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Objects: Tectocerebellar dysraphism was first described by Padget and Lindenberg, together with occipital encephaloceles, cerebellar midline defects, tectal beaking, posterior kinked and displaced brainstem, and inverted cerebellum. We present a unique case of lipoencephalocele associated with tectocerebellar dysraphia and discuss the etiologies of both pathologies. The importance of the developmental comprehension of posterior fossa malformations is stressed. Case report: A 9-month-old girl in good health was referred for a huge occipital mass. On local examination, the patient had a rounded mass about 10×12cm in size, covered by alopecic skin, with a small eccentric dimple without any discharge. Magnetic resonance imaging revealed a lipoencephalocele with an intra- and an extracranial part, associated with tectocerebellar dysraphia with no aspect of inverted cerebellum as originally described in the tectocerebellar dysraphia. Resection of the extracranial part of the lipoma was performed for esthetic reasons. The intracranial part remained in situ. Conclusion: The association of lipoencephalocele and tectocerebellar dysraphia is extremely rare. The functional prognosis seems to be less severe for this combination than for the isolated tectocerebellar dysraphia. This association favors the dysraphic theory for the embryogenesis of the lipoma. It seems safe to restrict the surgery of this bizarre malformation to its external part

The four symptoms composing Gerstmann's syndrome were postulated to result from a common cognitive denominator (Grundstörung) by Gerstmann himself. He suggested that it is a disorder of the body schema restricted to the hand and fingers. The existence of a Grundstörung has since been contested. Here we suggest that a common psychoneurological factor does exist, but should be related to transformations of mental images rather than to the body schema. A patient (H.P.) was studied, who presented the four symptoms of Gerstmann's syndrome in the absence of any other neuropsychological disorders. MRI showed a focal ischaemic lesion, situated subcortically in the inferior part of the left angular gyrus and reaching the superior posterior region of T1. The cortical layers were spared and the lesion was seen to extend to the callosal fibres. On the basis of an extensive cognitive investigation, language, praxis, memory and intelligence disorders were excluded. The four remaining symptoms (finger agnosia, agraphia, right-left disorientation and dyscalculia) were investigated thoroughly with the aim of determining any characteristics that they might share. Detailed analyses of the tetrad showed that the impairment was consistently attributable to disorders of a spatial nature. Furthermore, cognitive tests necessitating mental rotation were equally shown to be impaired, confirming the essentially visuospatial origin of the disturbance. In the light of this report, the common cognitive denominator is hypothesized to be an impairment in mental manipulation of images and not in body schema.

During development in utero of the human brain, an error in one or more of the orderly processes of neuroblast proliferation and differentiation, neuroblast migration and cortical organization may result in disordered neocortical development. Nowadays, the consequent malformations of the cerebral cortex and associated structures are detectable on pre- and postnatal examination with growing frequency, thanks to the evolution of modern imaging modalities. In particular, magnetic resonance imaging (MRI), due to its excellent contrast differentiation and multiplanar capabilities as well as the development of even newer techniques, such as diffusion tensor imaging and spectroscopy, has surpassed all other forms of imaging for the thorough exploration and analysis of congenital anomalies of the central nervous system. These malformations comprise a heterogeneous group of conditions in terms of both the timing and etiology of the developmental aberration as well as the resulting morphological phenotype, including epilepsy, developmental delay/intellectual disability and focal neurological deficits. This study briefly presents some typical examples of congenital malformations of cortical development of the human brain that are encountered in practice. It is our belief that familiarity with the MRI presentations of these conditions can be of considerable value for adequate disease management and genetic counseling.

Imaging plays an essential role for the detection and analysis of pathologic conditions of the brachial plexus. Currently, several new techniques are used in addition to conventional 2D MR sequences to study the brachial plexus: the 3D STIR SPACE sequence, 3D heavily T2w MR myelography sequences (balanced SSFP=CISS 3D, True FISP 3D, bFFE and FIESTA), and the diffusion-weighted (DW) neurography sequence with fiber tracking reconstruction (tractography). The 3D STIR sequence offers complete anatomical coverage of the brachial plexus and the ability to slice through the volume helps to analyze fiber course modification and structure alteration. It allows precise assessment of distortion, compression and interruption of postganglionic nerve fibers thanks to the capability of performing maximum intensity projections (MIP) and multiplanar reconstructions (MPRs). The CISS 3D, b-SSFP sequences allow good visualization of nerve roots within the spinal canal and may be used for MR myelography in traumatic plexus injuries. The DW neurography sequence with tractography is still a work in progress, able to demonstrate nerves tracts, their structure alteration or deformation due to pathologic processes surrounding or located along the postganglionic brachial plexus. It may become a precious tool for the understanding of the underlying molecular pathophysiologic mechanisms in diseases affecting the brachial plexus and may play a role for surgical planning procedures in the near future.

This article provides an overview of the imaging findings of diseases affecting the optic nerve with special emphasis on clinical-radiological correlation and on the latest technical developments in MR imaging and CT. The review deals with congenital malformations, tumors, toxic/nutritional and degenerative entities, inflammatory and infectious diseases, compressive neuropathy, vascular conditions and trauma involving the optic nerve from its ocular segment to the chiasm. The implications of imaging findings on patient management and outcome and the importance of performing high-resolution tailored examinations adapted to the clinical situation are discussed.

Crossed cerebellar diaschisis in patients with epilepsy are uncommon. This case reports a patient with refractory partial seizures who developed hemicerebellar involvement contralateral to an insular epileptogenic focus. The diaschisis was assessed with arterial spin-labeling, a recently developed non-invasive magnetic resonance perfusion sequence.

Summary Introduction We illustrate here the most common MRI artifacts found on routine 3 T clinical neuroradiology that can simulate pathology and interfere with diagnosis. Materials and methods Our group has worked with a 3-T Magnetom Trio (Siemens, Erlangen, Germany) system for two years, with 50% of our time devoted to clinical work and 50% dedicated to research; 65% of the clinical time is dedicated to neuroradiology (2705 patients) and the remaining time to whole-body MRI. We have detected these artifacts during our case readings and have selected the most representative of each type to illustrate here. Results We have observed magnetic susceptibility artifacts (29%), pulsation artifacts (57%), homogeneity artifacts (3%), motion artifacts (6%), truncation artifacts (3%) and, finally, artifacts due to poor or inadequate technique in the examined region. Conclusion High-field imaging offers the benefit of a higher signal-to-noise ratio, thus making possible the options of a higher imaging matrix, thinner slices, the use of spectroscopy and diffusion tensor imaging in the routine clinical neuroradiology with a reduction in time spent. It is vital to be able to recognize these artifacts in everyday practice as they can mimic pathological appearances, thus causing diagnostic errors that could lead to unnecessary treatment. Indeed, most of these artifacts could be avoided with an adequate technique.

