosis was not confirmed postnatally in 7.1% (95% CI, 2.3-14.5%) of cases. The rate of chromosomal anomalies in fetuses with isolated BPC was 5.2% (95% CI, 0.9-12.7%) and there was no associated CNS anomaly detected at prenatal MRI or only after birth. Prenatal diagnosis of BPC was not confirmed after birth in 9.8% (95% CI, 2.9-20.1%) of cases. The rate of chromosomal anomalies in fetuses with isolated VH was 6.5% (95% CI, 0.8-17.1%) and there were no additional anomalies detected at prenatal MRI (0% (95% CI, 0.0-45.9%)). The proportions of cerebral anomalies detected only after birth was 14.2% (95% CI, 2.9-31.9%). Prenatal diagnosis was not confirmed after birth in 32.4% (95% CI, 18.3-48.4%) of cases. DWM apparently isolated on ultrasound imaging is a condition with a high risk for chromosomal and associated structural anomalies. Isolated MCM and BPC have a low risk for aneuploidy or associated structural anomalies. The small number of cases with isolated VH prevents robust conclusions regarding their management from being drawn. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

3D Super-Resolution Motion-Corrected MRI: Validation of Fetal Posterior Fossa Measurements.

Current diagnosis of fetal posterior fossa anomalies by sonography and conventional MRI is limited by fetal position, motion, and by two-dimensional (2D), rather than three-dimensional (3D), representation.In this study, we aimed to validate the use of a novel magnetic resonance imaging (MRI) technique, 3D super-resolution motion-corrected MRI, to image the fetal posterior fossa. From a database of pregnant women who received fetal MRIs at our institution, images of49 normal fetal brains were reconstructed.Six measurements of the cerebellum, vermis, and pons were obtained for all cases on 2D conventional and 3D reconstructed MRI, and the agreement between the two methods was determined using concordance correlation coefficients. Concordance of axial and coronalmeasurements of the transcerebellar diameter was also assessed within each method. Between the two methods, the concordance of measurements was high for all six structures (P < .001), and was highest for larger structures such as the transcerebellar diameter. Within each method, agreement of axial and coronal measurements of the transcerebellar diameter was superior in 3D reconstructed MRI compared to 2D conventional MRI (P < .001). This comparison study validates the use of 3D super-resolution motion-corrected MRI for imaging the fetal posterior fossa, as this technique results in linear measurements that have high concordance with 2D conventional MRI measurements. Lengths of the transcerebellar diameter measured within a 3D reconstruction are more concordant between imaging planes, as they correct for fetal motion and orthogonal slice acquisition. This technique will facilitate further study of fetal abnormalities of the posterior fossa.

Diagnostic Value of Prenatal MR Imaging in the Detection of Brain Malformations in Fetuses before the 26th Week of Gestational Age.

In several countries, laws and regulations allow abortion for medical reasons within 24-25 weeks of gestational age. We investigated the diagnostic value of prenatal MR imaging for brain malformations within 25 weeks of gestational age. We retrospectively included fetuses within 25 weeks of gestational age who had undergone both prenatal and postnatal MR imaging of the brain between 2002 and 2014. Two senior pediatric neuroradiologists evaluated prenatal MR imaging examinations blinded to postnatal MR imaging findings. With postnatal MR imaging used as the reference standard, we calculated the sensitivity, specificity, positive predictive value, and negative predictive value of the prenatal MR imaging in detecting brain malformations. One-hundred nine fetuses (median gestational age at prenatal MR imaging: 22 weeks; range, 21-25 weeks) were included in this study. According to the reference standard, 111 malformations were detected. Prenatal MR imaging failed to detect correctly 11 of the 111 malformations: 3 midline malformations, 5 disorders of cortical development, 2 posterior fossa anomalies, and 1 vascular malformation. Prenatal MR imaging misdiagnosed 3 findings as pathologic in the posterior fossa. The diagnostic value of prenatal MR imaging between 21 and 25 weeks' gestational age is very high, with limitations of sensitivity regarding the detection of disorders of cortical development.

Pediatric central nervous system vascular malformations.

Pediatric central nervous system (CNS) vascular anomalies include lesions found only in the pediatric population and also the full gamut of vascular lesions found in adults. Pediatric-specific lesions discussed here include infantile hemangioma, vein of Galen malformation and dural sinus malformation. Some CNS vascular lesions that occur in adults, such as arteriovenous malformation, have somewhat distinct manifestations in children, and those are also discussed. Additionally, children with CNS vascular malformations often have associated broader vascular conditions, e.g., PHACES (posterior fossa anomalies, hemangioma, arterial anomalies, cardiac anomalies, eye anomalies and sternal anomalies), hereditary hemorrhagic telangiectasia, and capillary malformation-arteriovenous malformation syndrome (related to the RASA1 mutation). The treatment of pediatric CNS vascular malformations has greatly benefited from advances in endovascular therapy, including technical advances in adult interventional neuroradiology. Dramatic advances in therapy are expected to stem from increased understanding of the genetics and vascular biology that underlie pediatric CNS vascular malformations.

