Hydrocephalus associated with a molar tooth sign: A distinct subtype of Joubert syndrome.

Hydrocephalus is rarely described in Joubert-Boltshauser syndrome (JBTS). The aim of this study was to investigate whether this association is a chance occurrence or potentially signifies a new phenotypic subtype. The databases of Wolfson Medical Center, Sourasky Medical Center, and EB's personal collection were reviewed. Records from an additional family were obtained from RG. The patients' medical records, prenatal ultrasounds, and magnetic resonance imaging were assessed. In addition, we reviewed the medical literature for the association of ventriculomegaly/hydrocephalus (VM/HC) in JBTS. Only seven cases (from five families) were found with prenatal onset of VM/HC, diagnosed during the second trimester; three pregnancies were terminated, one was stillborn and three were born, of which one died within a week, and another died at the age of 6 years. Additional central nervous system findings included dysgenesis of the corpus callosum, delayed sulcation, polymicrogyria, and pachygyria. We found 16 publications describing 54 patients with JBTS and VM/HC: only five were diagnosed at birth and three were diagnosed prenatally. Hydrocephalus is extremely rare in JBTS. The recurrence of this association, reported in several publications in multiple family members, suggests that it might represent a new phenotypic subtype of JBTS possibly associated with specific genes or variants. Further genetic studies are needed to confirm this hypothesis. WHAT THIS PAPER ADDS: The association of fetal hydrocephalus with Joubert-Boltshauser syndrome (JBTS) is very rare but not a chance association. This association represents a new phenotypic subtype of JBTS possibly linked to specific genes or variants.

Expanding the natural history of CASK-related disorders to the prenatal period.

AIM: To assess whether microcephaly with pontine and cerebellar hypoplasia (MICPCH) could manifest in the prenatal period in patients with calcium/calmodulin-dependent serine protein kinase (CASK) gene disorders. METHOD: In this international multicentre retrospective study, we contacted a CASK parents' social media group and colleagues with expertise in cerebellar malformations and asked them to supply clinical and imaging information. Centiles and standard deviations (SD) were calculated according to age by nomograms. RESULTS: The study consisted of 49 patients (44 females and 5 males). Information regarding prenatal head circumference was available in 19 patients; 11 out of 19 had a fetal head circumference below -2SD (range -4.1SD to -2.02SD, mean gestational age at diagnosis 20 weeks). Progressive prenatal deceleration of head circumference growth rate was observed in 15 out of 19. At birth, 20 out of 42 had a head circumference below -2SD. A total of 6 out of 15 fetuses had a TCD z-score below -2 (range -5.88 to -2.02). INTERPRETATION: This study expands the natural history of CASK-related disorders to the prenatal period, showing evidence of progressive deceleration of head circumference growth rate, head circumference below -2SD, or small TCD. Most cases will not be diagnosed according to current recommendations for fetal central nervous system routine assessment. Consecutive measurements and genetic studies are advised in the presence of progressive deceleration of head circumference growth rates or small TCD. WHAT THIS PAPER ADDS: Progressive deceleration of fetal head circumference growth rate can be observed. A small transcerebellar diameter is an additional important manifestation. Most cases will not be diagnosed according to current recommendations for fetal central nervous system routine assessment. Consecutive measurements are advised when measurements are within the low range of norm.

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.

Major brain malformations: corpus callosum dysgenesis, agenesis of septum pellucidum and polymicrogyria in patients with BCORL1-related disorders.

OBJECTIVE: BCORL1, a transcriptional co-repressor, has a role in cortical migration, neuronal differentiation, maturation, and cerebellar development. We describe BCORL1 as a new genetic cause for major brain malformations. METHODS AND RESULTS: We report three patients from two unrelated families with neonatal onset intractable epilepsy and profound global developmental delay. Brain MRI of two siblings from the first family depicted hypoplastic corpus callosum and septal agenesis (ASP) in the older brother and unilateral perisylvian polymicrogyria (PMG) in the younger one. MRI of the patient from the second family demonstrated complete agenesis of corpus callosum (CC). Whole Exome Sequencing revealed a novel hemizygous variant in NM_021946.5 (BCORL1):c.796C>T (p.Pro266Ser) in the two siblings from the first family and the NM_021946.5 (BCORL1): c.3376G>A; p.Asp1126Asn variant in the patient from the second family, both variants inherited from healthy mothers. We reviewed the patients' charts and MRIs and compared the phenotype to the other published BCORL1-related cases. Brain malformations have not been previously described in association with the BCORL1 phenotype. We discuss the potential influence of BCORL1 on brain development. CONCLUSIONS: We suggest that BCORL1 variants present with a spectrum of neurodevelopmental disorders and can lead to major brain malformations originating at different stages of fetal development. We suggest adding BCORL1 to the genetic causes of PMG, ASP, and CC dysgenesis.

