Advanced multiparametric magnetic resonance imaging of multinodular and vacuolating neuronal tumor.

BACKGROUND AND PURPOSE: Multinodular and vacuolating neuronal tumor (MVNT) of the cerebrum is a rare brain lesion with suggestive imaging features. The aim of our study was to report the largest series of MVNTs so far and to evaluate the utility of advanced multiparametric magnetic resonance (MR) techniques. METHODS: This multicenter retrospective study was approved by our institutional research ethics board. From July 2014 to May 2019, two radiologists read in consensus the MR examinations of patients presenting with a lesion suggestive of an MVNT. They analyzed the lesions' MR characteristics on structural images and advanced multiparametric MR imaging. RESULTS: A total of 64 patients (29 women and 35 men, mean age 44.2 ± 15.1 years) from 25 centers were included. Lesions were all hyperintense on fluid-attenuated inversion recovery and T2-weighted imaging without post-contrast enhancement. The median relative apparent diffusion coefficient on diffusion-weighted imaging was 1.13 [interquartile range (IQR), 0.2]. Perfusion-weighted imaging showed no increase in perfusion, with a relative cerebral blood volume of 1.02 (IQR, 0.05) and a relative cerebral blood flow of 1.01 (IQR, 0.08). MR spectroscopy showed no abnormal peaks. Median follow-up was 2 (IQR, 1.2) years, without any changes in size. CONCLUSIONS: A comprehensive characterization protocol including advanced multiparametric magnetic resonance imaging sequences showed no imaging patterns suggestive of malignancy in MVNTs. It might be useful to better characterize MVNTs.

Multinodular and Vacuolating Posterior Fossa Lesions of Unknown Significance.

Multinodular and vacuolating neuronal tumor of the cerebrum is a rare supratentorial brain tumor described for the first time in 2013. Here, we report 11 cases of infratentorial lesions showing similar striking imaging features consisting of a cluster of low T1-weighted imaging and high T2-FLAIR signal intensity nodules, which we referred to as multinodular and vacuolating posterior fossa lesions of unknown significance. No relationship was found between the location of the lesion and clinical symptoms. A T2-FLAIR hypointense central dot sign was present in images of 9/11 (82%) patients. Cortical involvement was present in 2/11 (18%) of patients. Only 1 nodule of 1 multinodular and vacuolating posterior fossa lesion of unknown significance showed enhancement on postcontrast T1WI. DWI, SWI, MRS, and PWI showed no malignant pattern. Lesions did not change in size or signal during a median follow-up of 3 years, suggesting that multinodular and vacuolating posterior fossa lesions of unknown significance are benign malformative lesions that do not require surgical intervention or removal.

Pyridoxine-dependent epilepsy: A novel mutation in a Tunisian child.

Pyridoxine-dependent epilepsy (PDE) is a rare autosomal recessive metabolic disease characterized by seizures in neonates or infants, which is unresponsive to antiepileptic drugs but controlled by pyridoxine. Without prompt treatment, continued seizures and severe encephalopathy result. Mutations in the ALDH7A1 gene encoding α-amino-adipic semialdehyde (α-AASA) dehydrogenase (antiquitin) have been identified as the cause of PDE. We report on a novel ALDH7A1 mutation in a Tunisian child with PDE.

Infantile and childhood onset PLA2G6-associated neurodegeneration in a large North African cohort.

BACKGROUND AND PURPOSE: Mutations in the PLA2G6 gene are causative of PLA2G6-associated neurodegeneration (PLAN), a spectrum of neurodegenerative conditions including infantile, childhood and adult onset forms. METHODS: Seventeen North African patients with a clinical suspicion of infantile-onset PLAN underwent clinical, neurophysiological and neuroimaging examinations, and PLA2G6 sequencing. Haplotype analysis was performed to date the identified founder mutation. RESULTS: All patients carried biallelic mutations in PLA2G6. Sixteen children had the commonest form of infantile-onset PLAN, with early onset of psychomotor regression, hypotonia, pyramidal and cerebellar signs, and abnormal ocular movements. The phenotype was highly homogeneous, with rapid development of severe spastic tetraparesis, cognitive impairment and optic atrophy. Neuroimaging showed cerebellar atrophy and claval hypertrophy to be the commonest and earliest signs, whilst cerebellar cortex hyperintensity and pallidal iron deposition were later findings. Motor or sensory-motor neuropathy and electroencephalogram fast rhythms were also frequent. Nine patients from six families shared the same founder mutation (p.V691del) which probably arose by the late seventeenth century. Only one patient fitted the diagnosis of the much rarer childhood-onset PLAN. Despite the early onset (18 months), clinical progression was slower, with behavioral disturbances and dystonia. Typical features of infantile-onset PLAN such as hypotonia, nystagmus/strabismus, optic atrophy, electroencephalogram fast rhythms and motor neuropathy were absent. Cerebellar atrophy, claval hypertrophy and pallidal hypointensity were evident at brain magnetic resonance imaging. This patient carried a missense variant predicted to be less deleterious. CONCLUSIONS: The PLAN-associated phenotypes and the challenges of diagnosing the childhood-onset form are delineated, and a common North African founder mutation is identifed.

