Clinical practice of language fMRI in epilepsy centers: a European survey and conclusions by the ESNR Epilepsy Working Group.

PURPOSE: To assess current clinical practices throughout Europe with respect to acquisition, implementation, evaluation, and interpretation of language functional MRI (fMRI) in epilepsy patients. METHODS: An online survey was emailed to all European Society of Neuroradiology members (n = 1662), known associates (n = 6400), and 64 members of European Epilepsy network. The questionnaire featured 40 individual items on demographic data, clinical practice and indications, fMRI paradigms, radiological workflow, data post-processing protocol, and reporting. RESULTS: A total of 49 non-duplicate entries from European centers were received from 20 countries. Of these, 73.5% were board-certified neuroradiologists and 69.4% had an in-house epilepsy surgery program. Seventy-one percent of centers performed fewer than five scans per month for epilepsy. The most frequently used paradigms were phonemic verbal fluency (47.7%) and auditory comprehension (55.6%), but variants of 13 paradigms were described. Most centers assessed the fMRI task performance (75.5%), ensured cognitive-task adjustment (77.6%), trained the patient before scanning (85.7%), and assessed handedness (77.6%), but only 28.6% had special paradigms for patients with cognitive impairments. fMRI was post-processed mainly by neuroradiologists (42.1%), using open-source software (55.0%). Reporting was done primarily by neuroradiologists (74.2%). Interpretation was done mainly by visual inspection (65.3%). Most specialists (81.6%) were able to determine the hemisphere dominance for language in more than 75% of exams, attributing failure to the patient not performing the task correctly. CONCLUSION: This survey shows that language fMRI is firmly embedded in the preoperative management of epilepsy patients. The wide variety of paradigms and the use of non-CE-marked software underline the need for establishing reference standards.

How to interpret images in epileptic seizures: correlation between clinical and functional MRI findings. / Crisis epiléptica: ¿cómo interpretar la imagen? Correlación clínica-funcional.

Neuroimaging studies are essential in patients with epilepsy, both for diagnosis and surgical management. This article focuses on adult epileptic patients, reviewing the updated clinical criteria published by the International League Against Epilepsy for the definitions of seizures, epilepsy, and status epilepticus. It also describes the different types of epilepsy, the different presentations, the signs, the radiologic approach to managing seizures, and the differences between generalized and focal seizures. Finally, it discusses the relations between possible functional cerebral deficits secondary to potentially epileptogenic lesions and epilepsy surgery, underlining the importance of functional magnetic resonance imaging studies.

Glioma imaging in Europe: A survey of 220 centres and recommendations for best clinical practice.

OBJECTIVES: At a European Society of Neuroradiology (ESNR) Annual Meeting 2015 workshop, commonalities in practice, current controversies and technical hurdles in glioma MRI were discussed. We aimed to formulate guidance on MRI of glioma and determine its feasibility, by seeking information on glioma imaging practices from the European Neuroradiology community. METHODS: Invitations to a structured survey were emailed to ESNR members (n=1,662) and associates (n=6,400), European national radiologists' societies and distributed via social media. RESULTS: Responses were received from 220 institutions (59% academic). Conventional imaging protocols generally include T2w, T2-FLAIR, DWI, and pre- and post-contrast T1w. Perfusion MRI is used widely (85.5%), while spectroscopy seems reserved for specific indications. Reasons for omitting advanced imaging modalities include lack of facility/software, time constraints and no requests. Early postoperative MRI is routinely carried out by 74% within 24-72 h, but only 17% report a percent measure of resection. For follow-up, most sites (60%) issue qualitative reports, while 27% report an assessment according to the RANO criteria. A minority of sites use a reporting template (23%). CONCLUSION: Clinical best practice recommendations for glioma imaging assessment are proposed and the current role of advanced MRI modalities in routine use is addressed. KEY POINTS: • We recommend the EORTC-NBTS protocol as the clinical standard glioma protocol. • Perfusion MRI is recommended for diagnosis and follow-up of glioma. • Use of advanced imaging could be promoted with increased education activities. • Most response assessment is currently performed qualitatively. • Reporting templates are not widely used, and could facilitate standardisation.

PET/MRI and PET/MRI/SISCOM coregistration in the presurgical evaluation of refractory focal epilepsy.