A New Insight on Exophytic Serous Borderline Adnexal Tumors: Specific Sonographic Features.

OBJECTIVES: To characterize and compare the sonographic features of exophytic serous borderline ovarian tumors (ESBOT) with those of high-grade serous carcinoma of the ovary (HGSC). METHODS: Seven patients with histological diagnosis of ESBOT diagnosed between 2011 and 2019 and 10 consecutive cases of HGSC detected during 2019, both depicting an exophytic growth pattern, were identified retrospectively. The sonographic imaging of the masses was reassessed and characterized according to the International Ovarian Tumor Analysis terms. RESULTS: A unilateral irregular solid adnexal mass was demonstrated in all patients with ESBOT. The mass typically wrapped an apparently normal ovary, with a clear demarcation line depicted between them and it contained tiny cystic inclusions and calcifications. On color Doppler study of all the ESBOT cases, a unique vascular pattern could be demonstrated: an intratumoral vascular bundle originating from the ovarian vessels and supplying a rich radial blood flow to the tumor periphery. These characteristic morphological and color Doppler features could not be observed in any of the HGSC cases (P < .001). In 42.8% of the patients with ESBOT, additional unilocular-solid components (ipsilateral or contralateral) could be detected, whereas all the HGSC patients presented with a multilocular-solid tumor morphology (P < .001). The interface of the external mass border with the adjacent pelvic walls was regular in all the cases with ESBOT, whereas in 80% of HGSC patients, it was irregular, suggesting invasiveness (P = .002). CONCLUSIONS: ESBOT can mimic HGSC. Our results suggest that ESBOT has specific B-mode and color Doppler features, enabling differentiation from HGSC and planning appropriate intervention.

White matter abnormalities and iron deposition in prenatal mucolipidosis IV- fetal imaging and pathology.

Mucolipidosis type IV (MLIV; OMIM 252,650) is an autosomal recessive lysosomal disorder caused by mutations in MCOLN1. MLIV causes psychomotor impairment and progressive vision loss. The major hallmarks of postnatal brain MRI are hypomyelination and thin corpus callosum. Human brain pathology data is scarce and demonstrates storage of various inclusion bodies in all neuronal cell types. The current study describes novel fetal brain MRI and neuropathology findings in a fetus with MLIV. Fetal MRI was performed at 32 and 35 weeks of gestation due to an older sibling with spastic quadriparesis, visual impairment and hypomyelination. Following abnormal fetal MRI results, the parents requested termination of pregnancy according to Israeli regulations. Fetal autopsy was performed after approval of the high committee for pregnancy termination. A genetic diagnosis of MLIV was established in the fetus and sibling. Sequential fetal brain MRI showed progressive curvilinear hypointensities on T2-weighted images in the frontal deep white matter and a thin corpus callosum. Fetal brain pathology exhibited a thin corpus callosum and hypercellular white matter composed of reactive astrocytes and microglia, multifocal white matter abnormalities with mineralized deposits, and numerous aggregates of microglia with focal intracellular iron accumulation most prominent in the frontal lobes. This is the first description in the literature of brain MRI and neuropathology in a fetus with MLIV. The findings demonstrate prenatal white matter involvement with significant activation of microglia and astrocytes and impaired iron metabolism.

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.

Biallelic mutations in EXOC3L2 cause a novel syndrome that affects the brain, kidney and blood.

BACKGROUND: Dandy-Walker malformation features agenesis/hypoplasia of the cerebellar vermis, cystic dilatation of the fourth ventricle and enlargement of posterior fossa. Although Dandy-Walker malformation is relatively common and several genes were linked to the syndrome, the genetic cause in the majority of cases is unknown. OBJECTIVE: To identify the mutated gene responsible for Dandy-Walker malformation, kidney disease and bone marrow failure in four patients from two unrelated families. METHODS: Medical assessment, sonographic, MRI and pathological studies were used to define phenotype. Chromosomal microarray analysis and whole-exome sequence were performed to unravel the genotype. RESULTS: We report four subjects from two unrelated families with homozygous mutations in the Exocyst Complex Component 3-Like-2 gene (EXOC3L2).EXOC3L2 functions in trafficking of post-Golgi vesicles to the plasma membrane. In the first family a missense mutation in a highly conserved amino acid, p.Leu41Gln, was found in three fetuses; all had severe forms of Dandy-Walker malformation that was detectable by prenatal ultrasonography and confirmed by autopsy. In the second family, the affected child carried a nonsense mutation, p.Arg72*, and no detected protein. He had peritrigonal and cerebellar white matter abnormalities with enlargement of the ventricular trigones, developmental delay, pituitary hypoplasia, severe renal dysplasia and bone marrow failure. CONCLUSION: We propose that biallelic EXOC3L2 mutations lead to a novel syndrome that affects hindbrain development, kidney and possibly the bone marrow.

