Hemispheric asymmetries in dorsal language pathway white-matter tracts: A magnetic resonance imaging tractography and functional magnetic resonance imaging study.

Introduction Previous studies have shown that the arcuate fasciculus has a leftward asymmetry in right-handers that could be correlated with the language lateralisation defined by functional magnetic resonance imaging. Nonetheless, information about the asymmetry of the other fibres that constitute the dorsal language pathway is scarce. Objectives This study investigated the asymmetry of the white-matter tracts involved in the dorsal language pathway through the diffusion tensor imaging (DTI) technique, in relation to language hemispheric dominance determined by task-dependent functional magnetic resonance imaging (fMRI). Methods We selected 11 patients (10 right-handed) who had been studied with task-dependent fMRI for language areas and DTI and who had no language impairment or structural abnormalities that could compromise magnetic resonance tractography of the fibres involved in the dorsal language pathway. Laterality indices (LI) for fMRI and for the volumes of each tract were calculated. Results In fMRI, all the right-handers had left hemispheric lateralisation, and the ambidextrous subject presented right hemispheric dominance. The arcuate fasciculus LI was strongly correlated with fMRI LI ( r = 0.739, p = 0.009), presenting the same lateralisation of fMRI in seven subjects (including the right hemispheric dominant). It was not asymmetric in three cases and had opposite lateralisation in one case. The other tracts presented predominance for rightward lateralisation, especially superior longitudinal fasciculus (SLF) II/III (nine subjects), but their LI did not correlate (directly or inversely) with fMRI LI. Conclusion The fibres that constitute the dorsal language pathway have an asymmetric distribution in the cerebral hemispheres. Only the asymmetry of the arcuate fasciculus is correlated with fMRI language lateralisation.

SUrface-PRojected FLuid-Attenuation-Inversion-Recovery Analysis: A Novel Tool for Advanced Imaging of Epilepsy.

OBJECTIVE: The objective of this pilot retrospective study is to describe the SUrface-PRojected FLuid-Attenuation-Inversion-Recovery (SUPR-FLAIR) analysis, a novel method mainly aimed at revealing cortical areas with subtle signal hyperintensity. METHODS: Images from 101 healthy controls and 10 patients suffering from drug-resistant partial epilepsy were retrospectively postprocessed. The brain surface was reconstructed from a 3-dimensional (3D) T1-weighted fast field echo (T1W-FFE) magnetic resonance imaging (MRI) scan. A turbo spin echo fluid attenuated inversion recovery axial scan was registered to the 3D T1W-FFE scan, and its intensity values were normalized. The cortical intensity signal was projected onto the brain surface, and surface-based analysis was performed, comparing each patient against the 101 controls. The localizations of the first positive lower P value cluster (PLPC) peak and the resection zone (RZ) were compared. We studied 5 patients with focal cortical dysplasia (3 of them with negative MRI) and 5 with hippocampal sclerosis. RESULTS: SUPR-FLAIR analysis localized the first PLPC peak in the RZ in all cases. Because all patients have been seizure free since surgery, it can be assumed that the epileptogenic zone (EZ) was included in the RZ. Therefore, SUPR-FLAIR analysis correctly aligned with the EZ, with 100% sensitivity. CONCLUSIONS: SUPR-FLAIR analysis is a noninvasive technique that could be helpful for the definition of the EZ, especially when MRI is negative. Its use could reduce the indications for invasive electroencephalography or could provide essential data to refine the strategy of intracerebral electrode implantation in the most challenging cases.

Pseudo-subarachnoid hemorrhage: a potential imaging pitfall associated with spontaneous intracranial hypotension.

OBJECTIVE: (1) To determine the frequency of CT mimics of subarachnoid hemorrhage (SAH) in a large cohort of subjects with spontaneous intracranial hypotension (SIH). (2) To emphasize the distinctive radiologic features of SIH. PATIENTS AND METHODS: CT scans of 95 subjects with SIH were retrieved and reviewed to search for findings of pseudo-SAH (CT mimics of SAH in the absence of blood). RESULTS: Pseudo-SAH radiologic findings (increased attenuation in the basilar cisterns, sylvian fissures, or along the tentorium) were detected on CT scans of 10 of the 95 SIH subjects. However, on MRI scans, these subjects exhibited the typical SIH abnormalities (diffuse pachymeningeal enhancement and brain sagging with obliteration of basilar cisterns). CONCLUSIONS: In the emergency room, SIH should be considered in the differential diagnosis between SAH and pseudo-SAH. Although SIH and SAH can share some radiologic features, SIH has distinctive MRI and CT findings. Their recognition should obviate the need for more invasive procedures (e.g., cerebral angiography) to definitely rule out SAH and an aneurismal source of bleeding.