We aimed to investigate the usefulness of coregistration of positron emission tomography (PET) and magnetic resonance imaging (MRI) findings (PET/MRI) and of coregistration of PET/MRI with subtraction ictal single-photon emission computed tomography (SPECT) coregistered to MRI (SISCOM) (PET/MRI/SISCOM) in localizing the potential epileptogenic zone in patients with drug-resistant epilepsy. We prospectively included 35 consecutive patients with refractory focal epilepsy whose presurgical evaluation included a PET study. Separately acquired PET and structural MRI images were coregistered for each patient. When possible, ictal SPECT and SISCOM were obtained and coregistered with PET/MRI. The potential location of the epileptogenic zone determined by neuroimaging was compared with the seizure onset zone determined by long-term video-EEG monitoring and with invasive EEG studies in patients who were implanted. Structural MRI showed no lesions in 15 patients. In these patients, PET/MRI coregistration showed a hypometabolic area in 12 (80%) patients that was concordant with seizure onset zone on EEG in 9. In 7 patients without MRI lesions, PET/MRI detected a hypometabolism that was undetected on PET alone. SISCOM, obtained in 25 patients, showed an area of hyperperfusion concordant with the seizure onset zone on EEG in 7 (58%) of the 12 of these patients who had normal MRI findings. SISCOM hyperperfusion was less extensive than PET hypometabolism. A total of 19 patients underwent surgery; 11 of these underwent invasive-EEG monitoring and the seizure onset zone was concordant with PET/MRI in all cases. PET/MRI/SISCOM coregistration, performed in 4 of these patients, was concordant in 3 (75%). After epilepsy surgery, 13 (68%) patients are seizure-free after a mean follow-up of 4.5 years. PET/MRI and PET/MRI/SISCOM coregistration are useful for determining the potential epileptogenic zone and thus for planning invasive EEG studies and surgery more precisely, especially in patients without lesions on MRI.

[Successful functional hemispherectomy in adult patients with refractory epilepsy]. / La hemisferectomía funcional también es eficaz en pacientes adultos con epilepsia catastrófica.

INTRODUCTION: Functional hemispherectomy is a surgical technique used to treat refractory epilepsies in the setting of extensive unilateral hemispheric lesions. Most series of hemispherectomies include mainly pediatric patients. METHODS: We report our series of four adult patients that have undergone functional hemispherectomy for their refractory epilepsy. Each one had a complete presurgical evaluation including video EEG, neuropsychological testing and anatomical and functional neuroimaging. In three of them, the epilepsy was secondary to a middle cerebral artery infarction. One patient had Rasmussen encephalitis. RESULTS: After surgery, three patents have become completely seizure free (follow up 13-26 months). The fourth patient has had more than 75% reduction in seizure frequency. All of them have had significant improvement in their quality of life. Early complications included an isolated tonic-clonic generalized seizure (one patient), and status epilepticus in another patients related to infection and use of meropenem. Only one patient has presented hemianopia as a permanent neurological deficit after surgery. CONCLUSIONS: Functional hemispherectomy is a good surgical option in the setting of large unilateral hemispheric lesions causing hemiparesis and intractable seizures, even in adult patients.

[The utility of interictal SPECT in temporal lobe epilepsy]. / ¿Es útil la SPECT interictal en la epilepsia del lóbulo temporal?

INTRODUCTION: Interictal brain single photon emission computed tomography (SPECT) is used in the presurgical evaluation of patients with complex partial epilepsy. The aim of the present study was to compare interictal SPECT, MRI and video-electroencephalography (EEG) for seizure focus localization in patients with temporal lobe epilepsy, one year after temporal lobectomy, in order to determine the utility of interictal brain SPECT. PATIENTS AND METHODS: Thirty four consecutive patients with refractory temporal epilepsy were evaluated with video-EEG, MRI and interictal SPECT for seizure focus localization before surgery. Seizure focus was confirmed with the clinical follow-up one year after temporal lobectomy in all patients. MRI and SPECT analysis was performed visually. RESULTS: 31/34 patients were seizure free one year after surgery and the remaining 3 patients remain with seizures occasionally. Video-EEG results coincided with postsurgical seizure focus localization in 31 (91%) patients. MRI localized seizure focus correctly in 30 (88%) patients and was normal in 3 cases. Interictal brain SPECT was normal in 10 patients and showed temporal hypoperfusion consistent with postsurgical seizure focus in 23 (68%) patients. In all patients with abnormalities in the interictal SPECT, seizure focus was identified with video-EEG or MRI. CONCLUSIONS: When MRI and video-EEG localize seizure focus in the same temporal lobe, interictal brain SPECT does not offer any additional information for surgical decision making.