A new method for evaluating short fetal corpus callosum.

OBJECTIVE: Sonographic diagnosis of short corpus callosum (SCC) is based on measurement of a short for gestational age antero-posterior length of the corpus callosum (CC) in the midsagittal plane. We suggest a new method for evaluating SCC without referring to biometry tables. METHODS: We measured the ratio between the CC length and the internal cranial occipitofrontal dimension (ICOFD) in the midsagittal plane in 399 normal fetuses at 20 + 6 to 35 + 3 weeks of gestation and in 31 fetuses with a diagnosis of a SCC and compared the mean ratio between two groups. The impact of cephalic biometric parameters, fetal presentation, and gender was assessed. RESULTS: The ICOFD/CC length for normal pregnancies was constant throughout the pregnancy (2.35 ± 0.11). There was no correlation between the ICOFD/CC length and cephalic index, Biparietal Diameter (BPD), head circumference, fetal sex, or fetal presentation. The ratio of pregnancies with SCC was significantly higher: 3.20 ± 0.84 (P < .0001). CONCLUSION: The ICOFD/CC length practically does not change throughout a normal pregnancy. The ratio was significantly higher in pregnancies with SCC. Measuring this ratio during fetal anatomical scan may enable rapid evaluation of the CC without the need to refer to biometry tables.

Ultrasound Nomograms of the Fetal Optic Nerve Sheath Diameter.

OBJECTIVE: To construct prenatal age-specific reference intervals for sonographic measurements of the optic nerve sheath diameter (ONSD) during gestation in normal fetuses. MATERIALS AND METHODS: Prospective cross-sectional study of fetuses assessed in antenatal ultrasound units between 2010 and 2014. The examination was based on a technique for the sonographic assessment of ONSD previously published by our group. The mean values and SDs of the ONSD were modeled as a function of the gestational week by curve estimation analysis based on the highest adjusted R2 coefficient. Repeatability tests were performed to assess intraobserver variability and interobserver agreement. RESULTS: During the study period 364 healthy fetuses were enrolled. The mean values for the ONSD varied from 0.6 mm at 15-16 weeks to 2.8 mm at 37-38 weeks. The ONSD grows in a linear fashion throughout gestation, with a quadratic equation providing an optimal fit to the data (adjusted R2 = 0.957). CONCLUSION: Sonographic age-specific references for the fetal ONSD are presented. This data may assist in the decision-making process in fetuses with a suspected increase in intracranial pressure, or anomalies affecting the development of optic stalks, such as optic hypoplasia and septo-optic dysplasia.

Early Transient Prenatal Ultrasound Features of Choanal Atresia.

We present a case series of early second-trimester prenatal ultrasound (US) features in 4 fetuses with a confirmed diagnosis of choanal atresia. The clinical characteristics and outcomes evaluated included prenatal US findings, genetic analyses, postmortem autopsies (2 cases), and computed tomographic findings. A transient large nasal cavity was detected by US in all 4 fetuses. This finding disappeared a few weeks later. Three cases were unilateral choanal atresia, and 1 was bilateral. Transient enlargement of the nasal cavity in early pregnancy appears to be a US sign of choanal atresia.

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.

Familial Brain Periventricular Pseudocysts.

INTRODUCTION: We report the rare finding of recurrent periventricular pseudocysts (PVPC) in consecutive pregnancies in 4 families and their postnatal outcome. MATERIALS AND METHODS: We reviewed the databases of 3 large ultrasound units searching for the diagnosis of PVPC in 2 pregnancies of the same patient. RESULTS: The first case of recurrent PVPC was diagnosed in 2011 and since then 3 additional families were diagnosed (8 cases of PVPC all in all). All fetuses underwent fetal MRI that confirmed the presence of frontal or frontocaudal PVPC. Amniocentesis, when performed, demonstrated a normal karyotype. Termination of pregnancy was carried out in 2 pregnancies in 2 of 4 families. The remaining 6 pregnancies ended with a term delivery, and to date all babies are developing normally. CONCLUSION: The rare finding of recurrent brain PVPC in consecutive pregnancies raises the possibility of a hereditary etiology as opposed to a sporadic event. As in isolated PVPC, frontocaudal 'familial PVPC' appears to carry a favorable prognosis.

