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Brain imaging plays a key role in accurately identifying abusive head trauma (AHT). An exact and rapid diagnosis is needed due to the extreme severity of AHT, since there is a risk of neurological sequelae and potentially fatal recurrence. Several medical specialists will work collaboratively to detect and confirm abuse in children: the radiologist has a leading role in this approach. This article describes the most common neuro-imaging patterns of AHT, including extra axial, intra axial, bony, and ligamentous lesions, with a special focus on the dating issue and the differential diagnosis.

Stroke remains the leading source of long-term disability. As the only direct descending motor pathway, the corticospinal tract (CST) is the primary pathway to innervate spinal motor neurons and one of the most well studied tracts in human neuroanatomy. Its clinical significance can be demonstrated in many distinguished traumatic situations and diseases such as stroke. Along‐tract statistics analysis enables the extraction of quantitative diffusion metrics along specific white matter fiber tracts. Besides quantitative metrics derived from classical diffusion tensor imaging (DTI), such as fractional anisotropy and diffusivities. In this study, we extracted DTI derived quantitative microstructural diffusion metrics along the CST tract in patients with moderate to severe subacute stroke. Respectively DTI metric of individual patient's fiber tract was then plotted. This approach may be useful for future studies that may compare in two different time (acute and chronic). The contribution of this work presents a totally computerized method of DTI image recognition based on conventional neural network (CNN) in order to supply quantitative appraisal of clinical characteristics. The obtained results have achieved an important classification (Accuracy=94.12%) when applying the CNN. The proposed methodology enables us to assess the classification of the used DTI images database within a reduced processing time. Experimental results prove the success of the proposed rating system for a suitable analysis of microstructural diffusion when compared to previous work.

Mitochondrial cytopathies, among which the Leigh syndrome (LS), are caused by variants either in the mitochondrial or the nuclear genome, affecting the oxidative phosphorylation process. The aim of the present study consisted in defining the molecular diagnosis of a group of Tunisian patients with LS. Six children, belonging to five Tunisian families, with clinical and imaging presentations suggestive of LS were recruited. Whole mitochondrial DNA and targeted next-generation sequencing of a panel of 281 nuclear genes involved in mitochondrial physiology were performed. Bioinformatic analyses were achieved in order to identify deleterious variations. A single m.10197G>A (p.Ala47Thr) variant was found in the mitochondrial MT-ND3 gene in one patient, while the others were related to autosomal homozygous variants: two c.1412delA (p.Gln471ArgfsTer42) and c.1264A>G (p.Thr422Ala) in SLC19A3, one c.454C>G (p.Pro152Ala) in SLC25A19 and one c.122G>A (p.Gly41Asp) in ETHE1. Our findings demonstrate the usefulness of genomic investigations to improve LS diagnosis in consanguineous populations and further allow for treating the patients harboring variants in SLC19A3 and SLC25A19 that contribute to thiamine transport, by thiamine and biotin supplementation. Considering the Tunisian genetic background, the newly identified variants could be screened in patients with similar clinical presentation in related populations.

Multiple Sclerosis (MS) is a chronic autoimmune disease that affects the central nervous system. It is characterized by the appearance of inflamed lesions. The diagnosis, as well as the prognosis of these lesions, are considered as tedious tasks and time consuming. The objective of this paper is to propose an automated method allowing to assist and detect MS lesions in 3D MRI acquisition. A deep learning network based on the Detectron-2 model has been used. The proposed model involves three main steps: preprocessing, feature extraction and MS detection. A database of 4500 images was acquired from the National Institute of Neurology Mongi Ben Hmida of Tunisia and was preprocessed in order to train the model. In the prognosis stage, chaotic features extracted from the segmented lesions are used in order to define pertinent clinical characteristics that will help neurologists to predict lesions progression in the majority of complicated cases. In the diagnosis stage, the proposed deep model achieves an average detection accuracy of 98% by evaluating the result on healthy and pathological images. Automatic segmentation results show that our proposed method has the ability to segment MS lesions with an average accuracy of 96.4%.

The extent and the location of the multiple sclerosis plaques in the MR image of the brain are important criteria for the prognosis and diagnosis. The segmentation of lesions by manual delineation is extremely difficult and a tedious task due to observer variability, in addition to anatomical variability between subjects. In multiple sclerosis, lesions segmentation has become a crucial criterion, for this reason, automated lesion segmentation and evaluation are not only desirable with regard to time and cost-effectiveness but also constitute a necessary condition to minimize user bias. In this contribution, we propose an automatic method for lesions delineation based on MR images. In this approach, 3D FLAIR-weighted, with 3 Tesla magnetic field, is used to image lesions in the white matter while segmenting the brain tissue. Our approach allows the automatic identification of these lesions. Our results are validated quantitatively with the public database “BrainWeb”, “ISBI2015”, MICCAI2008, and “MICCAI2016.”

