Enlargement of the Optic Chiasm: A Novel Imaging Finding in Glutaric Aciduria Type 1.

Patients with glutaric aciduria type 1, without early diagnosis and initiation of preventive treatment, often develop movement disorders and various degrees of motor disability due to striatal area-specific damage induced by an acute episode of metabolic decompensation. The neuroimaging phenotype of patients with glutaric aciduria type 1 includes characteristic cyst-like bilateral enlargement of the Sylvian fissures and anterior subarachnoid spaces and signal abnormalities including supratentorial white matter and deep gray matter structure T2 hyperintensities, frequently associated with restricted diffusion. In this retrospective study, we add to the neuroimaging spectrum of glutaric aciduria type 1, a novel imaging finding present regardless of a previous metabolic crisis: the enlargement of the optic chiasm associated with signal abnormalities in the anterior intracranial visual structures observed in 6 of 10 patients. These optic pathway abnormalities are suggested as useful diagnostic clues for glutaric aciduria type 1, and possible pathophysiologic mechanisms are discussed.

Incidence and morphology of the incisive suture in CT scanning of young children and human fetuses.

PURPOSE: Incisive suture is a suture classically described on the oral face of the palate in fetuses and young children. The aim of our study was to describe the evolution of the incisive suture in human fetuses and to evaluate the incidence of this suture in a population of young children under 4 years, to determine if there is a possibility of improving the anterior growth of the maxilla, by stimulation of this suture. METHODS: One hundred and thirty CT scan images of patients aged from birth to 48 months have been studied and nine fetal palates aged from 18 to 26 weeks of development, have been scanned using high-resolution X-ray micro-computed tomography RESULTS: The CT scan images of patients showed that an incisive suture was present in 33/130 cases (25,4%). All the patients with a suture were under 2 years old. The fetal palate study showed that the suture was present in the inferior aspect of the palate (oral cavity) in all cases. The incisive suture increased from 18 to 24 weeks. At 26 weeks it stopped growing although the intercanine length increased. Considering the closure of the suture in a vertical plane, our study on fetuses has shown that the incisive suture is closing from its superior side (nasal side) to its inferior side. CONCLUSIONS: Considering all these results it appears to us that the incisive suture is partially ossified after birth, it cannot be stimulated by orthodontic appliances.

SOX10 mutations mimic isolated hearing loss.

Ninety genes have been identified to date that are involved in non-syndromic hearing loss, and more than 300 different forms of syndromic hearing impairment have been described. Mutations in SOX10, one of the genes contributing to syndromic hearing loss, induce a large range of phenotypes, including several subtypes of Waardenburg syndrome and Kallmann syndrome with deafness. In addition, rare mutations have been identified in patients with isolated signs of these diseases. We used the recent characterization of temporal bone imaging aspects in patients with SOX10 mutations to identify possible patients with isolated hearing loss due to SOX10 mutation. We selected 21 patients with isolated deafness and temporal bone morphological defects for mutational screening. We identified two SOX10 mutations and found that both resulted in a non-functional protein in vitro. Re-evaluation of the two affected patients showed that both had previously undiagnosed olfactory defects. Diagnosis of anosmia or hyposmia in young children is challenging, and particularly in the absence of magnetic resonance imaging (MRI), SOX10 mutations can mimic non-syndromic hearing impairment. MRI should complete temporal bones computed tomographic scan in the management of congenital deafness as it can detect brain anomalies, cochlear nerve defects, and olfactory bulb malformation in addition to inner ear malformations.

Simplified gyral pattern in severe developmental microcephalies? New insights from allometric modeling for spatial and spectral analysis of gyrification.

The strong positive-allometric relationship between brain size, cortical extension and gyrification complexity, recently highlighted in the general population, could be modified by brain developmental disorders. Indeed, in case of brain growth insufficiency, the pathophysiological relevance of the "simplified gyral pattern" phenotype is strongly disputed since almost no genotype-phenotype correlations have been found in primary microcephalies. Using surface scaling analysis and newly-developed spectral analysis of gyrification (Spangy), we tested whether the gyral simplification in groups of severe microcephalies related to ASPM, PQBP1 or fetal-alcohol-syndrome could be fully explained by brain size reduction according to the allometric scaling law established in typically-developing control groups, or whether an additional disease effect was to be suspected. We found the surface area reductions to be fully explained by scaling effect, leading to predictable folding intensities measured by gyrification indices. As for folding pattern assessed by spectral analysis, scaling effect also accounted for the majority of the variations, but an additional negative or positive disease effect was found in the case of ASPM and PQBP1-linked microcephalies, respectively. Our results point out the necessity of taking allometric scaling into account when studying the gyrification variability in pathological conditions. They also show that the quantitative analysis of gyrification complexity through spectral analysis can enable distinguishing between even (predictable, non-specific) and uneven (unpredictable, maybe disease-specific) gyral simplifications.

[Audiophonological evaluation of 16 children fitted with cochlear implants for sensorineural hearing loss induced by bacterial meningitis]. / Implants cochléaires dans les surdités après méningite bactérienne: suivi audiologique de 16 enfants.