Malformations of Cortical Development: From Postnatal to Fetal Imaging.

Abnormal fetal corticogenesis results in malformations of cortical development (MCD). Abnormal cell proliferation leads to microcephaly or megalencephaly, incomplete neuronal migration results in heterotopia and lissencephaly, neuronal overmigration manifests as cobblestone malformations, and anomalous postmigrational cortical organization is responsible for polymicrogyria and focal cortical dysplasias. MCD comprises various congenital brain disorders, caused by different genetic, infectious, or vascular etiologies and is associated with significant neurological morbidity. Although MCD are rarely diagnosed prenatally, both dedicated multiplanar neurosonography and magnetic resonance imaging enable good demonstration of fetal cortical development. The imaging signs of fetal MCD are: delayed or absent cerebral sulcation; premature abnormal sulci; thin and irregular hemispheric parenchyma; wide abnormal overdeveloped gyri; wide opening of isolated sulci; nodular bulging into the lateral ventricles; cortical clefts; intraparenchymal echogenic nodules; and cortical thickening. The postnatal and prenatal imaging features of four main malformations of cortical development-lissencephaly, cobblestone malformations, periventricular nodular heterotopia, and polymicrogyria-are described.

Prenatal sonographic features of triploidy at 12-16 weeks.

OBJECTIVE: The purpose of our study was to describe the sonographic appearance of triploidy in early pregnancy. METHODS: We report the sonographic characteristics of a cohort of fetal triploid cases detected at targeted ultrasonographic vaginal examinations between 12 and 16 weeks of gestation from 2008 to 2014. Indications for fetal karyotype following ultrasound were maternal request, advanced maternal age, increased nuchal translucency, and/or fetal abnormalities. RESULTS: Triploidy was detected in 25 cases during the 6 years of the study period with an estimated incidence of ~1 in 5000 pregnancies. Four cases had molar changes in the placenta. Among the remaining 21 cases, a consistent sonographic pattern was noted, which included the combination of asymmetric growth restriction with abdominal circumference lagging 2 weeks behind head circumference in 21/21, oligohydramnios in 20/21, abnormal posterior fossa or enlarged fourth ventricle in 20/21, and absent gall bladder in 17/21. Other findings present in more than 50% of cases included cardiac (70%) and renal (55%) abnormalities, clenched hands (55%), and hypoplastic lungs (67%). CONCLUSION: Fetal triploidy can manifest at 12-16 weeks with molar changes in the placenta or with a cluster of unusual sonographic findings whose presence should prompt appropriate testing for diagnosis in early pregnancy. © 2016 John Wiley & Sons, Ltd.

The 'Brain Shadowing Sign': A Novel Marker of Fetal Craniosynostosis.

INTRODUCTION: The prenatal diagnosis of fetal craniosynostosis is challenging, especially in single-suture cases. When sutures are obliterated, sound waves fail to penetrate the cortical bone, creating an evident acoustic shadow on the underlying brain. The objective of this study was to evaluate the yield of the 'brain shadowing sign' (BSS) as a novel sonographic marker for craniosynostosis. SUBJECTS AND METHODS: Patients with an antenatal diagnosis of fetal craniosynostosis (cases) and healthy controls paired for gestational age were enrolled in this retrospective case-control study. Two-dimensional scans were assessed by three examiners for the presence of the BSS and additional fetal findings. RESULTS: The BSS was clearly depicted in all 24 cases on the first analysis and in 22 cases on the second analysis. No fetus from the control group (n = 48) presented the BSS in any of the analyses. Fifteen cases had isolated craniosynostosis and 9 were syndromic (Apert, Saethre-Chotzen and craniofrontonasal syndromes), which were diagnosed significantly earlier due to additional malformations. DISCUSSION: The BSS is a novel sonographic marker of craniosynostosis which can be used to increase the diagnostic rate of this rare condition and does not require the use of high-definition three-dimensional transducers to be depicted.

Measuring the perimeter and area of the Sylvian fissure in fetal brain during normal pregnancies using 3-dimensional ultrasound.

OBJECTIVES: The purpose of this study was to demonstrate the normal perimeter and area of the three orthogonal planes (axial, sagittal and coronal) of the fetal Sylvian fissure along pregnancy using 3-dimensional (3D) ultrasound. METHODS: Ultrasound volumes of fetal head were acquired prospectively in 55 fetuses between 12 and 33 gestational weeks. All volumes were analyzed offline by two examiners separately. The largest axial, sagittal and coronal planes of the Sylvian fissure were identified, and the area and perimeter were measured. RESULTS: Measurements of the Sylvian fissure were demonstrated in 54 out of 55 volumes (98%). In all three planes, a linear growth was demonstrated along gestation. All measurements significantly correlated to gestational age and head circumference (p < 0.01). The Sylvian fissure was found to grow asymmetrically, more at the anterior-posterior direction than laterally or to the inferior-superior directions. CONCLUSIONS: The Sylvian fissure grows linearly and has a distinct form in each developmental stage. The fissure is identifiable and measurable as early as 12 weeks gestation.