Hypomyelination and congenital cataract (HCC) is characterized by congenital cataract, progressive neurologic impairment, and diffuse myelin deficiency. This autosomal recessive disorder is caused by homozygous variant in the FAM126A gene. Five consanguineous Tunisian patients, belonging to three unrelated families, underwent routine blood tests, electroneuromyography, and magnetic resonance imaging of the brain. The direct sequencing of FAM126A exons was performed for the patients and their relatives. We summarized the 30 previously published HCC cases. All of our patients were carriers of a previously reported c.414 + 1G > T (IVS5 + 1G > T) variant, but the clinical spectrum was variable. Despite the absence of a phenotype–genotype correlation in HCC disease, screening of this splice site variant should be performed in family members at risk.

We present an illustrative case of pediatric intracranial anaplastic ganglioglioma and systematically reviewed the current reported data of anaplastic ganglioglioma in the pediatric population.A comprehensive literature search for our review was conducted using PubMed, Scopus, Web of Science, PsycINFO, Cochrane, and Embase databases. The search terms included "ganglioglioma," "anaplastic," "pediatrics," "children," and "intracranial." We used no limitations for date, type, or language. Reports of pediatric patients (age19 years) with intracranial anaplastic gangliogliomas were included. Baseline patient demographic characteristics, clinical presentations, imaging characteristics, management strategies, and outcomes data were extracted.We included 24 studies involving 34 patients in the quantitative synthesis. The mean patient age was 9.18 ± 5.46 years (range, 0.16-18). A male predominance was observed (approximate male/female ratio, 1.61:1). Increased intracranial pressure was the most common symptom (n = 19; 55%), followed by seizures (n = 11; 32%). These tumors were most often found in the supratentorial compartment (n = 26; 76%). All 34 patients had undergone surgical removal. The mean follow-up was 22.2 months (range, 2-72). The mean overall survival duration was 43 months (95% confidence interval, 32.45%-55.31%; 1- and 3-year overall survival, 76.6% and 45.5%, respectively). The median event-free survival was 34 months (95% confidence interval, 10.6%-57.3%; 1- and 3-year event-free survival rate, 76.6% and 42.4%, respectively).Our results contribute to our understanding of the characteristics of this rare malignant tumor and show that anaplastic ganglioglioma should be considered in the differential diagnosis of intracranial tumors in pediatric patients.

Aim: Cavernous sinus tumours represent 1% of all intracranial neoplasms, and 41% of them are cavernous sinus meningiomas (CSM). The disappointing results of the microsurgical approach in the treatment of CSM have led to the evaluation of a more conservative strategy, such as conformal radiotherapy (CR) and stereotactic radiosurgery (SRS). Here we report our experience with CR in the treatment of CSM, aiming to evaluate local control, clinical response and radiation-induced toxicity. Methods: A total of 18 patients with CSM, treated from 2011 to 2017, were retrospectively reviewed. Results: Patient median age was 59 years [31–74]. Clinical presentation included impaired vision, cranial nerve deficit, headache, ocular signs. Median tumour size was 35 mm [13–56]. Six patients were operated before the radiation. Twelve patients were treated with definitive radiotherapy. Dose of radiation varied from 50.4 Gy in 28 fractions, to 54 Gy in 30 fractions. Median follow-up was 33 months [6–84]. Among the 18 patients, patient’s signs and symptoms of disease remained unchanged in three cases (16.66%), 12 (66.66%) were improved and 1 patient (5.55%) exhibited tumour progression (exophthalmia). Two patients (11.11%) were lost to follow-up after the end of the treatment with radiotherapy. Findings: Based on our study findings, CR has proved to be a relatively safe and effective therapeutic option in the treatment of CSM, whether used as first-line or as an adjuvant treatment. CR may be particularly effective for tumours that are not amenable to SRS, owing to lesion size (> 30-35 mm) and/or proximity to the optic apparatus (

Journal of Neuroradiology - Sous presse. Epreuves corrigees par l'auteur. Disponible en ligne depuis le lundi 2 aout 2021

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 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.

