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Purpose: This study aimed to assess the feasibility of magnetic resonance (MR) neurography in children, and the potential roles of diffusion-weighted imaging (DWI) and fiber-tracking (FT) techniques., Methods: Five pediatric patients (age range: 6-12 years) underwent magnetic resonance imaging (MRI) for various clinical indications: neurogenic bladder (case 1); persistent hand pain following minor trauma (case 2); progressive atrophy of the lower left extremity muscles (case 3); bilateral hip pain (case 4); and palpable left supraclavicular mass (case 5). All studies were performed using a 1.5-T Avanto MRI scanner (Siemens, Erlangen, Germany). The protocol included 3D T2-weighted STIR and SPACE imaging, T1-weighted fat-saturation post-gadolinium imaging and diffusion tensor imaging (DTI) with tractography. ADC (N×10(-3) mm(2)/s) and FA values were calculated from regions of interest (ROIs) centered on the nerves. Nerve-fiber tracks were calculated using a fourth-order Runge-Kutta algorithm (NeuroD software)., Results: MR neurography allowed satisfactory visualization of all neural structures, and FA and ADC measurements were feasible. The final diagnoses were Tarlov cysts, median-nerve compression, sciatic perineurioma, Charcot-Marie-Tooth disease and plexiform neurofibroma in a patient with NF-1., Discussion: FA and ADC measurements are of little value because of the lack of normal reference values. Nerve-fiber tractography (FT) may be of value in the characterization of tumor pathology, and is also helpful in the planning of surgical treatments., Conclusion: MR neurography is feasible in pediatric patients. However, a considerable amount of work has yet to be done to establish its role in the clinical management of the wide range of peripheral nerve diseases., (Copyright © 2010 Elsevier Masson SAS. All rights reserved.)

Background: Congenital ocular motor apraxia (COMA) occasionally shares with Joubert syndrome (JS) and related disorders (JSRDs) a peculiar malformation, the 'molar tooth sign' (MTS). In JSRDs, the absence of superior cerebellar peduncles (SCP) decussation is reported., Objective: To investigate whether COMA demonstrates similar abnormal axonal pathways., Materials and Methods: Eight healthy age-matched controls, three children with clinical COMA and one child with clinical JSRD underwent examination with a 1.5-T MRI scanner. Diffusion-weighted imaging (DWI), colour-coded fractional anisotropy maps and three-dimensional diffusion tensor imaging (DTI) tractography of the cerebellorubral network were analyzed., Results: On DTI cartography, the 'red dot' originally supposed to represent the SCP decussation in the midbrain was present in controls as well in those with COMA but absent in the single case with JS. In none of the subjects including controls was 3-D FT able to depict the SCP decussation. When seeded, the red dot resulted in the ventral tegmental decussation (VTD). It was normal in controls and in patients with COMA but was absent in our single patient with JSRD. MTS was identified in alla patients with COMA and in the patient with JSRD., Conclusion: MTS can be present in both COMA and JSRD but the underlying anatomy depicted by fibre tracking is distinct. The main difference is the integrity of the VTD in COMA.

Joubert syndrome is a rare autosomal recessive disorder characterized by ataxia, developmental delay, and oculomotor and respiratory abnormalities in relation to cerebellar vermian and midbrain dysgenesis. The midbrain dysgenesis is responsible for the molar tooth sign on axial magnetic resonance imaging (MRI). This classic hallmark of Joubert syndrome has been identified in other disorders sharing overlapping clinical and radiologic features with Joubert syndrome. Recent identification of two different genes points to genetic heterogeneity in this group of disorders, now entitled Joubert syndrome and related disorders, making a genetic prenatal diagnosis not readily available. In addition, fetal ultrasonography lacks sensitivity in regard to posterior fossa malformation. Fetal MRI is now acknowledged as the method of choice to delineate posterior fossa malformation in a fetus. The identification of a molar tooth sign has, however, rarely been documented by a fetal brain MRI. We report a case of Joubert syndrome diagnosed prenatally using fetal MRI. We also discuss the etiology of Joubert syndrome in view of the recent genetic advances and murine models of cerebellar dysgenesis.

Dear Editor, We would like to share a rare clinical experience in a child with trigeminal nerve chronic motor denervation caused by cerebellar peduncle pilocytic astrocytoma. The unilateral weakness of the masticatory muscles with temporal muscle atrophy was related to the long-standing compression of the proximal motor roots of the trigeminal nerve related to compressive mass effect of the tumor before diagnosis. [Extracted from the article]

Background: Herpes simplex virus (HSV) is the most common identified cause of focal encephalitis worldwide. However, postoperative HSV encephalitis (HSVE) is a rare complication of neurosurgical procedures and a significant clinical challenge Method: We describe 3 cases of postoperative HSVE and review all published reports. A total of 23 cases were identified. Discussion: Clinical heterogeneity represents a diagnostic challenge in the postoperative setting. Cerebral magnetic resonance imaging showed typical findings in a minority of patients only, whereas HSV-specific polymerase chain reaction on the cerebrospinal fluid proved to be a valuable test. The postoperative viral pathophysiology remains a subject of debate. The rate of adverse outcome is high and early antiviral treatment seems to be a strong predictor of clinical outcome. Conclusion: We recommend early empirical treatment for any patient presenting with post-neurosurgical lymphocytic meningo-encephalitis, and prophylactic antiviral treatment for patients with a history of previous HSVE who will undergo a neurosurgical procedure. [ABSTRACT FROM AUTHOR]

Severe fetal ventriculomegaly is generally associated with poor prognosis in terms of survival and neurodevelopment outcome. As such, many parents opt to terminate the pregnancy independently of a known etiology.We report here the case of a female fetus with severe progressive ventriculomegaly due to the unexpected presence of bilateral nodular periventricular heterotopias visualized on MRI of a fetal brain. Reaching a structural diagnosis was perceived as a relief for the parents and the pregnancy was continued. Neurodevelopment assessment at 3 years of age is normal with no epilepsy. [ABSTRACT FROM AUTHOR]

Children's cognitive abilities and school achievements are deeply affected by parental socioeconomic status (SES). Numerous studies have reported lower cognitive performance in relation to unfavorable environments, but little is known about the effects of SES on the child's neural structures. Here, we systematically explore the association between SES and brain anatomy through MRI in a group of 23 healthy 10-year-old children with a wide range of parental SES. We confirm behaviorally that language is one of the cognitive domains most affected by SES. Furthermore, we observe widespread modifications in children's brain structure. A lower SES is associated with smaller volumes of gray matter in bilateral hippocampi, middle temporal gyri, left fusiform and right inferior occipito-temporal gyri, according to both volume- and surface-based morphometry. Moreover, we identify local gyrification effects in anterior frontal regions, supportive of a potential developmental lag in lower SES children. In contrast, we found no significant association between SES and white matter architecture. These findings point to the potential neural mediators of the link between unfavourable environmental conditions and cognitive skills. [ABSTRACT FROM AUTHOR]