Summary Objectives To demonstrate the use of perfusion CT in patients presenting with a suspected diagnosis of stroke to avoid the administration of inappropriate thrombolytic therapy in stroke-mimicking conditions such as status epilepticus. Material and methods We reviewed the imaging studies of four patients presenting with symptoms suggestive of stroke, but finally diagnosed with status epilepticus. Imaging was by a 16-section multidetector CT scanner using a protocol consisting of non-contrast CT, CT angiography and perfusion CT. Color-coded maps allowed calculation of the CBV (cerebral blood volume), CBF (cerebral blood flow) and MTT (mean transit time). Results In all four cases, perfusion CT revealed increases in CBF and CBV as well as a decreased MTT, consistent with hyperperfusion linked to status epilepticus with focal deficit—in contrast to the hypoperfusion observed in stroke patients. Conclusion The use of perfusion CT accurately detected hyperperfusion in status epilepticus presenting as stroke. In such cases, perfusion CT imaging avoided the administration of potentially harmful thrombolytic therapy to patients experiencing seizures due to different underlying etiologies.

The PTEN hamartoma tumor syndrome, manifestations of which include Cowden disease and Bannayan-Riley-Ruvalcaba syndrome, is caused by various mutations of the PTEN gene located at 10q23. Its major criteria are macrocephaly and a propensity to develop breast and thyroid cancers as well as endometrial carcinoma. Minor diagnostic criteria include hamartomatous intestinal polyps, lipomas, fibrocystic disease of the breasts, and fibromas. Mutations of PTEN can also be found in patients with Lhermitte-Duclos disease (dysplastic gangliocytoma of the cerebellum). The authors report the case of a 17-year-old girl who had a severe cyanotic cardiac malformation for which surgery was not advised and a heterozygous missense mutation (c.406T>C) in exon 5 of PTEN resulting in the substitution of cysteine for arginine (p.Cysl36Arg) in the protein, which was also found in her mother and sister. The patient presented in the pediatric emergency department with severe spastic paraparesis. A magnetic resonance imaging study of the spine showed vertebral hemangiomas at multiple levels, but stenosis and compression were maximal at level T5-6. An emergency T5-6 laminectomy was performed. The decompression was extremely hemorrhagic because the rapid onset of paraparesis necessitated prompt treatment, and there was no time to perform preoperative embolization. The patient's postoperative course was uneventful with gradual recovery. This represents the first report of an association of a PTEN mutation and multiple vertebral angiomas. The authors did not treat the remaining angiomas because surgical treatment was contraindicated without previous embolization, which in itself would present considerable risk in this patient with congenital cyanotic heart disease.

Resume Objectifs La prise en charge des lesions traumatiques du plexus du brachial depend essentiellement de la localisation pre- (avulsion radiculaire) ou postganglionnaire (atteinte des troncs et faisceaux) des lesions. L'objectif de cette etude etait de determiner la valeur diagnostique et pronostique de l'IRM dans le bilan lesionnel du plexus brachial traumatique et de correler les resultats de l'imagerie aux donnees cliniques et electroneuromyographiques (ENMG) precoces et tardives. Materiel et methode Neuf patients presentant des lesions traumatiques du plexus brachial ont ete explores par IRM et ENMG a la phase aigue. Un controle a distance a egalement ete realise chez cinq patients. Le protocole IRM comprenait des sequences en FSE T2 et STIR. Les images ont ete interpretees independamment par deux radiologues seniors. Les resultats ont ensuite ete valides en concertation pluridisciplinaire entre chirurgiens, radiologues et neurologues afin de determiner la localisation exacte des lesions ainsi que le mecanisme en cause. L'apport et les limites de chaque technique ont egalement ete precises. Resultats Parmi les neuf patients, l'IRM etait jugee normale chez trois patients alors que l'ENMG montrait des lesions distales chez deux d'entre eux. Chez trois patients, les sequences STIR retrouvaient des hypersignaux etendus de C5 a T1 des troncs et des faisceaux avec persistance des anomalies de signal a trois mois chez un patient et regression partielle des anomalies chez les deux autres. Chez les trois derniers patients, les sequences 3DT2 montraient la presence d'avulsions radiculaires, en concordance avec les donnees de l'ENMG initiale. Conclusion L'IRM est l'examen de choix pour detecter les avulsions radiculaires. En revanche, l'IRM ne permet pas d'apprecier et de localiser les lesions tres distales du plexus contrairement a l'ENMG. La differenciation entre œdeme (atteinte reversible) et demyelinisation (atteinte irreversible) des lesions postganglionnaires necessite une IRM tardive ou des examens complementaires type ENMG.

Aim: Can monovoxel magnetic resonance spectroscopy (MRS) reliably follow tumour progression in low-grade glioma? Materials and Methods: 21 patients with low-grade glioma underwent at least 3 MRS. Results: For progression from a grade II to grade III tumour, a sensitivity of 57.1% and specificity of 60% were observed, with a positive predictive value (PPV) of 48.8% and a negative predictive value (NPV) of 54.5%. For progression under treatment, we obtained a sensitivity of 57.1% by N-acetylaspartate (NAA)/choline (Cho) and myoinositol/creatine (Cr) and a specificity of 100% by Cho/Cr and lipids, with a PPV of 80% and a NPV of 63.6%. Conclusion: We found that NAA/Cho is the best marker of tumour progression before therapy, with a sensitivity of 53.9%. For the therapeutic response, sensitivity was only 28.2%.