Introduction RNA polymerase III (Pol III)‐related leukodystrophies are a group of autosomal recessive neurodegenerative disorders caused by mutations in POLR3A and POLR3B. Recently a recessive mutation in POLR1C causative of Pol III‐related leukodystrophies was identified. Methods We report the case of a Tunisian girl of 14 years of age who was referred to our department for evaluation of progressive ataxia that began at the age of 5. Genetic diagnosis was performed by NGS and Sanger analysis. In silico predictions were performed using SIFT, PolyPhen‐2, and Mutation Taster. Results Neurological examination showed cerebellar and tetrapyramidal syndrome, mixed movement disorders with generalized dystonia and severe myoclonus leading to death at 25 years. Brain MRI scans showed diffuse hypomyelination associated with cerebellar atrophy. It also showed bilateral T2 hypointensity of the ventrolateral thalamus, part of the posterior limb of the internal capsule, the substantia nigra and the subthalamic nucleus. Next generation sequencing leukodystrophy panel including POLR3A and POLR3B was negative. Sanger sequencing of the coding regions of POLR1C revealed a novel homozygous mutation. Conclusion The clinical and imaging findings of patients with POLR1C hypomyelinating leukodystrophy are reviewed. Interestingly, severe myoclonic dystonia and T2 hypointensity of the substantia nigra and the subthalamic nucleus are not reported yet and could be helpful for the diagnosis of POLR1C hypomyelinating leukodystrophy.

Multiple sclerosis is a chronic neuro-inflammatory disease. Its diagnosis and evaluation require a visual assessment in brain magnetic resonance images. This neurological disease is characterized by its unpredictable evolution. The most common form is relapsing–remitting multiple sclerosis, consisting of episodes of neurological dysfunction remitting with a variable degree of recovery. The underlying mechanisms are still unknown and have no mathematical models to explain this spatial and temporal dissemination. The main objective of this paper is to propose an approach based on chaos theory to define the clinical characteristics for lesion progression, principally its evolution. Previous authors have explored the nervous system by accurately modeling their attractors in the phase space and reproducing a non-linear result. This remains to be compared with chaotic attributes. In this work, multiple sclerosis lesions are treated through modeling and calculating of their degree of evolution. This is a retrospective study of cases collected from the National Institute of Neurology Mongi Ben Hmida. It included 74 patients with an age group ranging from 20 to 72 years. Four clinical trials are properly discussed: unstable cases with active lesions may be described by dynamic and non-linear systems presenting higher chaos value compared to ill patients with inactive lesions. On the other hand, the accuracy of chaos demonstration can be favorably affected by the reduced resolution of magnetic resonance images. Therefore, the interest is in preprocessing to improve the eventual results. High accuracy was achieved for the models discussed in this paper (91.97–85.1%). Accordingly, the suitability and practical usefulness of the ‘simple’ pretreatment to achieve multiple sclerosis classification are demonstrated.

Background: Squamous cell carcinoma (SCC) is the most common form of nonmelanoma skin cancer after basal cell carcinoma. Simple excision can be the treatment at early stages of diagnosis. However, at late stages, treatment is more complex due to extension to the skull and the dura. In extremely rare cases, it can invade the brain making it a challenging situation for treatment. Case Description: We present the case of a 54-year-old man with a history of cutaneous SCC who presented an invasive left frontal recurrence with brain invasion 19 years after initial surgery. The patient underwent surgery which consisted in tumor removal and bone and skin reconstruction. Immediate and late outcomes were favorable. Conclusion: Multidisciplinary treatment for SCC diagnosed in advanced stages is the best way to obtain encouraging results. Although significant advancements have been made, further study is needed for cases with advanced disease.

Meningiomas are tumors derived from arachnoid cells. More than 90% of cases have a benign clinical course and are classified as grade I according to the World Health Organization. A confrontation between radiologic findings and pathological examination is necessary to predict the grading of meningiomas.To study the radiological presentation by magnetic resonance imaging (MRI) and pathological features of intracranial meningiomas grade I.This was a retrospective descriptive study of a series of 35 cases of grade I meningiomas. A review of MRI images was performed in this study.Our series consisted of 25 female and 10 male patients with a mean age of 49.2 years.The tumor was localized at the base of the skull in 20 cases (57.14%). The average size was 49 mm. At MRI, all meningiomas were solid showing enhancement after injection of contrast agent. This enhancement was homogeneous in 21 cases and heterogeneous in 14 cases. The edema was broad and extended in 15 cases, reduced in 8 cases and absent in 12 cases. The mean minimum apparent diffusion coefficient was 0.77 and the mean maximum average diffusion coefficient was 0,8. On histological examination, the meningioma was of meningotheliomatous type in 23 cases (65.7%), fibroblastic in 8 cases (22.9%), transitional 3 cases (8.6%) and angiomatous in one case (2,8%).Although the final diagnosis of meningioma is mainly based on pathological examination, comparison with imaging is also important to orient the pathologist.