Focal cortical dysplasia type IIa and IIb: MRI aspects in 118 cases proven by histopathology.

INTRODUCTION: This study aims to review the magnetic resonance imaging (MRI) aspects of a large series of patients with focal cortical dysplasia type II (FCD II) and attempt to identify distinctive features in the two histopathological subtypes IIa and IIb. METHODS: We retrospectively reviewed the MRI scans of 118 patients with histological proven FCD IIa (n = 37) or IIb (n = 81) who were surgically treated for intractable epilepsy. RESULTS: MRI was abnormal in 93 patients (79 %) and unremarkable in 25 (21 %). A dysplastic lesion was identified in 90 cases (97 %) and classified as FCD II in 83 and FCD non-II in seven cases. In three cases, the MRI diagnosis was other than FCD. There was a significant association between the presence of cortical thickening (p = 0.002) and the "transmantle sign" (p < 0.001) and a correct MRI diagnosis of FCD II. MRI positivity was more frequent in the patients with FCD IIb than in those with FCD IIa (91 % vs. 51 %), and the detection rate of FCD II was also better in the patients with type IIb (88 % vs. 32 %). The transmantle sign was significantly more frequent in the IIb subgroup (p = 0.003). CONCLUSIONS: The rates of abnormal MRI results and correct MRI diagnoses of FCD II were significantly higher in the IIb subgroup. Although other MRI stigmata may contribute to the diagnosis, the only significant correlation was between the transmantle sign and FCD IIb.

Rhinoscleroma in an immigrant from Egypt: a case report.

Rhinoscleroma is a chronic indolent granulomatous infection of the nose and the upper respiratory tract caused by Klebsiella rhinoscleromatis; this condition is endemic to many regions of the world including North Africa. We present a case of rhinoscleroma in a 51-year-old Egyptian immigrant with 1-month history of epistaxis. We would postulate that with increased travel from areas where rhinoscleroma is endemic to other non-endemic areas, diagnosis of this condition will become more common.

Insular-opercular seizures manifesting with sleep-related paroxysmal motor behaviors: a stereo-EEG study.

PURPOSE: Sleep-related complex motor seizures are a common feature of nocturnal frontal lobe epilepsy. Nevertheless, recent studies also suggest that sleep-related hypermotor seizures can originate in the insula. The present study describes the electroclinical features of eight drug-resistant epileptic patients with insular-opercular seizures manifesting with nocturnal complex motor seizures. METHODS: Patients underwent a comprehensive presurgical evaluation, which included history, interictal electroencephalography (EEG), scalp video-EEG monitoring, high-resolution magnetic resonance imaging (MRI), and intracerebral recording by stereo-EEG. KEY FINDINGS: Almost all patients reported an initial sensation consisting of viscerosensitive or somatosensory symptoms. Ictal clinical signs were represented by tonic-dystonic asymmetric posturing and/or hyperkinetic automatisms, including bimanual/bipedal activity and ballistic movements. Some patients exhibited dysarthric speech, hypersalivation, and apnea. Interictal and ictal EEG provided lateralizing information in the majority of patients. In three patients, MRI showed a focal anatomical abnormality in the insular-opercular region. Stereo-EEG ictal recordings demonstrated that the epileptic discharge involved simultaneously the insular cortex and the opercular region. Complex motor manifestations appeared when the ictal discharge showed an extrainsular spreading to frontomesial regions (cingulum, superior frontal gyrus, and supplementary motor area) and/or to internal and neocortical temporal lobe structures. Six patients received an insular-opercular cortical resection; three of them are seizure free (minimum follow-up 24 months) and in one a marked reduction in seizure frequency was obtained. Two patients have been operated on recently. Histology revealed a focal cortical dysplasia in three patients. One patient excluded from surgery died for sudden unexpected death in epilepsy during sleep. SIGNIFICANCE: Our data strengthen the concept that sleep-related complex motor attacks can originate in the insula, and provide useful electroclinical information to differentiate this localization from those with similar clinical characteristics. Furthermore, this study indicates that in these drug-resistant patients, surgical treatment represents a highly effective treatment option.

Growth of congenital malignant teratoid medulloepithelioma of the ciliary body: a case study.