Complex motor behaviors in temporal lobe epilepsy.

Complex motor behaviors differing from typical automatisms were found in 12 of 502 patients with temporal lobe epilepsy. Movements involved proximal limb segments (6) or body axis (6) and were often preceded by auras and followed by automatisms. Seven of 12 patients are seizure free after surgery. The other 5 patients declined surgery.

Can the Wada test evaluate mesial temporal function? A SPECT study.

OBJECTIVE: To assess the value of SPECT during intracarotid amobarbital procedure (IAP) to discriminate which patients performed the test with the hippocampus inactivated and correlate it with the risk of amnesia after anterior temporal lobectomy (ATL). METHODS: The authors studied 40 consecutive patients undergoing ATL for refractory epilepsy. SPECT was performed after IV injection of 99mTc-HMPAO during the IAP (IAP-SPECT). Interictal SPECT and IAP-SPECT were realigned to obtain the perfusion change percentage (PCP), allowing a quantitative measurement. Wechsler Memory Scale Revised (WMS-R) before and during the first year of follow-up was used to assess memory impairment after surgery. RESULTS: A decrease between 10 and 12% of the mean PCP values was observed in the frontal, parietal, and lateral temporal lobes of the injected side and in the contralateral cerebellum. However, no significant PCP changes were observed in the occipital or mesial temporal lobes. Thirty-eight passed the memory evaluation of the IAP and in 6 of those 38 patients a decline in memory was demonstrated 1 year after ATL. However, high preoperative neuropsychological score (in two patients) and IAP asymmetry scores (in other three patients) predicted postoperative memory risk in five of these six patients. Fourteen of the 38 patients (40%) had hypoperfusion of the hippocampus during the IAP-SPECT (i.e., the hippocampus was inactivated) and only 1 of these 14 patients (2.5%) developed memory impairment after temporal lobectomy. On the other hand, 5 of the 24 patients (13%) who had a functional hippocampus on IAP-SPECT developed memory impairment. CONCLUSIONS: The results suggest that the combination of SPECT, intracarotid amobarbital procedure, and neuropsychological testing predicted risk for all patients who had postoperative memory decline, indicating that risk prediction should be based on multiple factors. IAP-SPECT results demonstrated that the hippocampus is not inactivated in over 60% of patients and that the lack of accuracy of the IAP alone in predicting the risk of amnesia is probably related to an insufficient inactivation of the ipsilateral hippocampus during the test.

Hereditary subependymal heterotopia associated with mega cisterna magna: antenatal diagnosis with magnetic resonance imaging.

Bilateral nodular subependymal heterotopia has recently been identified as a hereditary disease linked to the X-chromosome. The sonographic findings are very subtle and difficult to observe during the second trimester when the germinal matrix is at its largest. Fetal magnetic resonance imaging facilitates visualization of the periventricular area. We report a case of bilateral nodular heterotopia associated with mega cisterna magna diagnosed by ultrasound and magnetic resonance imaging at 29 weeks' gestation. Magnetic resonance imaging of the brain of the mother revealed similar findings to those observed in the fetus and neonate. This case confirms the association between mega cisterna magna and bilateral periventricular nodular heterotopia and demonstrates that neuroimaging studies of the mother can contribute to the fetal diagnosis.

Nocturnal paroxysmal dystonia related to a prerolandic dysplasia.

Nocturnal paroxysmal dystonia (NPD) is a rare disorder characterized by attacks of short-lived dystonic, tonic and choreoatetoid movements occurring mainly during sleep. Although seizures are believed to arise from the frontal lobe, their localization is, however, uncertain due to the lack of ictal clinical-EEG correlations. Two patients are reported with episodes clinically compatible with NPD who also experienced occasional generalized tonic-clonic seizures in which there was a frontal (prerolandic) dysplasia detected by MRI. In one patient interictal/ictal SPECTs suggested that the seizure focus was over the area of dysplasia. Both patients support the notion that NPD is a type of epilepsy arising from the frontal lobe, possibly originating in the prerolandic region.