Progressive multifocal leucoencephalopathy (PML), a demyelinating disease caused by the JC virus (JCV), occurs in immunosuppressed patients and carries a poor prognosis. A favourable outcome is reported in two patients with PML and dermatomyositis. Immunosuppressive drugs were stopped in patient 1 but could only be partially tapered in patient 2. The JCV-specific CD8+ T cell response was strong in patient 1 and weak in patient 2. Both were treated with cytosine-arabinoside, and patient 2 was also treated with mirtazapine, a 5HT2A receptor antagonist. Combination of these drugs might be helpful to treat HIV-negative patients with PML.

Brain aging affects an increasing segment of the population and the role of chronic cerebrovascular disease is considered to be one of the main parameters involved. For this purpose we compared retrospectively MRI data with digitized subtraction angiography (DSA) data in a group of 50 patients focusing onto the watershed area of the carotid artery vascular territories. In order to evaluate the presence of white matter lesions (WML) in the hemispheric watershed areas, coronal fluid-attenuated inversion-recovery or axial T2 weighted MRI images of patients with symptomatic cerebrovascular insufficiency areas were compared with the capillary phase of DSA studies in anterior-posterior projection. Presence of cerebrovascular occlusive disease was evaluated on DSA using North American symptomatic carotid endarterectomy trial criteria and including evaluation of collateral vascular supply. Pathological MRI findings in the region of the watershed territories correlated overall in 66% of cases with a defect or delayed filling on DSA. In the case of asymmetrical MRI findings, there was a pathological finding of the capillary phase in the watershed area in 92% of DSA studies. Hypoperfusion in the capillary phase of the watershed area as seen on DSA correlated with the stenosis degree of the concerned carotid artery. Our findings suggest that asymmetrical findings of WML in the watershed areas as seen on MRI are caused by hemodynamic effect and a differentiation between small vessel disease and a consequence of distant stenosis may be possible under such conditions.

The purpose of this study was to evaluate the potential of high quality computed tomographic angiography (CTA) to replace digital subtraction angiography (DSA) in cases of ruptured saccular aneurysms and perform early surgical clipping or coiling on the basis of CTA alone. In a prospective study, 100 patients with aneurysmal subarachnoid haemorrhage (SAH) diagnosed by computed tomography underwent CTA. CTA revealed a total of 118 aneurysms including all ruptured aneurysms. A decision of direct surgical clipping, endovascular coiling or therapeutic abstention was made in 89 cases (89%) on the basis of CTA alone. Sixty-one direct surgical procedures were performed after CTA. Twenty-six cases underwent DSA for immediate endovascular treatment of the ruptured aneurysm. In 11 cases (11%), a DSA was performed prior to the therapeutic decision because of unclear aneurysm. Four cases were not treated because of initial poor clinical grade. The surgical findings were compared with CTA data and were considered accurate in all but one case. All patients underwent postoperative DSA within 10 days after SAH. The sensitivity and the specificity of CTA for the detection of all aneurysms, as compared with postoperative DSA, were 95.1 and 100%, respectively. A total of six unruptured aneurysms were missed initially, but were visible retrospectively on CTA in all but one case and were found in patients with multiple aneurysms in whom the ruptured aneurysm was detected by CTA. Current quality CTA allows reliable pretreatment planning for the majority of cases of aneurysmal subarachnoid haemorrhage and diminishes the pretreatment evaluation time critically. Complementary pretreatment DSA is required in situations where CTA characteristics of the ruptured aneurysm is unsatisfactory.

We report an 18-month-old girl with rapidly progressive subacute sclerosing panencephalitis, whose non immunised mother had measles at the time of delivery. The patient presented with repetitive episodes of myoclonic jerks of the head and arms, followed by a drop of head and trunk with frequent falls. EEG, CSF studies and MRI confirmed the diagnosis. Despite therapy with isoprinosine and valproate, seizure activity continued and she became vegetative within 2 months, with severe spasticity and swallowing difficulties, and died at the age of 28 months. Early age of onset and rapid progression were most likely related to haematogenous in utero acquisition of the measles virus prior to delivery, as well as immaturity of neuronal and immune systems. Conclusion: this case emphasises the importance of a high measles vaccine coverage in the population in order to prevent the risk of disease in general and, in particular, gestational measles.

Objective: To determine the volumes of subcortical nuclei in patients with chronic epilepsy. Background: Animal and human data suggest a crucial role for subcortical structures in the modulation of seizure activity, mostly as seizure-suppressing relays. Although cortical epileptogenic foci can vary in localization and extent, it nevertheless appears that these structures subsequently influence seizure propagation in a universal fashion. There is, however, little knowledge about the size of implicated subcortical structures in patients with epilepsy. Method: Using high-resolution MRI, the volumes of selected subcortical nuclei, such as the thalamus, caudate nucleus, putamen, and pallidum, were measured in both hemispheres of 27 patients with temporal lobe epilepsy. Fourteen healthy volunteers served as controls. Statistical analysis was done for both normalized volumes (by total brain volume) and unnormalized volumes. Results: Overall, the patient group had smaller thalamic and striatal volumes in both hemispheres, mostly ipsilateral to the epileptic focus. No significant correlations were noted between volume measurements and age, age at onset, duration of epilepsy, or total seizure frequency, including frequency of generalized seizures. The putamen and thalamus seemed to be affected predominantly in patients with a history of febrile convulsions, whereas patients without febrile convulsions had smaller caudate nuclei bilaterally. Conclusions: Volumetric measurements of subcortical nuclei reveal atrophy of distinct subcortical nuclei in the patient group, predominantly ipsilateral to the focus. This finding probably reflects persistent abnormalities and not secondary change. In addition, the structural differences between patients with and patients without previous febrile convulsions suggest that these conditions may have different causes.

Because of its large spectrum of clinical manifestations, diagnosis of cerebral venous thrombosis may be very difficult. Since appropriate treatment influences prognosis, early recognition of this condition is extremely important. We report a subarachnoid hemorrhage as a rare initial manifestation of cerebral venous thrombosis. A 58-year-old woman was admitted with severe headache of sudden onset, neck stiffness, dysarthria, and ataxia. Computed tomography scan showed a subarachnoid hemorrhage in the right posterior fossa. Magnetic resonance imaging coupled with magnetic resonance angiography revealed right transverse/sigmoid sinus thrombosis with hemorrhagic infarction of the right cerebellar hemisphere leading to a pseudotumoral appearance and displacing the fourth ventricle. Anticoagulant treatment resulted in rapid clinical recovery and in resolution of the radiological signs of infarction and of the subarachnoid and subdural hemorrhages.