The purpose of this study was to describe the growth pattern of congenital malignant teratoid medulloepithelioma of the ciliary body by reporting clinical and imaging findings with pathological correlation. An 11-month-old little girl presented with a whitish-pink iris mass in the right eye resulting from a small ciliary body mass consistent with medulloepithelioma at both clinical and computed tomography (CT) findings. At CT, the lesion showed heterogeneous attenuation, without intraocular calcifications. Eleven months later, clinical and ultrabiomicroscopy showed a clear enlargement of the mass, which invaded the pupil. At magnetic resonance imaging (MRI), the lesion showed T1-weighted hyperintensity and T2-weighted slight hypointensity when compared to the vitreous and a notch in the anterolateral aspect of the ipsilateral lens. After intravenous gadolinium administration, the lesion showed intense homogeneous enhancement, and there was leakage of gadolinium in the anterior chamber, resulting from impairment of blood-aqueous barrier. Biopsy revealed a malignant teratoid medulloepithelioma. The eye was then enucleated, and histology confirmed the diagnosis. Systemic chemotherapy and radiotherapy were not performed, since there was no extraocular extension. The 57-month clinical and MRI follow-up did not show disease relapse. This uncommon case displays the natural history of congenital malignant teratoid medulloepithelioma of the ciliary body. While the tumour might have been successfully treated by local excision at diagnosis, the delay in surgical treatment led to tumour overgrowth with consequent need for enucleation. The most important prognostic feature is extraocular extension, which carries a risk of local recurrence, eventually resulting in intracranial extension and/or lymphatic spread.

Temporal lobe epilepsy: neuropathological and clinical correlations in 243 surgically treated patients.

The present study included analysis of data from 243 patients surgically treated for Temporal Lobe Epilepsy (TLE). Resection was confined to the temporal lobe, with at least two years of follow-up, and specimens sufficiently preserved to allow a precise evaluation of both lateral neocortex and hippocampus. The frequency of different types of lesion and hippocampal sclerosis (HS), isolated or associated with neocortical lesions, risk factors and surgical outcomes in relation to neuropathological findings were evaluated. We found tumours in 33% of patients, malformations of cortical development (MCD) in 45%, isolated HS in 14%, no lesion in 5% and less common lesions in 3%. HS was present in 8% of tumour cases and 70% of MCD. Statistical analysis of antecedents was significantly associated only with febrile seizures (FS). In MCD patients with no history of FS, a strong association between HS and duration of epilepsy was revealed. A Class I outcome was identified in 87% of cases with tumours and 79% in cases with MCD. In 93 patients the antiepileptic drug therapy was withdrawn. Our findings show that MCD, which is significantly associated with HS, is the most common lesion in TLE and support the concept that an optimal outcome is obtained when mesial and neocortical structures are removed. FS are particularly relevant in patients with focal cortical dysplasia and HS.

Coma resulting from spontaneous intracranial hypotension treated with the epidural blood patch in the Trendelenburg position pre-medicated with acetazolamide.

A 62-year-old man had a new onset of severe, orthostatic headache which eventually progressed to a stupor and a coma 3 weeks later. A computed tomography (CT) scan showed bilateral chronic subdural haematoma and magnetic resonance imaging (MRI) of the brain showed the typical findings of spontaneous intracranial hypotension (SIH). After pre-medication with acetazolamide, he was treated with three lumbar autologous epidural blood patches (EBPs) and kept in the Trendelenburg position, with full recovery. The first lumbar autologous EBP was ineffective and the second was only partially effective because of incorrect execution of the procedure as shown by spinal neuroimaging examination post-EBP. A spinal neuroimaging examination post-EBP is therefore to be recommended in order to confirm the correct execution of procedure. Pre-medication with acetazolamide and keeping the patient in the Trendelenburg position could reduce the flow of spinal cerebrospinal (CSF) leak favouring sealing of the hole.

Molecular screening test in familial forms of cerebral cavernous malformation: the impact of the Multiplex Ligation-dependent Probe Amplification approach.

Object The purpose of this study was to underline the effectiveness of molecular analysis in cerebral cavernous angioma, with special attention to the familial forms. Methods Multiplex Ligation-dependent Probe Amplification analysis integrates the consecutive sequence analysis of the 3 genes (Krit1/CCM1, MGC4607/CCM2, and PDCD10/CCM3) known to be responsible for cerebral cavernous malformation lesions. Results The Multiplex Ligation-dependent Probe Amplification analysis revealed a new mutation, a heterozygous exon 9/10 deletion of Krit1, in the proband and in all affected family members. Conclusions The identification of the molecular defect allows physicians to screen family members at risk and to identify affected individuals before the onset of clinical symptoms caused by the presence of lesions.