[Nonketotic hyperglycemia-induced hemiballism]. / Hémiballisme secondaire à une hyperglycémie sans cétose.

Nonketotic hyperglycemia-induced hemichorea or hemiballism is a well-recognized entity that is rarely encountered. Particular computed tomography and magnetic resonance imaging findings have been described. The pathophysiological mechanism of this disease remains uncertain. We report here on two female patients that presented with hemiballism secondary to nonketotic hyperglycemia and underwent brain computed tomography and magnetic resonance imaging.

Feasibility of dynamic MRI for evaluating velopharyngeal insufficiency in children.

OBJECTIVE: To demonstrate the feasibility of dynamic MRI with near-real-time temporal resolution for analysing velopharyngeal closure. METHODS: Eleven children and young adults (seven girls, four boys, mean age: 8.4 years) with suspected velopharyngeal insufficiency (VPI), and one healthy volunteer underwent MRI (1.5 Tesla) using T2 fast imaging sequences. Imaging was done without any sedation at rest and during various phonations in the axial and sagittal planes. Images were analysed by two radiologists, a plastic surgeon and a speech therapist. RESULTS: The MRI examinations were well tolerated by even the youngest patient. A qualitative analysis found that the sagittal dynamic sequences during phonation were in relation to the clinical data in all patients. A quantitative analysis enabled calculation of the elevation angle of the soft palate in relation to the hard palate, the velar eminence angle and the percentage of reduction of the antero-posterior diameter of the pharyngeal lumen. CONCLUSION: Dynamic MRI is a non-invasive, rapid and repeatable method. It can be considered a complementary tool to endoscopy and fluoroscopy, particularly in children, for assessing VPI without any sedation or radiation exposure.

[Transarterial embolization of intracranial dural arteriovenous malformations with ethylene vinyl alcohol copolymer (Onyx18): report of three cases]. / Embolisation par voie artérielle de malformations artérioveineuses durales intracrâniennes à l'aide d'éthylvinyl alcool copolymère (Onyx((R))18) : à propos de trois observations.

BACKGROUND: This is a report of the endovascular treatment of three intracranial dural arteriovenous malformations (DAVM) using Onyx. PATIENTS AND METHODS: We analyzed the clinical and angiographic results in three patients with intracranial DAVM, revealed by a hemorrhagic event and treated by endovascular way by the use Onyx. Angiographic investigation showed the DAVM to be located in the lateral sinus in two cases and in the tentorium region in the third. RESULTS: In all three cases, embolization was performed by selective catheterization of the meningeal arterial feeder of the DAVM. The injection of Onyx resulted in complete anatomical exclusion of the DAVM, as demonstrated by posttreatment angiography. Clinically, the patients recovered partially or completely their neurological deficit. CONCLUSION: Onyx is a liquid embolization agent recently introduced for the treatment of DAVM. When used under optimal conditions, it offers a feasible alternative option in the treatment of such vascular malformations.

Intramedullary neurenteric cyst without concurrent malformation.

Neurenteric cysts (NECs) are dysraphic lesions. They are usually extramedullary, the intramedullary forms are very rare. To our knowledge, only 10 cases of isolated intramedullary NECs have been reported. We report a case of intramedullary NEC without any associated dysraphic lesion. The clinical findings were: cervical pain and left hemicorporal weakness which predominated at the upper limb. Neuroradiological evaluation was performed by means of MRI which revealed a cystic lesion at C3-C4 level. A partial excision was performed and the diagnosis of NEC was established by histological study.

Reversible metronidazole-induced encephalopathy.

We report the neuroimaging findings of a case of reversible metronidazole-induced encephalopathy. Magnetic resonance imaging (MRI) demonstrated lesions in highly suggestive locations. Follow-up imaging performed 1 month after cessation of metronidazole therapy demonstrated resolution of imaging findings.

Atypical CT and MRI aspects of an epidermoid cyst.

We report a case of an unusual epidermoid cyst (EC) of the cerebellopontine angle that appeared hyperdense on computed tomography (CT) scanning, hyperintense on T1-weighted MR images and hypointense on T2-weighted magnetic resonance (MR) images. Diffusion-weighted imaging showed a hypointense lesion. We discuss imaging characteristics of ECs, explain the atypical findings in our case and confirm that the signal seen on diffusion-weighted images in the EC is related to a T2 effect.