The aim of this study was to describe the various MRI features, in correlation to surgical and pathological findings, in patients who presented with pituitary apoplexy (PA). Eleven patients presenting with PA, were evaluated with various MR protocols including spin-echo (SE) T1-weighted sequences in 9 of 11 patients, post gadolinium SE T1-weighted sequences in only 8 of 11 patients, and with T2-weighted SE sequences in 2 of 11 patients. All patients had transsphenoidal pituitary surgery after MR studies. The severity of presenting symptoms ranged from headaches to coma. Ten patients had pituitary macroadenoma; one had a non-hemorrhagic metastatic lesion into a non-adenomatous pituitary gland. Of the 11 patients, one was studied at the acute stage of PA (1 day after onset), 9 at the subacute period (3-15 days after onset), and one at the late stage (5 months after onset). Images compatible with intratumoral hemorrhage were found in all macroadenomas, whereas the metastatic pituitary lesion did not show evidence of bleeding. All gadolinium-enhanced studies showed partial tumoral enhancement. The SE T2-weighted studies demonstrated areas of low and high signal intensities in keeping with the presence of blood degradation contents. Pituitary apoplexy present with different MR features, including hemorrhagic and non-hemorrhagic characteristics on T1-weighted images. Gadolinium-enhanced images do not provide complementary diagnostic information when the presence of blood is assessed on plain images.

PURPOSE: To evaluate eight different diagnostic criteria to help detect neoplastic invasion of laryngeal cartilage at computed tomography (CT). MATERIALS AND METHODS: In a prospective series, 111 patients with carcinoma of the larynx or hypopharynx underwent thin-section, contrast material-enhanced CT before total or partial laryngectomy. The following CT criteria were evaluated: extralaryngeal tumor, sclerosis, tumor adjacent to nonossified cartilage, serpiginous contour, erosion or lysis, obliteration of marrow space, cartilaginous blowout, and bowing. Histologic findings were correlated with findings on CT scans obtained at each level. RESULTS: Histologically, 122 of 412 cartilages were invaded. Depending on the diagnostic criteria and each specific cartilage, there was great variation in sensitivity (7%-83%) and specificity (40%-100%). Sclerosis was the most sensitive criteria in all cartilages but often corresponded to reactive inflammation in the thyroid cartilage. Extralaryngeal tumor and erosion or lysis yielded the highest specificity. Tumor adjacent to nonossified cartilage, serpiginous contour, and obliteration of marrow space were specific although not sensitive signs of invasion in the arytenoid and cricoid cartilage and were nonspecific in the thyroid cartilage. Blowout and bowing were not useful. Selection of the appropriate combination of criteria enabled an overall sensitivity of 91% (associated specificity, 68%) or an overall specificity of 79% (associated sensitivity, 82%). CONCLUSION: Detection of neoplastic cartilage invasion with CT greatly depended on the appropriate use of individual and combined CT criteria.

This report describes techniques and protocols implemented at the Geneva Canton University Hospitals (HUG) for the combination of various biomedical imaging modalities and sensors including electromagnetic tomography, to study, assess, and localize neurological (dys) function. The interest for this combination stems from the broad variety of information brought out by (functional) magnetic resonance imaging, magnetic resonance spectroscopy, computed tomography, single-photon emission tomography, positron emission tomography, and electromagnetic tomography. Combining these data allows morphology, metabolism, and function to be studied simultaneously, the complementary nature of the information from these modalities becoming evident when studying pathologies reflected by metabolic or electrophysiologic dysfunctions. Compared with other current multimodality approaches, the one at the HUG is totally compatible with both clinical and research protocols, and efficiently addresses the multidimensional registration and visualization issues. It also smoothly integrates electrophysiology and related data as fully featured modalities.

Langerhans cell histiocytosis (LCH) with multiple organ involvement is a rare disorder in adults. Extrapituitary involvement of the central nervous system (CNS) is uncommon. We report the unusual case of a 55-year-old woman presenting with a left-sided hemiataxia-hemiparesis, left hemisensory loss and short-lasting episodes of an alien left hand due to lesions of the internal capsule and the right thalamus, extending into the mesencephalon associated with extensive surrounding edema, without pituitary involvement. The neuroradiological image suggested glioblastoma multiforme. Brain biopsy revealed inflammatory tissue and "pseudotumoral" multiple sclerosis was suspected. Biopsy of concomitant lung and bone lesions disclosed Langerhans cell histiocytosis. The treatment with pulsed steroids in association with mycophenolate mofetil led to a sustained, clinical neurological remission.

The corpus callosum is the largest white matter structure in the brain, consisting of 200-250 million contralateral axonal projections and the major commissural pathway connecting the hemispheres of the human brain. The pathology of the corpus callosum includes a wide variety of entities that arise from different causes such as congenital, inflammatory, tumoural, degenerative, infectious, metabolic, traumatic, vascular and toxic agents. The corpus callosum, or a specific part of it, can be affected selectively. Numerous pathologies of the corpus callosum are encountered during CT and MRI. The aim of this study is to facilitate a better understanding and thus treatment of the pathological entities of the corpus callosum by categorising them according to their causes and their manifestations in MR and CT imaging. Familiarity with its anatomy and pathology is important to the radiologist in order to recognise its disease at an early stage and help the clinician establish the optimal therapeutic approach.