Epilepsy.

MR is a fundamental step in the diagnostic path of patients with medically refractory partial epilepsy (MRPE) potentially amenable to surgery. The most frequent lesions harboured by these patients are: malformations of cortical development (MCD), mainly focal cortical dysplasias (FCD); epileptogenic tumours, such as dysembryoplastic neuroepithelial tumours (DNT) and gangliogliomas (GG); and mesial temporal sclerosis (MTS).

Neuroimaging abnormalities in adult medulloblastoma undergoing intensified therapy.

We report on radiological abnormalities resembling recurrent tumor in adult medulloblastoma receiving intensified chemotherapy and radiotherapy. Evidence provided in this paper confirms previous reports in the pediatric population and suggests that neuroradiologist and medical oncologists should be aware of new possible radiological findings related to aggressive treatments for brain tumors.

Epilepsy surgery in children: results and predictors of outcome on seizures.

PURPOSE: To retrospectively analyze the results on seizures of surgery in children with drug-resistant focal epilepsy. To identify the factors predicting seizure control among several presurgical, surgical, and postsurgical variables. METHODS: One hundred thirteen patients (67 male, 46 female), younger than 16 years, operated on from 1996 to 2004 and followed-up for at least 2 years were identified. Individualized microsurgical resections, aimed at removal of the epileptogenic zone, were performed according to the results of tailored presurgical evaluations, which included stereo-electroencephalographic recording with intracerebral electrodes when needed. Risk of seizure recurrence was assessed for the considered variables by bivariate and multivariate analysis. RESULTS: Mean age at surgery was 8.8 years, mean duration of epilepsy was 5.7 years, and mean age at seizure onset was 3.1 years. One hundred eight patients (96%) had an abnormal magnetic resonance imaging. At postoperative follow-up (mean duration 55.1 month), 77 patients (68%) were in Engel's class I, with 68 patients (60%) being seizure free (Engel's classes Ia and Ic). At multivariate analysis, variables associated with a significantly lower risk of seizure recurrence were unifocal lesion at MRI and older age at seizure onset (presurgical variables), temporal unilobar resection and complete lesionectomy (surgical variables), diagnosis of glial-neuronal tumors (postsurgical variables). CONCLUSIONS: Surgery is a valuable option for children with drug-resistant focal epilepsies which may provide excellent results in a considerable amount of cases. Since results of surgery for epilepsy strongly depend on the presurgical identification of the Epileptogenic Zone, future work should be focused on refinement and implementation of diagnostic strategies.

Clinical, magnetic resonance imaging, and genetic study of 5 Italian families with cerebral cavernous malformation.

BACKGROUND: Cerebral cavernous malformations (CCMs) are congenital vascular anomalies of the central nervous system that can result in seizures, hemorrhage, recurrent headaches, and focal neurologic deficits. These CCMs can occur as sporadic or autosomal dominant conditions, although with incomplete penetrance and variable clinical expression. Three CCM loci have been identified, on chromosomes 7q21-22 (CCM1; Online Mendelian Inheritance in Man [OMIM] 116860), 7p13-15 (CCM2; OMIM 603284), and 3q25.2-27 (CCM3; OMIM 603285), and 3 genes have been cloned, KRIT1 on CCM1, MGC4607 on CCM2, and PDCD10 on CCM3. Mutations in KRIT1 account for more than 40% of CCMs. OBJECTIVE: To describe the results of a comprehensive evaluation of 5 Italian families affected with CCM. DESIGN: Clinical, magnetic resonance imaging, and KRIT1 gene analysis. SETTING: University academic teaching hospitals. PATIENTS: Fifteen patients with CCM diagnosed according to defined criteria and 45 at-risk, symptom-free relatives. RESULTS: Three novel and 2 described mutations were found in KRIT1. The families included 33 KRIT1 mutation carriers, 57.6% of whom had no symptoms. Magnetic resonance imaging revealed CCM lesions in 82.3% of symptom-free mutation carriers. CONCLUSIONS: The data confirm both incomplete clinical and neuroimaging penetrance in families with the KRIT1 mutation. This consideration is important in genetic counseling. Moreover, the data emphasize both the importance of magnetic resonance imaging in the diagnosis of CCM and the potential for DNA-based diagnosis to identify subjects at risk.

Seizure outcome after resection of cavernous malformations is better when surrounding hemosiderin-stained brain also is removed.