Ovarian Pregnancy Following in Vitro Fertilization in a Woman After Bilateral Salpingectomy: A Case Report and Review of the Literature.

We present a rare case of ovarian pregnancy that occurred in a woman who underwent in vitro fertilization (IVF) after bilateral salpingectomy. The patient presented with abdominal pain and a positive pregnancy test. Ovarian pregnancy was diagnosed owing to a suspicious mass detected on ultrasound. She underwent laparoscopy to confirm the diagnosis, which was subsequently verified by histopathological examination. The question that comes in mind is: How did the pregnancy get there? After a review of the literature, we have found a few possible explanations for the mechanism of this rare event. This case emphasizes the need for vigilance in suspecting ectopic pregnancy even in women who have undergone salpingectomy.

Small size, big problems: insights and difficulties in prenatal diagnosis of fetal microcephaly.

Microcephaly is a sign, not a diagnosis. Its incidence varies widely due to the differences in the definition and the population being studied. It is strongly related to neurodevelopmental disorders. Differences in definitions and measurement techniques between fetuses and newborns pose a great challenge for the diagnosis and prognostication of fetal microcephaly. A false positive diagnosis can result (in countries where it is legal) in erroneous termination of pregnancy, where a false negative diagnosis might lead to the birth of a microcephalic newborn. Microcephaly in growth restricted fetuses deserves special attention and separate evaluation as it is an important prognostic factor, and not necessarily part of the general growth retardation. Several genetic syndromes incorporating microcephaly and intrauterine growth retardation (IUGR) are discussed. Deceleration of the head circumference (HC) growth rate even when the HC is still within normal limits might be the only clue for developing microcephaly and should be considered during fetal head growth follow up. Combining additional parameters such as a positive family history, associated anomalies, and new measurement parameters can improve prediction in about 50% of cases, and thus should be part of the prenatal workup. Advances in imaging modalities and in prenatal genetic investigation along with the emergence of new growth charts can also improve diagnostic accuracy. In this article, we review the different definitions and etiologies of fetal microcephaly, discuss difficulties in diagnosis, investigate the reasons for the low yield of prenatal diagnosis, and provide improvement suggestions. Finally, we suggest an updated algorithm that will aid in the diagnosis and management of fetal microcephaly.

Sonography of the fetal cochlea in the early second trimester of pregnancy.

OBJECTIVES: To examine the feasibility of imaging the fetal cochlea in the early second trimester. METHODS: This study included 42 healthy fetuses of low-risk pregnancies between 14 and 16 weeks. The coronal head sections via sagittal and lateral acoustic windows were used for cochlear visualization. The coronal plane was directed across the thalamus, oriented to the petrous part of the temporal bones. All fetuses were examined by 2-dimensional(2D) transvaginal sonography. Transabdominal scans were added in 11 fetuses at 16 weeks. Three-dimensional (3D) multiplanar reconstruction was used for coronal plane reformatting in cases with inappropriate head positioning for 2D scanning. RESULTS: Because of temporal bone hypomineralization in the early second trimester, sonographic depiction of the cochlear labyrinth was possible. On coronal imaging, the cochleas showed ringlike echogenic borders containing hypoechoic liquid content. The cochlear modiolus appeared as a central echogenic round spot ("cochlear target sign"). The cochleas were observed caudad to the temporal lobes, separated by the clivus. Shifting of the coronal plane showed progressive coiling of the basal cochlear turn toward the second turn ("cochlear whirlpool sign"). Two-dimensional transvaginal scanning showed at least 1 cochlea in 79% (33 of 42) of the cases. Adding 3D multiplanar reconstruction, at least 1 cochlear target sign was observed in 83% (35 of 42). The cochlear whirlpool sign on at least one side was shown in 57% (24 of 42). The maximal cochlear diameter was measured in fetuses with clear cochlear margin visualization. In this subgroup, the mean gestational age ± SD was 15.8 ± 0.5 weeks, and the mean maximal cochlear diameter was 6.4 ± 0.8 mm. CONCLUSIONS: Prenatal sonographic inner ear depiction was previously considered impossible. Using a unique time window in the early second trimester, we achieved feasible fetal cochlear imaging.