Congenital basis of posterior fossa anomalies.

The classification of posterior fossa congenital anomalies has been a controversial topic. Advances in genetics and imaging have allowed a better understanding of the embryologic development of these abnormalities. A new classification schema correlates the embryologic, morphologic, and genetic bases of these anomalies in order to better distinguish and describe them. Although they provide a better understanding of the clinical aspects and genetics of these disorders, it is crucial for the radiologist to be able to diagnose the congenital posterior fossa anomalies based on their morphology, since neuroimaging is usually the initial step when these disorders are suspected. We divide the most common posterior fossa congenital anomalies into two groups: 1) hindbrain malformations, including diseases with cerebellar or vermian agenesis, aplasia or hypoplasia and cystic posterior fossa anomalies; and 2) cranial vault malformations. In addition, we will review the embryologic development of the posterior fossa and, from the perspective of embryonic development, will describe the imaging appearance of congenital posterior fossa anomalies. Knowledge of the developmental bases of these malformations facilitates detection of the morphological changes identified on imaging, allowing accurate differentiation and diagnosis of congenital posterior fossa anomalies.

English

INTRODUCTION: A syndrome is defined as a recognizable pattern of medical conditions that occur together. Initially described as an association of large cutaneous hemangiomas of the head and anomalies of the cerebral vasculature by pascual-castroviejo in 1978. Subsequently been coined the term PHACE association by Frieden et.al. Frieden created the term PHACE, which is an acronym which refers to Posterior fossa anomalies, Hemangioma, Arterial lesions, Cardiac abnormalities/ coarctation of the aorta and Eye anomalies. PHACES SYNDROME is PHACE syndrome plus: Sternal cleft, supraumbilical raphe, or both.

Date-independent parameters: an innovative method to assess fetal cerebellar vermis.

The objectives of this paper were to identify gestational age-independent parameters for cerebellar vermis (CV) evaluation and examine their use in CV integrity assessments. Using three-dimensional ultrasonography, we obtained the following measurements from 217 pregnant women carrying 18-37-week-old fetuses: the largest area of the CV, vermal craniocaudal distance (VCC), vermal anterior to posterior diameter, and vermal perimeter (VP). In addition, fetal growth parameters (biparietal diameter, head circumference femoral length [FL], humeral length, transverse cerebellar diameter, and abdominal circumference) were evaluated. The ratios of the CV dimensions to each other and to the fetal growth parameters were calculated. Ratios showing no significant correlation with gestational age and acceptable internal validity in subsequent bootstrap analyses were chosen. The normal ranges of the specific parameters were compared with cases identified with posterior fossa anomalies (PFA). The ratios VP/FL (mean 1.20, SD 0.09), VCC/FL (mean 0.36, SD 0.03), and VCC/VP (mean 0.3, SD 0.03) were chosen using our protocol. These parameters were not significantly different between normal fetuses and those with PFA and an intact vermis. However, VP/FL and VCC/FL values were abnormal in cases of hypoplastic vermis or vermian agenesis, while the VP/VCC value was abnormal only in cases of vermian agenesis. The VP/FL, VCC/FL, and VCC/VP ratios are gestational age-independent parameters in evaluation of CV integrity.

Congenital abnormalities of the posterior fossa.

The frequency and importance of the evaluation of the posterior fossa have increased significantly over the past 20 years owing to advances in neuroimaging. Nowadays, conventional and advanced neuroimaging techniques allow detailed evaluation of the complex anatomic structures within the posterior fossa. A wide spectrum of congenital abnormalities has been demonstrated, including malformations (anomalies due to an alteration of the primary developmental program caused by a genetic defect) and disruptions (anomalies due to the breakdown of a structure that had a normal developmental potential). Familiarity with the spectrum of congenital posterior fossa anomalies and their well-defined diagnostic criteria is crucial for optimal therapy, an accurate prognosis, and correct genetic counseling. The authors discuss the spectrum of posterior fossa malformations and disruptions, with emphasis on neuroimaging findings (including diagnostic criteria), neurologic presentation, systemic involvement, prognosis, and risk of recurrence.