BACKGROUND: Bacterial meningitis (BM) is the primary etiology of acquired sensorineural hearing loss (SNHL) in children and may compromise language development. Since the 1990 s, cochlear implants (CIs) have become part of the management of children with profound SNHL with encouraging results. The aim of this study was to analyze the audiophonological performance of children before and after cochlear implantation for SNHL following bacterial meningitis. METHODS: Retrospective study of all children fitted with CIs for bilateral severe to profound SNHL after bacterial meningitis in the Robert-Debré pediatric ENT department between August 1990 and March 2009. Audiophonological performance was assessed using the APCEI profile. RESULTS: Of the 283 children receiving implants during that period, 16 children (6%; 6 boys, 10 girls) underwent CI implantation after bacterial meningitis (Streptococcus pneumoniae in 8 cases, Neisseria meningitidis in 2 cases, and Haemophilus influenzae in 4 cases). The mean time from meningitis to SNHL was 8.3 months (median, 1.5 months; range, 1 day to 13 years). The mean time from meningitis to cochlear implantation was 2 years and 3 months (median, 7 months; range, 1 month to 13 years 3 months). Twelve children (75%) presented partial cochlear and/or vestibular ossification on presurgical CT scan. Three children received bilateral implants. DISCUSSION: Thirteen children (81%) developed early SNHL in the first 3 months, whereas 3 children developed SNHL more than 10 months after meningitis. As for the benefits of cochlear implantation, 11 children presented near to normal intelligibility and optimal use of their cochlear implant; 5 children presented partial benefits due to neurological sequelae (1), a long delay before implantation (1), technical problems (2), or a social problem in relation to low socioeconomic status (1). CONCLUSION: After bacterial meningitis, audiological evaluation must be made carefully during the first 3 months to detect early SNHL, but SNHL may also develop several years later. In case of profound SNHL and a modified signal of the labyrinth on the MRI, cochlear implantation must be performed without delay before cochlear and/or vestibular ossification. Cochlear implantation is an effective technique with good long-term audiologic results. The coexistence of neurological lesions may compromise the results, but it should not contraindicate a cochlear implantation.

Spectrum of temporal bone abnormalities in patients with Waardenburg syndrome and SOX10 mutations.

BACKGROUND AND PURPOSE: Waardenburg syndrome, characterized by deafness and pigmentation abnormalities, is clinically and genetically heterogeneous, consisting of 4 distinct subtypes and involving several genes. SOX10 mutations have been found both in types 2 and 4 Waardenburg syndrome and neurologic variants. The purpose of this study was to evaluate both the full spectrum and relative frequencies of inner ear malformations in these patients. MATERIALS AND METHODS: Fifteen patients with Waardenburg syndrome and different SOX10 mutations were studied retrospectively. Imaging was performed between February 2000 and March 2010 for cochlear implant work-up, diagnosis of hearing loss, and/or evaluation of neurologic impairment. Eleven patients had both CT and MR imaging examinations, 3 had MR imaging only, and 1 had CT only. RESULTS: Temporal bone abnormalities were bilateral. The most frequent pattern associated agenesis or hypoplasia of ≥1 semicircular canal, an enlarged vestibule, and a cochlea with a reduced size and occasionally an abnormal shape, but with normal partition in the 13/15 cases that could be analyzed. Three patients lacked a cochlear nerve, bilaterally in 2 patients. In addition, associated abnormalities were found when adequate MR imaging sequences were available: agenesis of the olfactory bulbs (7/8), hypoplastic or absent lacrimal glands (11/14), hypoplastic parotid glands (12/14), and white matter signal anomalies (7/13). CONCLUSIONS: In the appropriate clinical context, bilateral agenesis or hypoplasia of the semicircular canals or both, associated with an enlarged vestibule and a cochlear deformity, strongly suggests a diagnosis of Waardenburg syndrome linked to a SOX10 mutation.

[Computed tomography of the normal and pathologic temporal bone]. / Anatomie tomodensitométrique de l'oreille normale et malformée.

High-resolution computed tomography scanning (CT) allows depiction of microanatomic structures of the temporal bone. CT is useful for detecting several pathologic conditions of the temporal bone such as congenital malformations, particularly in young children with sensorineural hearing loss. Some external, middle and inner ear structures are difficult to evaluate. The objective of this study has been to provide the key planes in coronal and axial planes (five coronal planes and three axial planes) but also with oblique planes reconstruction (two planes) for normal temporal bones evaluation. These standardized planes help to improve visualization of the main congenital malformations. Identification of obvious morphogenetic malformations (Michel aplasia, Mondini deformity….) is not difficult. However, less severe dysplasia may be missed or normal micro anatomic structures in newborn misreaded.

Early-onset hyperargininaemia: a severe disorder?