Diffusion tensor imaging (DTI) techniques demonstrated diffuse bilateral temporal and extra-temporal abnormalities of white matter in patients presenting mesial temporal lobe epilepsy with hippocampal sclerosis (HS). The aim of this study was to assess these diffusion changes following temporal lobe surgery, by applying a novel voxel-based tract-based spatial statistics (TBSS) technique for whole-brain analysis of fractional anisotropy (FA) and mean diffusivity (MD). Second, region-of-interest analysis (ROI) was performed to improve statistical power.The study included 22 patients with unilateral HS. Twelve patients underwent temporal lobe surgery. Follow up MRI was done in a mean interval of 4 months. Voxelwise pre-operative FA asymmetry in all 22 patients was assessed within subjects between lesional and contralateral hemispheres. The whole-brain post-operative dataset of 10 seizure-free patients was compared with the corresponding pre-operative dataset using voxel-wise statistical analysis. Additionally, regional analysis at the fornices was done with skeleton-based region of interest (SROI).Within a mean interval time of 6.3 months after surgery, 10 of 12 patients were seizure free (83.3%). The voxelwise comparison between lesional and contralateral hemispheres was consistent with previous studies showing a more widespread diffusion alteration in the lesional hemisphere. Voxel-wise comparison between post and pre-operative dataset did not show supra-thresholded voxels. SROI statistical analysis showed significant decrease in FA and increase in MD in the ipsilateral fornix. Significant increase in FA was observed in the contralateral fornix after surgery.The ipsi-lesional fornix showed decreased FA and increased MD after surgery, consistent with Wallerian degeneration. In contrast, contra-lesional fornix demonstrated increase in FA. This observation is important for our understanding of the fate of the remaining brain tissue following removal of an epileptic focus. Postoperative increase in FA may reflect structural reorganization in response to epilepsy surgery. The discrepancy between SROI and voxelwise statistics emphasizes the difference of statistical sensitivity between voxelwise and ROI analyses.

Patient de sexe masculin âge de 22 ans sans antecedent particulier, qui decrit avoir presente a plusieurs reprises depuis environ 6 jours avant l’hospitalisation, des cephalees au niveau occipital puis holocephaliques. Les douleurs sont nonpulsatiles, sans phono-photophobie avec des nausees et soulagement transitoire apres vomissement, sans fievre, ni frisson, ni raideur nucale et sans lateralisation ; toute cette symptomatologie est precedee de douleurs abdominales. Le patient ne presentait ni d’apraxie ni aphasie, etait oriente dans le temps et dans l’espace. La stereognosie et la graphesthesie etaient dans la norme. Il n’y avait pas de signe de Lhermitte. L’equilibre et la demarche etaient normale. Parmi les facteurs de risques cardiovasculaires nous pouvons citer le tabagisme et la consommation d’alcool reguliere. Un bilan de la coagulation a ete demande qui etait dans la norme ainsi qu’un Doppler pour detection d’embole qui demontre la presence d’un foramen ovale permeable. Vu la persistance de la symptomatologie, un angio CT cerebral est realise en urgence. Le scanner cerebral montrait une stenose segmentaire et importante du tiers moyen du tronc basilaire et de la partie distale de l’artere vertebrale droite, sans lesion atheromateuse associee ni autre anomalie (fig. 1a) . Une resonance magnetique cerebrale et des arteres renales a ete realisee comme complement du bilan un mois plus tard. La resonance magnetique cerebrale realisee comportait les sequences morphologiques habituelles (FSE T2 axiale, SE T1 axiale, FLAIR coronale, diffusion axiale) et des sequences angiographiques 3DTOF du polygone de Willis et 3D des troncs supra-aortiques apres injection d’un bolus de produit de contraste. Les deux sequences angiographiques (avec et sans produit de contraste) montraient une disparition de la stenose du tronc basilaire et de l’artere vertebrale (fig. 1b) , constatees sur l’angio CT, ce qui parlait en faveur d’une migraine basilaire associee a un vasospasme sans lesion ischemique.

Summary Introduction Magnetic resonance imaging (MRI) is required for the investigation of surgically intractable epilepsy. In addition to the standard MRI techniques, perfusion sequences can be added to improve visualization of underlying pathological changes. Arterial spin-labeling (ASL) MRI perfusion does not require contrast administration and, for this reason, may have advantages in these patients. Methods We report here on 16 patients with epilepsy who underwent MRI of the brain with ASL and positron emission tomography (PET). Results Despite a slightly reduced resolution with ASL, we found a correlation between ASL, PET and electrophysiological data, with hypoperfusion on ASL that corresponded with hypoperfusion on interictal PET. Conclusion Given the correlation between ASL and PET and electrophysiology, perfusion with ASL could become part of the standard work-up in patients with epilepsy.

Among 504 cases of AIDS diagnosed between 1983 and 1990, there were 86 patients (17%) with toxoplasma encephalitis (TE). All were symptomatic at the time of diagnosis. General signs such as fever, neck stiffness, or headache were present in 87.2%, and 75.6% had focal signs. The primary means of diagnosis was computerized tomographic scanning, revealing 169 lesions of which 80% were immediately contrast-enhancing. All patients had IgG antibodies against Toxoplasma gondii either before (74 of 75 evaluable patients) or at the time of diagnosis of TE (73 of 75). Elevated antibody titers were present in 44% of evaluable patients, compared to 11% of patients with AIDS and other opportunistic infections. Initial treatment was pyrimethamine plus sulfonamides in 65 patients, and pyrimethamine plus clindamycin in 12 patients, with other combinations or no treatment accounting for the remainder. Life-table analysis of the time to discontinuation of treatment because of suspected side effects suggested that sulfadiazine was significantly more toxic, with 48% of patients experiencing an interruption in treatment after 30 days, than pyrimethamine (12%) or clindamycin (24%). The 30-day mortality rate was 12%, and median survival was 310 days after diagnosis, 530 in patients treated with zidovudine and 190 days in those not so treated. Of 82 evaluable patients, 16 relapsed once and 4 of these more than once. The risk of relapse was 27% 1 year after diagnosis of a first episode of TE.