Cortical laminar necrosis caused by immunosuppressive therapy and chemotherapy.

We report three patients in whom neurologic symptoms and cortical laminar necrosis developed after immunosuppressive treatment (cyclosporin A and FK 506) and polychemotherapy (vincristine and methotrexate). Initial neuroradiologic studies showed cortical and white matter involvement. Follow-up studies showed cortical hyper-intense lesions on T1-weighted MR images, consistent with cortical laminar necrosis. The clinical and radiologic data indicate that a transient hypoxic-ischemic process could have been responsible for the encephalic lesions in these three patients.

The "target sign": is it a specific sign of CNS tuberculoma?

In brain lesions, the target sign has been defined as a central nidus of calcification or central enhancement surrounded by a ring of enhancement. It has been considered a pathognomonic finding of central nervous system (CNS) tuberculoma. The purpose of this report is to demonstrate that the target sign related to central enhancement is a nonspecific finding and may lead to erroneous diagnosis of CNS tuberculoma.

Magnetic resonance imaging of paraganglioma of the cauda equina.

The authors describe atypical magnetic resonance imaging (MRI) findings for pathologically proven paraganglioma of the filum terminale in a 27-year-old man. MRI showed an intradural tumour, which enhanced after administration of gadolinium and which showed evidence of cystic areas. Hemosiderin rings and vessels were not observed.

Differential diagnosis of leukokoria: radiologic-pathologic correlation.

Leukokoria is an abnormal pupillary light reflection that usually results from an intraocular abnormality and is seen most often in children. One-half of the cases of childhood leukokoria are caused by retinoblastoma, a malignant tumor of immature retinoblasts that manifests in a normal-sized eye as a calcified mass, is often partially necrotic, and grows into the vitreous and through the choroid. Retinoblastoma enhances with contrast material and, unlike most tumors, may be darker than vitreous on T2-weighted images. When leukokoria is associated with microphthalmia, persistent hyperplastic primary vitreous (PHPV) (28% of cases) or retinopathy of prematurity (ROP) (5% of cases) should be considered. PHPV is a congenital, usually unilateral lesion that appears as a dense tubular mass extending from the lens to the retina along the course of the hyaloid canal. Hemorrhage from PHPV produces a subhyaloid (or subretinal) fluid collection, often with characteristic blood-fluid levels. ROP is bilateral and usually manifests in premature infants who received supplemental oxygen therapy. Coats disease (16% of leukokoria) is a sporadic unilateral idiopathic retinal telangiectasia that produces a lipoproteinaceous subretinal exudate leading to complete retinal detachment. The globe has normal size but increased attenuation and signal intensity from hemorrhage without calcification or enhancement. Toxocaral endophthalmitis (16% of leukokoria) is a granulomatous reaction to the parasite in the vitreous and uveoretinal coat. Retinal astrocytoma (3% of leukokoria), which manifests in a normal-sized globe, is an indolent benign neoplasm commonly associated with phakomatoses (usually tuberous sclerosis).

An unusual frontal ganglioglioma: CT and MRI.

We describe a ganglioglioma with atypical radiological appearances, in an uncommon location. CT showed a nonenhancing low-density lesion without calcification. On MRI the lesion gave nonspecific low signal on T1-weighted images and high signal on T2-weighted images. The tumour was in the right frontal lobe, producing bulging and thinning of the calvarium.

Sacral pneumatocysts: CT appearance.

OBJECTIVE: CT findings of pneumatocyst of the sacrum have been evaluated. MATERIALS AND METHODS: Eight patients, six men and two women, with pneumatocysts of the sacrum were studied. Selective CT with 4 and 2 mm thickness was performed, and the intralesional attenuation coefficients were measured. RESULTS: All patients showed subchondral pneumatocysts of the sacrum with sclerotic margins related to the synovial portion of the sacroiliac joint. Intraarticular gas was found in six cases, and evidence of communication between the lesion and the joint was observed in two patients. Signs of bone degeneration were present in all cases. CONCLUSION: Pneumatocyst of the sacrum is a benign bone lesion associated with arthritic changes.