Introduction L’hemiatrophie cerebrale (HAC) est un signe radiologique rare. Elle peut etre congenitale ou acquise. L’imagerie par resonance magnetique represente l’examen de choix pour etablir le diagnostic etiologique. Objectifs Determiner les caracteristiques cliniques et radiologiques des patients ayant une HAC. Patients et Methodes Etude retrospective menee sur 13 ans (2005 a 2017) incluant 7 patients suivis dans notre service et ayant une HAC. Les donnees cliniques, radiologiques et evolutives ont ete recueillies et analysees. Resultats Sept garcons avec un âge moyen de 5,4 ans. Les symptomes revelateurs etaient un retard mental et/ou une epilepsie. Une hemiparesie etait notee dans 5 cas. Les anomalies radiologiques associees etaient une polymicrogyrie ipsilaterale (5 cas), atrophie d’un hemitronc cerebral (3 cas), epaississement de calvaria et calcifications sous-corticales (1 cas), et un angiome leptomeninge (1 cas). Une encephalite de Rasmussen etait retenue dans un cas et un syndrome de Sturge–Weber (SSW) dans 2 cas. Discussion L’HAC se manifeste par une hemiparesie, une epilepsie et un retard mental. Les etiologies sont diverses. Une encephalite de Rasmussen et un SSW etaient retrouves dans notre serie. Une polymicrogyrie ipsilaterale, notee chez 5 de nos patients, etait decrite mais reste rare en cas de SSW. Elle etait retrouvee chez un de nos patients avec SSW. Conclusion L’identification de l’etiologie de l’HAC est importante pour etablir une prise en charge therapeutique adaptee et mieux definir le pronostic.

Mycoplasma pneumoniae is a common cause of respiratory tract infection. Extra-pulmonary complications of M. pneumoniae infection include neurologic complications involving the central nervous system. Myelitis is one of the most severe complications of central nervous system. We report a unique case of acute transverse myelitis associated with M. pneumoniae infection in a 3-year-old boy with particular imaging and clinical course features. Intravenous corticosteroids were prescribed with an 8 wk tapering of oral corticosteroids resulting in full recovery. We postulate an immune-mediated mechanism.

To demonstrate the feasibility of dynamic MRI with near-real-time temporal resolution for analysing velopharyngeal closure. 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. 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. 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.

The pituitary stalk and the posterior pituitary gland are composed of specialized glial cells called pituicytes. Hence, it is understandable that the neurohypophysis can be a host to all of the neoplastic processes that originate from the glial cell series. These primary neurohypophyseal glial tumors are rare. We distinguish astrocytoma, tanycytoma, and granular cell tumor (GCT). Tanycytoma and astrocytomas, which include pituicytoma and pilocytic astrocytoma, are specific to the neurohypophysis, whereas GCT is less specific as it has been described elsewhere in the CNS. In addition, very few cases of neurohypophyseal ependymoma, pleomorphic xanthoastrocytoma, and primitive neuroectodermal tumors have been reported. Pituicytoma, formerly called infundibuloma, is considered grade I glial neoplasm by the 2007 WHO classification. Because it arises from pituicytes, it is highly specific to neurohypophysis. When arising from the infundibulum it is suprasellar, whereas when arising from the posterior lobe or both it is intrasellar. Suprasellar extension may induce optic chiasm and hypothalamus compression. Pituicytoma is seen in adults with a mean age of 50 years, without gender predilection. Only a few cases have been described in children. The main clinical signs are visual impairment, headache, hypopituitarism, and fatigue. Paradoxically, diabetes insipidus is an uncommon symptom in pituicytoma. It can also be incidentally discovered in asymptomatic patients. On MRI, the normal bright spot on T1WI of the posterior pituitary is typically absent. The pituicytoma appears as a solid, well-circumscribed mass with an average size of 16 mm, ranging between 5 and 30 mm. It can be suprasellar, intra- and suprasellar, or, rarely, purely intrasellar in location, with occasional cavernous invasion. This tumor is hyperintense on T2WI, and iso- or hypointense to gray matter on T1WI (Figs. 36.1 and 36.2). The presence of a cystic component is uncommon. After gadolinium administration, the tumor will typically show an intense and homogeneous enhancement (Fig. 36.2). Uncommonly, it will show moderate and heterogeneous enhancement (Fig. 36.1). A nonspecific pre- and postsellar dural enhancement can be seen (Fig. 36.2). When seen, the anterior displacement of the adenohypophysis by the tumor is an affirmative sign suggesting the neurohypophyseal origin (Fig. 36.1). Sellar enlargement, though uncommon, can help to differentiate pituicytoma from pituitary adenoma. Diagnosis may be improved by better morphological characterization but most importantly by clinical correlation (visual impairment and headache without diabetes insipidus). However, the final diagnosis is made by immunohistochemistry and electron microscopy. A total surgical resection is curative, with no recurrence or need for adjuvant therapy. Pituitary pilocytic astrocytoma is indistinguishable from pituicytoma on imaging. The differential diagnosis is made on pathology. Tanycytoma is a hypothalamic–suprasellar tumor that can also involve the pituitary stalk. It is clinically aggressive with a high recurrence rate, and is characterized by its large size. Tumor encasement of the arteries of the circle of Willis with possible infarction, extension beneath the frontal lobes, and third ventricle obstruction are common features in children. Tanycytoma appears hyperintense on T2WI and hypointense on T1WI with cystic and solid components. Intense enhancement of the solid portion is seen after contrast administration. The prognosis in children is worse than in adults. GCT is a rare and benign tumor of the neurohypophysis, considered a WHO grade I glial neoplasm. Previously called granular cell myoblastoma or choristoma, it arises from granular cell type pituicytes, although structurally identical tumors have been described elsewhere in the CNS. This tumor is usually diagnosed in the fifth decade and twice as often in females than in males. In most cases, GCT consists of small nests of tumor cells that do not have any space-occupying effects, and patients are asymptomatic. When symptomatic, symptoms are related to very large size and mass effect. These signs consist of visual disturbances, hypopituitarism, hyperprolactinemia, and headache. The appearance of GCT on MRI is nonspecific, with an enhancing suprasellar or supra- and intrasellar mass which is isointense to gray matter on both T2 and T1 WIs. Homogeneous or heterogeneous but intense enhancement is possible and reflects its high vascularity. Calcifications may be seen. Absence of the normal pituitary bright spot may be a clue that the tumor is of neurohypophyseal origin, but this finding is not specific. Treatment for symptomatic GCT is surgical; postoperative irradiation is controversial. Germ cell tumors are described in Chap. 31.