UNLABELLED: Hyperargininaemia is a rare inborn error of metabolism due to a defect in the final step of the urea cycle. Infantile onset is the most common presentation with recurrent vomiting and psychomotor delay associated with spastic paraparesis; chronic hyperammonaemia is often overlooked. Neonatal and early-onset presentations are very uncommon and their clinical course not well-described. We report on a 3-week-old hyperargininaemic girl who presented with neurological deterioration associated with liver failure and 47-day ammonia intoxication before diagnosis could be made and treatment started. Despite appropriate but delayed treatment, our patient exhibited severe psychomotor delay at age 1 year. CONCLUSION: Early identification and management of this rare but potentially treatable affection is crucial as delayed management may result in poor neurological outcome.

[Mitochondrial neurogastrointestinal encephalomyopathy]. / Encéphalopathie myoneurogastro-intestinale.

This paper describes MRI aspects of a leukodystrophy due to the Mitochondrial Neurogastrointestinal Encephalomyopathy syndrome in an adolescent girl investigated for nocturnal recurrent emesis leading to major cachexia.

Familial CHARGE syndrome because of CHD7 mutation: clinical intra- and interfamilial variability.

CHARGE syndrome (OMIM #214800) is a multiple malformation syndrome with distinctive diagnostic criteria, usually because of CHD7 (chromodomain helicase DNA binding 7) haploinsufficiency. Familial occurrence of CHARGE syndrome is rare. We report six patients from two Caucasian families (both with one parent and two children) affected by mild to severe CHARGE syndrome. Direct sequencing of the CHD7 gene was performed in these two unrelated families. A mutation in exon 8 (c.2501C>T - p.S834F) in first chromodomain was found in family A and a nonsense mutation in exon 2 (c.469C>T - p.R157X) in family B. Both mutations are de novo in the parents. In family A, the elder son had bilateral cleft lip and palate, esophageal atresia with fistula, complex heart defect and vertebral abnormalities, while the younger had a posterior coloboma. Their mother had asymptomatic vestibular dysfunction and retinal coloboma, identified after the molecular diagnosis of her children. In family B, both affected children had severe expression of CHARGE syndrome. The father carrying the mutation only had asymmetric anomaly of the pinnae. These familial reports describe the intrafamilial variability of CHARGE syndrome, and underline the presence of CHD7 mutations in patients who do not fit the 'classical clinical criteria' for CHARGE syndrome.

[The deaf child: anatomy, etiologies and management]. / Le sourd est un enfant: qu'est-ce que ça change. Anatomie, pathologie, prise en charge.

Temporal bone imaging in children shows radioanatomical aspects and diseases distinct from the imaging and pathology results found in adults. Imaging modalities such as CT and MR bring out these differences. The aim of this study is to present the CT and MR particularities of the temporal bone during postnatal growth. The mastoid air cells form mostly in the postnatal period and the course of pneumatization is directly correlated with middle ear successive inflammatory episodes. The most frequent etiologies of hearing loss in children are reviewed, emphasizing their specificities in clinical presentation, radiological aspects, and treatment. In children, conductive hearing loss with normal tympanic membrane is mostly caused by minor aplasia rather than otosclerosis. Sensorineural hearing loss, even when unilateral, is predominantly due to malformation or infection and in rare cases to posterior fossa tumor.

[Imaging aspects of sphenoid during development]. / Aspects en imagerie du sphénoïde au cours de la croissance.

To show the different steps of ossification and pneumatization of the sphenoid bone in children in order to emphasize normal anatomic variations. CT scanners and MRI studies of children up to 15 year old performed for various craniofacial conditions, without suspected involvement on cranial growth, are presented. The normal process of the ossification, of the closure of the synchondroses and of the pneumatization is demonstrated. Some examples of congenital abnormalities are also shown. The knowledge of these normal steps and variations is essential, in order to properly evaluate traumatic or congenital situations, but is also helpful for the diagnosis of bone dysplasias and bone marrow diseases (tumor or hematologic disorders).

The petrosquamosal sinus: CT and MR findings of a rare emissary vein.

BACKGROUND AND PURPOSE: Morphologic changes in the dural sinuses and emissary veins of the posterior fossa relate closely to the development of the brain. We report characteristic findings of imaging in six patients with a rare and forgotten emissary vein called the petrosquamosal sinus (PSS). METHODS: From a larger group of patients with ear abnormalities, we selected six patients from three ENT imaging centers, because they had CT features suggestive of a PPS. This was the criterion for inclusion in this retrospective study. They were explored by high-resolution CT (HRCT) of the temporal bone. MR venography was performed in three patients to determine the presence and patency of the emissary vein. RESULTS: The PPS was bilateral in two patients and unilateral in the other four. It affected mainly the left side (left:right ratio, 5:3). Three patients had associated inner ear (n = 2) or middle ear malformations (n = 1). Five of six patients had jugular vein hypoplasia, with development of emissary mastoid veins in three patients. CONCLUSION: Petrosquamosal sinus can be identified on HRCT in a typical location. It is encountered more frequently in patients referred for congenital abnormalities of the skull base. This rare anatomic variant should be assessed before surgical treatment, because proper identification of these large venous channels would be of interest to the surgeon.