Introduction: The objective of this study was to assess the feasibility and potential clinical applications of diffusion tensor imaging (DTI) and tractography in the normal and pathologic brachial plexus prospectively. Methods: Six asymptomatic volunteers and 12 patients with symptoms related to the brachial plexus underwent DTI on a 1.5T system in addition to the routine anatomic plexus imaging protocol. Maps of the apparent diffusion coefficient (ADC) and of fractional anisotropy (FA), as well as tractography of the brachial plexus were obtained. Images were evaluated by two experienced neuroradiologists in a prospective fashion. Three patients underwent surgery, and nine patients underwent conservative medical treatment. Results: Reconstructed DTI (17/18) were of good quality (one case could not be reconstructed due to artifacts). In all volunteers and in 11 patients, the roots and the trunks were clearly delineated with tractography. Mean FA and mean ADC values were as follows: 0.30 ± 0.079 and 1.70 ± 0.35mm2/s in normal fibers, 0.22 ± 0.04 and 1.49 ± 0.49mm2/s in benign neurogenic tumors, and 0.24 ± 0.08 and 1.51 ± 0.52mm2/s in malignant tumors, respectively. Although there was no statistically significant difference in FA and ADC values of normal fibers and fibers at the level of pathology, tractography revealed major differences regarding fiber architecture. In benign neurogenic tumors (n = 4), tractography revealed fiber displacement alone (n = 2) or fiber displacement and encasement by the tumor (n = 2), whereas in the malignant tumors, either fiber disruption/destruction with complete disorganization (n = 6) or fiber displacement (n = 1) were seen. In patients with fiber displacement alone, surgery confirmed the tractography findings, and excision was successful without sequelae. Conclusion: Our preliminary data suggest that DTI with tractography is feasible in a clinical routine setting. DTI may demonstrate normal tracts, tract displacement, deformation, infiltration, disruption, and disorganization of fibers due to tumors located within or along the brachial plexus, therefore, yielding additional information to the current standard anatomic imaging protocols

Mild influenza-associated encephalitis/encephalopathy with a reversible splenial lesion is a rare entity recently reported almost exclusively in Asiatic individuals. Hallmarks of this clinical-radiological syndrome include severe encephalopathy at onset, prompt and complete recovery, minimal to absent pleocytosis and rapidly reversible involvement of the splenium of the corpus callosum. We report herein a young Caucasian child who in addition had cerebellar involvement and presented a transient mutism during the recovery phase.

OBJECTIVE: To evaluate the prognostic accuracy of combining perfusion CT (PCT) and thrombolysis in brain ischemia (TIBI) ultrasonographic grade in the triage of stroke patients who will benefit from thrombolysis and in predicting the clinical outcome. METHODS: We conducted a prospective study of all consecutive stroke patients admitted to our hospital from March 2003 to July 2007, presenting with signs of acute stroke within the therapeutic window, who had undergone either intravenous or combined intravenous and intra-arterial thrombolysis. All patients were evaluated by a complete stroke CT protocol, transcranial color-coded duplex sonographic monitoring, follow-up imaging (CT or MRI) and clinical outcome at 3 months, as assessed by the modified Rankin scale (mRS). RESULTS: A total of 34 patients were included with a mean NIHSS on admission of 14.2. This study revealed that PCT had 95% sensitivity and 71% specificity in the evaluation of therapy benefit as well as 75% sensitivity and 39% specificity in predicting clinical outcome. The extent of ischemic tissue according to PCT and TIBI grade were significantly correlated (p2) in 18 patients. CONCLUSION: PCT was the most accurate predictor of both thrombolytic therapy benefit and clinical outcome. The TIBI score was useful for determining whether or not to perform intravenous therapy alone or as a combined therapy.

Major progress has recently been made in the neuro-imaging of stroke as a result of improvements in imaging hardware and software. Imaging may be based on either magnetic resonance imaging (MRI) or computed tomography (CT) techniques. Imaging should provide information on the entire vascular cervical and intracranial network, from the aortic arch to the circle of Willis. Equally, it should also give information on the viability of brain tissue and brain hemodynamics. CT has the advantage in the detection of acute hemorrhage whereas MRI offers more accurate pathophysiological information in the follow-up of patients.

Alexander disease is a rare neurodegenerative disorder. its most frequent subtype, the infantile form, is characterized by an early onset and a rapid neurological deterioration during the first months of life. Since the publication of cerebral radiological criteria in 2001, the disease has often been recognized by magnetic resonance imaging (MRI) findings. We report the case of a girl who at the age of 3 months presented with partial seizures and a normal neurological examination. MRI revealed the presence of a periventricular rim, extensive frontal white matter abnormalities, abnormalities of the basal ganglia and thalami and contrast enhancement involving optic chiasm, fornix, hypothalamus and mamillary bodies, corresponding to four of the five reported MRI criteria for Alexander disease. Additional MRI abnormalities not described so far were also observed. The diagnosis was confirmed by genetic analysis. This case illustrates that diagnostic MRI abnormalities of Alexander disease may be present at a very young age, long before the appearance of characteristic clinical signs. Early diagnosis by MRI allows prompt counselling of families. (C) 2009 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved

Imaging of the trigeminal nerve requires a thorough understanding of its anatomy and function, clinical symptoms related to malfunction, and its key pathologies. Because of the nerve's long course from the brainstem nuclei to the peripheral branches, MR imaging and CT studies have to cover a large anatomic area while providing high-resolution images. Although MR imaging has almost completely replaced CT as the diagnostic modality of choice for investigating trigeminal neuropathy, CT still plays a role in the assessment of skull base foramina and facial skeleton. In this article, the clinical, radiologic, and pathologic features of the most common conditions causing trigeminal nerve dysfunction at each specific anatomic level are discussed.

We report the case of a 10-year-old boy with pharmacoresistant epilepsy, symptomatic of a right temporoparietal hemorrhagic lesion, who displayed an eating passion as described for the gourmand syndrome (GS) in adults and discuss the role of epilepsy in GS. This patient presented with a significant change in his eating habits (abnormal preoccupation with the preparation and eating of fine-quality food) concordant with the onset of his seizure disorder, without any previous history of eating disorders or psychiatric illness. This observation corroborates the important role of the right cerebral hemisphere in disturbed eating habits, including the relatively benign GS, and, possibly rarely, in less benign eating disorders such as anorexia and obesity.

Diffusion tensor imaging (DTI) can visualize the white matter tracts in vivo. The aim of this study was to assess the clinical utility of DTI in patients with diseases of the spinal cord. Fourteen subjects underwent magnetic resonance imaging of the spine at 1.5 T. Preliminary diagnosis of the patients suggested traumatic, tumorous, ischemic or inflammatory lesions of the spinal cord. In addition to T2-weighted images, DTI was performed with the gradients in 30 orthogonal directions. Maps of the apparent diffusion coefficient and of fractional anisotropy were reconstructed. Diffusion tensor imaging showed a clear displacement and deformation of the white matter tracts at the level of the pathological lesions in the spinal cord. This capability of diffusion tensor imaging to reliably display secondary alterations to the white matter tracts caused by the primary lesion has the potential to be of great utility for treatment planning and follow-up.