PURPOSE: Considering the epileptogenic effect of cavernoma-surrounding hemosiderin, assumptions are made that resection only of the cavernoma itself may not be sufficient as treatment of symptomatic epilepsy in patients with cavernous malformations. The purpose of this study was to test the hypothesis whether seizure outcome after removal of cavernous malformations may be related to the extent of resection of surrounding hemosiderin-stained brain tissue. METHODS: In this retrospective study, 31 consecutive patients with pharmacotherapy-refractory epilepsy due to a cavernous malformation were included. In all patients, cavernomas were resected, and all patients underwent pre- and postoperative magnetic resonance imaging (MRI). We grouped patients according to MRI findings (hemosiderin completely removed versus not/partially removed) and compared seizure outcome (as assessed by the Engel Outcome Classification score) between the two groups. RESULTS: Three years after resection of cavernomas, patients in whom hemosiderin-stained brain tissue had been removed completely had a better chance for a favorable long-term seizure outcome compared with those with detectable postoperative hemosiderin (p=0.037). CONCLUSIONS: Our study suggests that complete removal of cavernoma-surrounding hemosiderin-stained brain tissue may improve epileptic outcome after resection of cavernous malformations.

Stereoelectroencephalography in the presurgical evaluation of focal epilepsy: a retrospective analysis of 215 procedures.

OBJECTIVE: To report on indications, surgical technique, results, and morbidity of stereoelectroencephalography (SEEG) in the presurgical evaluation of patients with drug-resistant focal epilepsy. METHODS: Two-hundred fifteen stereotactic implantations of multilead intracerebral electrodes were performed in 211 patients (4 patients were explored twice), who showed variable patterns of localizing incoherence among electrical (interictal/ictal scalp electroencephalography), clinical (ictal semeiology), and anatomic (magnetic resonance imaging [MRI]) investigations. MRI scanning showed a lesion in 134 patients (63%; associated with mesial temporal sclerosis in 7) and no lesion in 77 patients (37%; with mesial temporal sclerosis in 14 patients). A total of 2666 electrodes (mean, 12.4 per patient) were implanted (unilaterally in 175 procedures and bilaterally in 40). For electrode targeting, stereotactic stereoscopic cerebral angiograms were used in all patients, coupled with a coregistered three-dimensional MRI scan in 108 patients. RESULTS: One hundred eighty-three patients (87%) were scheduled for resective surgery after SEEG recording, and 174 have undergone surgery thus far. Resections sites were temporal in 47 patients (27%), frontal in 55 patients (31.6%), parietal in 14 patients (8%), occipital in one patient (0.6%), rolandic in one patient (0.6%), and multilobar in 56 patients (32.2%). Outcome on seizures (Engel's classification) in 165 patients with a follow-up period of more than 12 months was: Class I, 56.4%; Class II, 15.1%; Class III, 10.9%; and Class IV, 17.6%. Outcome was significantly associated with the results of MRI scanning (P = 0.0001) and with completeness of lesion removal (P = 0.038). Morbidity related to electrode implantation occurred in 12 procedures (5.6%), with severe permanent deficits from intracerebral hemorrhage in 2 (1%) patients. CONCLUSION: SEEG is a useful and relatively safe tool in the evaluation of surgical candidates when noninvasive investigations fail to localize the epileptogenic zone. SEEG-based resective surgery may provide excellent results in particularly complex drug-resistant epilepsies.

Neuroimaging of focal cortical dysplasia: neuropathological correlations.

Focal cortical dysplasia is a well-known cause of intractable epilepsy with early onset of seizures, and is potentially amenable to surgical therapy. It was first described by Taylor in 1971 as a peculiar malformative disorganisation of the neocortex characterised at histology by loss of cortical lamination and accompanied by giant, dysmorphic neurones and, most frequently, by "balloon cells" littered throughout the cortex and sub-cortical white matter. While in the past decades the term "cortical dysplasia" has referred to various malformations of cortical development, such as agyria, pachygyria, polymicrogyria, heterotopia and hemimegalencephaly, it is now widely accepted that the entity identified by Taylor should be considered separately, from both histological and neuroimaging standpoints. More recently, the recognition of various histological subtypes of focal cortical dysplasia characterised by different degrees of cortical disruption with or without cytological abnormalities has generated several classifications that are still unsatisfactory. With better magnetic resonance capability, subtle and very small focal cortical dysplasias may now be visualised and the differential magnetic resonance aspects of the histological subgroups can be established. We will discuss the problem of histopathological classification and magnetic resonance imaging differentiation of the various subtypes of focal cortical dysplasia in the light of personal data collected from a large series of epileptic patients who underwent surgery and had a histological diagnosis of focal cortical dysplasia.