Both CT scanning and MRI are usually necessary for the complete evaluation of these tumors because of the involvement of both soft tissue and bony structures at the skull base. Chordomas are rare tumors that derive from embryonic remnants of the notochord. Cranial chordomas arise mainly from the clivus and are locally destructive. Clival chordomas represent less than 0.2 % of all intracranial tumors. They can be encountered in all age groups, with a peak in the fourth decade of life. Gender ratio is 2:1 (male/female) and there is no racial predilection. Cranial chordomas most often originate from the spheno-occipital synchondrosis, and thus typically have a midline location. Occasionally chordomas may arise unilaterally in the skull base from the petrous apex. They may spread to sellar and parasellar area, posterior fossa, and nasopharynx. Clinical symptoms depend on the direction of tumor growth. Sellar chordomas usually present with hypopituitarism and chiasmal compression. Parasellar chordomas present with hypopituitarism, oculomotor nerve palsy, and optic tract compression. Purely clival chordomas are characterized by headache, cranial nerve palsy, and brainstem compression. The abducens nerve is the most commonly affected. They usually are locally aggressive and frequently recur, but metastases are very rare. Sarcomatous degeneration and dedifferentiation have been reported. There are three histological subtypes of chordomas: classic, chondroid, and dedifferentiated. Chordomas are characterized by foamy, vacuolated, physaliferous cells within a myxoid stroma, and usually cause extensive bone destruction of the skull base, best analyzed on CT. CT will also show frequent intratumoral sequestered bone fragments. MRI typically shows a destructive invasive soft tissue mass arising from the clivus. At an early stage, bone expansion indicates that the tumor originates from bone and not adjacent structures. The extension of chordomas is primarily posterior, with involvement of the pontine cistern and, occasionally, the premedullary cistern. On MRI, posterior extension may show as a thumb indenting the pons and/or of the medulla (Fig. 37.1). Extension can be upward to the sella turcica, displacing the pituitary gland, downward to the nasopharynx, or laterally to the middle cranial fossa. Most chordomas demonstrate T1 hypointensity and T2 hyperintensity, with suggestive hypointense intratumoral septations (Fig. 37.2). Foci of T1 hyperintensity may be depicted within the tumor or at its periphery, which represent residual bony fragments, calcifications, mucoid material, or hemorrhage (Fig. 37.3). Following gadolinium administration, chordomas usually show lobulated areas with a honeycomb appearance. Enhancement is variable: it can be mild, intense, or absent. Overall, the signal in chordomas is heterogeneous on all sequences on T1 and T2 WIs and after gadolinium administration (Fig. 37.4). Low ADC values have been found in the dedifferentiated histological variant ecchordosis physaliphora, also derived from notochord remnants. Knowledge of this entity is merited because it is considered as a benign congenital malformation and thus differs from chordoma, which is a true tumor. It is usually asymptomatic. Pontine hemorrhage or CSF fistula associated with ecchordosis physaliphora have been reported. Ecchordosis physaliphora is a midline intradural retro-/intraclival lesion inducing a bony clival defect without aggressive features. Its signal is similar to CSF on T2 and T1 WIs with no enhancement after gadolinium infusion (Fig. 37.5). When detected, the bony stalk attachment to the clivus is considered a characteristic sign. It can be seen on CT or on thin high-resolution MR sequences. Chondromas and chondrosarcomas of the skull base are uncommon cartilaginous tumors that develop from embryonic cartilaginous remnants enclosed in the cranial base synchondroses. They most often arise from the petro-occipital synchondrosis and have a lateral location in the parasellar area, at the foramen lacerum level. They may also arise from the spheno-occipital synchondrosis with a midline location. Chondromas of the sella turcica have been reported, for which there is no gender predilection; they are often diagnosed between the third and fourth decade. Chondromas and chondrosarcomas occur at higher frequency in Ollier disease and Maffucci syndrome. The most common presentation symptoms are deficits of the cranial nerves, including the abducens, optic, acoustic-facial, and lower cranial nerves, and headaches. The onset of symptoms is usually gradual. Endocrine dysfunction has been reported in sellar chondromas. On histologic examination, chondromas consist of mature, well-differentiated hyaline cartilage. Total excision is curative, with no recurrence. Chondrosarcomas are malignant tumors composed of atypical chondrocytes, whose nuclei are hyperchromatic and enlarged. There are three histological subtypes of chondrosarcomas, ranging from grade I (well differentiated) to grade III (poorly differentiated). They display chondroid calcifications in more than half of the cases. CT is required to evaluate intratumoral calcification and bone erosion (Fig. 37.6). On MRI, these tumors appear hypointense or isointense on T1WI and heterogeneously brightly hyperintense on T2WI (Fig. 37.7). They enhance poorly in a heterogeneous fashion, with linear and nodular areas (Fig. 37.8). The typical chondroid calcifications are curvilinear and usually appear hypointense on MR spin-echo sequences. However, they may appear hyperintense T1WIs depending on the degree of mineralization. On ADC maps these tumors are usually bright, reflecting high diffusion.