This technical note demonstrates the relevance of the isotropic 3D T2 turbo-spin-echo (TSE) sequence with short-term inversion recovery (STIR) and variable flip angle RF excitations (SPACE: Sampling Perfection with Application optimized Contrasts using different flip angle Evolutions) for high-resolution brachial plexus imaging. The sequence was used in 11 patients in the diagnosis of brachial plexus pathologies involving primary and secondary tumors, and in six volunteers. We show that 3D STIR imaging is not only a reliable alternative to 2D STIR imaging, but it also better evaluates the anatomy, nerve site compression and pathology of the plexus, especially to depict space-occupying tumors along its course. Finally, due to its appropriate contrast we describe how 3D-STIR can be used as a high-resolution mask to be fused with fraction of anisotropy (FA) maps calculated from diffusion tensor imaging (DTI) data of the plexus.

To report a retrospective series of 84 cerebral developmental venous anomalies (DVAs), focusing on associated parenchymal abnormalities within the drainage territory of the DVA. DVAs were identified during routine diagnostic radiological work-up based on magnetic resonance imaging (MRI) (60 cases), computed tomography (CT) (62 cases) or both (36 cases). Regional parenchymal modifications within the drainage territory of the DVA, such as cortical or subcortical atrophy, white matter density or signal alterations, dystrophic calcifications, presence of haemorrhage or a cavernous-like vascular malformation (CVM), were noted. A stenosis of the collecting vein of the DVA was also sought for. Brain abnormalities within the drainage territory of a DVA were encountered in 65.4% of the cases. Locoregional brain atrophy occurred in 29.7% of the cases, followed by white matter lesions in 28.3% of MRI investigations and 19.3% of CT investigations, CVMs in 13.3% of MRI investigations and dystrophic calcification in 9.6% of CT investigations. An intracranial haemorrhage possibly related to a DVA occurred in 2.4% cases, and a stenosis on the collecting vein was documented in 13.1% of cases. Parenchymal abnormalities were identified for all DVA sizes. Brain parenchymal abnormalities were associated with DVAs in close to two thirds of the cases evaluated. These abnormalities are thought to occur secondarily, likely during post-natal life, as a result of chronic venous hypertension. Outflow obstruction, progressive thickening of the walls of the DVA and their morphological organization into a venous convergence zone are thought to contribute to the development of venous hypertension in DVA.

Can monovoxel magnetic resonance spectroscopy (MRS) reliably follow tumour progression in low-grade glioma?21 patients with low-grade glioma underwent at least 3 MRS.For progression from a grade II to grade III tumour, a sensitivity of 57.1% and specificity of 60% were observed, with a positive predictive value (PPV) of 48.8% and a negative predictive value (NPV) of 54.5%. For progression under treatment, we obtained a sensitivity of 57.1% by N-acetylaspartate (NAA)/choline (Cho) and myoinositol/creatine (Cr) and a specificity of 100% by Cho/Cr and lipids, with a PPV of 80% and a NPV of 63.6%.We found that NAA/Cho is the best marker of tumour progression before therapy, with a sensitivity of 53.9%. For the therapeutic response, sensitivity was only 28.2%.

Summary: Purpose: Clinically silent lesions localized in the splenium of the corpus callosum (SCC) are a rare finding in the magnetic resonance imaging (MRI) of patients receiving antiepileptic drugs (AEDs). They are usually of benign character but may induce unnecessary complementary examinations if their nature is unrecognized. So far, 22 cases have been described in the literature, for which different etiologies have been proposed. We describe two further cases and discuss the probable lesion etiology. Methods: We report two cases including a 25-year-old male patient and a 12-year-old female patient with a transient SCC lesion discovered in the context of a presurgical epilepsy evaluation. Results: Comprehensive MRIs, including diffusion tensor imaging–based fiber tracking of the lesion, revealed a cytotoxic edema not disrupting neuronal fibers. Serum arginine vasopressin (AVP) measurements revealed an altered secretion during the acute phase in one patient. Conclusions: On the basis of our results, we hypothesize that the lesion consists of a cytotoxic edema, possibly induced by abrupt AED concentration changes and associated to alterations of AVP secretion.

OBJECTIVE. MDCT angiography allows fast imaging of the cerebral vessels, and its potential as a noninvasive technique to detect vascular abnormalities on the basis of morphologic changes is well established. We analyzed vascular enhancement patterns of cerebral venous structures on MDCT angiography, which enabled us to diagnose dural arteriovenous fistula.CONCLUSION. MDCT angiography performed during an early arterial phase showed asymmetrically higher contrast intensity in the transverse or sigmoid sinus, or both, in five patients. In all patients, digital subtraction angiography confirmed the presence of a dural arteriovenous fistula on the side on which the higher contrast intensity appeared. Radiologists should actively look for this sign in the imaging workup of patients presenting with nonspecific symptoms that might be related to a dural arteriovenous fistula.

Velo-cardio-facial syndrome (VCFS), also known as 22q11.2 deletion syndrome, is a common genetic condition associated with increased risk for developing schizophrenia. Given that cortical malformations play an integral role in the pattern of neuroanatomical alterations associated with VCFS, the aim of the present study was to quantify and localize gyral abnormalities. Magnetic resonance images were obtained on a 1.5 T scanner. The gyrification index (GI), a measure of the degree of cortical complexity, was differentially calculated for each lobe using a semi-automated protocol. The GI was calculated for 37 patients affected by VCFS as well as for 36 comparison individuals group-matched for age, handedness, and gender. The subjects affected by VCFS showed a significant decrease in the GI in the frontal and parietal lobes compared with the control group. The pattern of decreased gyrification in the frontal and parietal lobes further defines the structural changes associated with the syndrome and suggests underlying abnormalities in neural connectivity. Aberrant connectivity may be partially responsible for the cognitive and behavioral impairments in the syndrome, as well as the high incidence of schizophrenia among affected individuals.