SUMMARY 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.

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.

Introduction Les encephalites limbiques autoimmunes (ELAI) sont sous diagnostiquees chez l’enfant. Les aspects neuroradiologiques de ces affections peuvent etre deroutantes. Objectifs Rapporter les aspects neuroradiologiques des ELAI dans une serie hospitaliere d’enfants tunisiens. Patients et methodes Il s’agit d’une etude retrospective (2004–2016) ayant inclus tous les enfants porteurs d’ELAI confirmee par le dosage d’anticorps correspondant, et suivis au service de neurologie de l’enfant et de l’adolescent (Tunis). Les donnees de l’IRM encephalique ont ete analysees et discutees. Resultats Dix enfants (4 garcons/6 filles) ont ete inclus. L’âge moyen etait de 8 ans. Les crises epileptiques et la deterioration cognitive etaient presentes chez tous les patients. L’IRM encephalique etait anormale dans 7/10 cas: des hypersignaux T2 et FLAIR hippocampiques, des pedoncules cerebelleux, du tronc cerebral et des noyaux gris dans 3/10 cas respectivement. Les anticorps en cause etaient des anti-NMDA (7/10 cas) et des anti-Ma2 (3/10 cas). Discussion Notre cohorte reflete l’heterogeneite neuroradiologique au cours des ELAI. Les hyper signaux T2 et FLAIR au niveau du lobe temporal, representent les anomalies les plus frequentes. L’atteinte de la fosse posterieure chez nos patients est exceptionnelle et assez deroutante. Ces anomalies a l’IRM encephalique sont inconstantes d’ou l’interet de la confrontation clinico-radiologique et la recherche d’anticorps antineuronaux. Conclusion L’elargissement du spectre des ELAI chez l’enfant et leur heterogeneite clinico-radiologique doivent etre pris en consideration afin de reduire l’errance diagnostique et d’optimiser la prise en charge therapeutique.

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.

Introduction La sclerose en plaques (SEP) pseudotumorale est une forme caracterisee par la presence d’une lesion demyelinisante extensive, superieure a 2 cm de diametre. Elle peut mimer toutes sortes de lesions extensives. Observation Un patient âge de 35 ans a consulte pour lourdeur du membre inferieur gauche evoluant depuis 10 jours. Une TDM cerebrale faite en urgence a montre une plage hypodense du centre semi-ovale droit. L’IRM morphologique a montre une lesion frontale droite de 30 mm de grand axe, en hyperignal T2 et FLAIR, hyposignal T1, prenant le contraste de facon annulaire et exercant un leger effet de masse sur le ventricule lateral. L’IRM multimodale a montre en spectroscopie une augmentation du rapport choline/NAA avec presence de lipides et de lactate au sein de la lesion orientant vers une masse neoplasique. Une augmentation du coefficient de diffusion a ete objectivee en sequence de diffusion et la perfusion a montre une rupture de la barriere hemato-encephalique sans hyperperfusion ce qui est en faveur d’une origine inflammatoire. Le patient a recu un traitement corticoide avec amelioration. Une IRM de controle a montre la regression de la lesion avec presence des plusieurs lesions disseminees repondants aux criteres de SEP. Discussion Les formes pseudotumorales (de Balo, de Marburg ou de Schilder) sont des variantes rares de SEP. Leurs aspects morphologiques peuvent mimer des lymphomes ou des gliomes. La spectroscopie, comme le souligne notre observation, peut etre trompeuse. La recherche d’autres lesions et les resultats des explorations electrophysiologiques et biologiques permettent d’eviter des gestes chirurgicaux inutiles aux patients. Conclusion L’IRM multimodale et en particulier la spectroscopie peut induire en erreur a la phase aigue d’une SEP pseudo-tumorale en montrant des anomalies metaboliques similaires a celles d’une lesion tumorale de bas grade.

Introduction L’hemorragie cerebelleuse a distance du site operatoire (HCD) est une complication rare et imprevisible en neurochirurgie, dont les mecanismes physiopathologiques sont encore discutes. Objectifs Le but de notre travail est d’analyser les caracteristiques cliniques, radiologiques et evolutives de l’HCD et de discuter sa physiopathologie. Methodes Nous rapportons trois nouvelles observations d’HCD avec une revue systematique de la litterature. Resultats Trois patients ont ete operes respectivement pour hematome sous dural aigue, meningiome frontal et clippage d’anevrisme de l’artere cerebral anterieure. L’evolution a ete marquee par l’apparition 4 a 6 jours post-operatoires de troubles de la conscience chez deux patients et d’un syndrome d’hypertension intracrânienne chez le troisieme. Le scanner cerebral de controle a montre un hematome cerebelleux hemispherique associe a une hemorragie sous arachnoidienne sous-tentorielle. L’evolution a ete favorable dans les 3 cas. Discussion L’HCD est une complication rare dont l’incidence est estimee de 0,15 a 0,6 % des chirurgies supra-tentorielles. Sa frequence reelle est sous-estimee car elle est souvent asymptomatique. L’aspect radiologique typique constitue le « signe du zebre ». L’hypothese physiopathologique la plus etayee est une hypotension du liquide cephalorachidien. Sa prevention repose donc sur la limitation de la depletion du LCR en per-operatoire. Conclusion L’HCD doit etre suspectee devant un tableau d’hypertension intracrânienne et/ou des troubles de la conscience survenant au decours d’une chirurgie cerebrale.

A 17-year-old girl presented with a 1-month history of right knee pain after repeated strenuous martial art training. She had no medical history. Point tenderness during palpation of the posteromedial aspect of the knee was noted. The rest of the physical examination was within normal limits and laboratory data were entirely normal. Radiography (Fig. 1), ultrasound (Fig. 2), MRI (Fig. 3), and CT (Fig. 4) of the right knee were performed. Based on the history, physical examination, laboratory studies, and imaging studies, what is the differential diagnosis?

The purpose of this article is to identify the typical imaging features of periosteal chondrosarcoma on radiography, CT, and MRI.Periosteal chondrosarcoma is a rare low-grade malignant cartilaginous tumor arising from the external surface of bone. Imaging features are often specific. Recognizing periosteal chondrosarcoma and differentiating it from other surface tumors is of capital importance because the prognosis is excellent after adequate local surgery alone.

Introduction Le syndrome de regression caudale est un syndrome malformatif rare, associant a des degres variables une agenesie des vertebres sacrees et coccygiennes avec un raccourcissement du femur et des anomalies genito-urinaires et cardiovasculaires. Son etiopathogenie demeure inconnue. Le diabete maternel et la predisposition genetique seraient des facteurs etiologiques probables. L’imagerie est la cle du diagnostic positif. Elle est representee par l’echographie en antenatal et par l’imagerie par resonance magnetique (IRM) apres la naissance. Materiel et methodes Etude retrospective incluant deux patientes ayant ete explorees par IRM cerebro-medullaire (3-Tesla). Resultats L’âge de nos patientes etait de 3 et 7 ans. Une patiente avait une derivation ventriculo-peritoneale pour une hydrocephalie. La symptomatologie clinique etait variable associant une encopresie et une enuresie primaire dans un cas et un retard psychomoteur dans un autre cas. L’imagerie par resonance magnetique a permis de poser le diagnostic d’une agenesie caudale chez les deux enfants. Elle a montre egalement une stenose associee de l’aqueduc de Sylvius chez l’une de nos patientes. Conclusion L’IRM est l’examen de choix a realiser en cas de suspicion d’un syndrome d’agenesie caudale. Elle permet d’effectuer un bilan lesionnel complet et precis des differentes malformations vertebrales, medullaires et cerebrales associees.