Summary: Purpose: The exact anatomic and neurophysiologic correlates of idiopathic generalized epilepsy (IGE) in humans are still not well understood, although the thalamus has frequently been invoked as the crucial structure in the generation of primary generalized seizures. The few in vivo magnetic resonance (MR)-based studies in IGE patients suggest an altered cortical/subcortical gray matter ratio, but with no evidence of structural alterations of the thalamus. In this study, we sought to determine the volumes of the other subcortical structures. Methods: The volumes of the caudate nucleus, putamen, pallidum as well as the thalamus were each determined in both hemispheres in 11 patients with various IGE syndromes, normalized for whole-brain volumes and then compared with 15 age-matched controls. Results: No differences were noted in thalamic volumes, confirming previous reports. However, smaller subcortical volumes were noted in the IGE patients (p < 0.009), mainly due to smaller putamen bilaterally (p ≤ 0.015). Conclusions: It is speculated that the presence of discrete frontal dysfunction, as noted in neuropsychological studies in IGE patients, indirectly supports our results because the putamen projects predominantly to the frontal cortex. Larger studies with more homogeneous patient populations are needed to determine the robustness of these findings and whether they are specific for particular IGE syndromes. Ke yW ords: MRI—Idiopathic generalized epilepsy—Volumetry—Human—Caudate nucleus— Thalamus—Pallidum—Putamen—Striatum—Basal ganglia.

Behcet disease is a chronic relapsing inflammatory condition, predominantly affecting young adults, characterised by recurrent bipolar aphtae and systemic manifestations for which tumour necrosis factor (TNF) alpha blockade has recently emerged as an effective treatment. We report the case of a patient presenting with mucocutaneous and ocular manifestations who in the course of his disease developed CNS parenchymal involvement. While being treated with pulsed cyclophosphamide and corticosteroids, he suffered a relapse of his CNS involvement that was efficaciously controlled by infliximab. No disease activity was observed during a full year of TNF blockade, associated with azathioprine, colchicine, and corticosteroids. However, 7 months after the last administration of infliximab and still under immunosuppressant agents, CNS lesions recurred. Infliximab was successfully reintroduced and since continued with no side effects. The sequence of events observed in this patient suggests that TNF blockade is efficacious in suppressing neuro-Behcet disease and once introduced should be maintained for a prolonged period of time.

CASE OF THE MONTH: ABSTRACT FEBRUARY 2004 COM. A 44-year old man presented with a 2-year history of epistaxis and a nodular lesion in the nasopharyngeal mucosa. Neuroimaging revealed a midline nasopharyngeal tumor extending through the skull base to the clivus. Following surgical resection, histological studies showed a paraganglioma, a tumor with a typical nesting pattern, abundant capillary network, and strong immunoreactivity for neuroendocrine markers. Paragangliomas of the head and neck are rare tumors, which may come to the neuropathologist's attention because of their propensity for intracranial spread. In particular, paragangliomas located in the nasopharynx may generate diagnostic difficulties, as they appear to have no connection with major paraganglia in the region. Morphologic criteria do not allow distinguishing between benign and malignant forms.

Neuroimaging technologies have improved neurology and neurosurgery by providing tools to look inside the brain and investigate its functions and diseases. As for any tool, the users should know the basics of each technique and be aware about their uses and limitations. Here we review these new techniques and illustrate their use with examples from studies at the University Hospital in Geneva. From all the techniques, MRI (Magnetic Resonance Imagery) has the highest spatial resolution. Taking advantage of the magnetic properties of the hydrogen nucleus, it is possible to reach a sub-millimeter resolution in 3D. When MRI images are digitized, they can be treated to perform re-slicing, segmentation and 3D reconstruction of cortical surfaces, as well as to measure anatomical structures (volumetry). Functional MRI (fMRI) is based on blood oxygenation changes when a task is performed or when epileptic activity occurred. Then it can be used to non-invasively show for example language, motor or epileptic network activation. Electromagnetic imaging techniques, based on EEG and MEG, have the power to localize in 3D the electrical activity of the brain with millisecond temporal resolution and then to follow the temporal activation of neuronal networks. These techniques use mathematical models and algorithms to compute 3D tomography from 2D recordings on the scalp. In the case of epilepsy, EEG allows epileptic foci identification among propagation sites when it is recorded with a sufficient number of electrodes (100) and when realistic head models are used. The functional imaging techniques from nuclear medicine (PET and SPECT) have become very useful in neuroscience to explore cerebral changes associated with neuronal pathologies as well as cognitive and sensory tasks. Many efforts have been made to develop new cameras and models to increase the range of research and clinical applications. Co-registration of structural and functional images allows us to add functional information to a structural deficit, or conversely to better interpret functional images such as PET, SPECT and EEG in terms of specific anatomy. In the case of SPECT and fMRI, substraction between ictal and interictal exams points out areas involved in epileptic processes.

Background: Evidence from previous volumetric magnetic resonance studies has revealed that patients with chronic temporal lobe epilepsy show atrophy of distinct subcortical nuclei, predominantly ipsilateral to the focus side. We were interested to find out if there is also selective subcortical atrophy in patients suffering from long standing extratemporal lobe epilepsy. Methods: Thirty one patients in whom pre-surgical evaluation unambiguously localised an extratemporal focus were included in this study. Using high resolution magnetic resonance imaging, the volumes of the caudate nuclei, putamen, pallidum, and thalamus were measured bilaterally in both hemispheres and compared with measurements obtained in 15 healthy volunteers. Results: No significant difference in volumes was found between the two subject groups, or in any subgroup of extratemporal lobe epilepsy patients, nor was there any relation to clinical variables such as age of onset, overall seizure frequency, or disease duration. However, patients who had no or only rare generalised tonic–clonic seizures seemed to differ from the other patients and controls in that they had smaller putamen volumes bilaterally (p

Normal aging, leukoaraiosis (LA) and vascular disease particularly involve the human frontal lobes. We decided to investigate a population of elderly patients referred for neuroimaging because of progressive minor cognitive deficits but no dementia. They underwent conventional Magnetic resonance imaging (MRI) using axial T1 and T2-weighted imaging as well as coronal FLAIR sequences in addition to the axial diffusion-weighted MRI. MRI allowed us to differentiate patients with leukoaraïosis (LA+) from those without it (LA-) and mapping of the apparent diffusion coefficient (ADC) to investigate local tissular water motion. We observed an increase in the ADC in all investigated patients with increasing age (r=0.326, p=0.002). This increase was observed in both patients groups (LA+ and LA-). In addition, the LA+ group had significant higher ADC values than the LA- group after controlling for age (p