Dural sinus malformations (DSM) are rare malformations mainly reported after birth. The objectives of this study are to describe their prenatal patterns and to focus on their possible favorable outcome. This multicenter retrospective study reported 13 cases of DSM prenatally diagnosed. The admission criterion was a dural mass posterior to the vermis. In 12 patients, MRI was performed after US. Follow-up in 10 born babies (mean: 8 months) and three neuropathological examinations were available. In all fetuses, DSM presented as a well-delimited round mass involving the torcular. The follow-up examinations (n = 10) revealed progressive thrombosis of the DSM marked by a heterogeneous pattern (US and MRI) with concentric rings. The volume of the mass decreased, with complete regression in seven patients (five before and two after birth). One child died at the age of 5 months in the context of major hydrocephalus and another developed atrophy of the frontal lobes. The eight other babies were doing well (5 days to 3 years) without any treatment (n = 6) or following treatment for hydrocephalus (n = 2). Prenatal DSM may have a typical MR pattern, and the prognosis might not be as bad as has previously been reported. In the absence of criterion to predict the hydrovenous cerebral imbalance, it is mandatory to check the parenchyma and the ventricles during the pregnancy.

Introduction La paralysie brutale du nerf oculomoteur commun est souvent causee par une compression anevrysmale. Cependant, des rares cas de conflit vasculo-nerveux par l’artere cerebrale posterieure ont ete rapportes. Observation Nous rapportons le cas d’une patiente âgee de 45 ans qui s’est presentee pour une diplopie brutale non douloureuse. L’examen neurologique a objective une paralysie isolee du nerf oculomoteur droit. Les sequences conventionnelles de l’IRM cerebrale (3 Tesla) n’ont pas montre d’anomalies. Par contre, la sequence CISS-3D a pu objectiver une compression du nerf oculomoteur commun droit par l’artere cerebrale posterieure homolaterale. Discussion Les conflits vasculo-nerveux comme le cas de notre patiente sont rarement en cause d’une ophtalmoplegie du III. L’IRM constitue l’examen de choix pour le diagnostic etiologique des paralysies oculomotrices. La sequence CISS-3D avec reconstruction multi-planaire en particulier permet d’etudier les rapports entre le segment cisternal du nerf oculomoteur commun et les structures adjacentes, et ainsi guider la procedure chirurgicale. Conclusion L’IRM cerebrale CISS-3D est indispensable dans l’exploration des paralysies oculomotrices afin de detecter les compressions vasculaires non anevrysmales du nerf oculomoteur commun.

Objectifs Demontrer la faisabilite de la cine-IRM avec haute resolution temporelle dans l’analyse de la fonction velo-pharyngee. Materiels et methodes Huit patients (six filles, deux garcons, 520 ans, moyenne 8) atteints d’insuffisance velopharyngee, ainsi qu’un adulte volontaire sain ont ete explores en IRM (1,5 Tesla, Siemens) avec des sequences T2 HASTE et TRUFI. L’imagerie a ete effectuee sans sedation sans et avec phonation (au moins 3 phonemes) dans les plans transversal et sagittal. Les images ont ete interpretees par deux radiologues, un chirurgien plasticien et un orthophoniste. Resultats L’analyse qualitative des sequences dynamiques dans le plan sagittal lors des exercices de phonation confirmait dans tous les cas la mobilite reduite du voile. Celle-ci a ete chiffree par deux parameters variant en fonction des differents phonemes : l’angle de l’eminence velaire par rapport au plan du palais osseux et le pourcentage de reduction du diametre anteroposterieur de la lumiere pharyngee. Conclusion Actuellement, l’evaluation de la fonction velo-pharyngee necessite des examens invasifs (endoscopie) ou irradiants (videofluoroscopie). Cette etude preliminaire montre que l’IRM, non invasive, rapide et reproductible peut evaluer la fonction velo-pharyngee en pediatrie, ce qui est une aide a la decision operatoire. Ceci confirme les rares etudes effectuees chez l’adulte.