Search

Electrical source imaging is used in presurgical epilepsy evaluation and in cognitive neurosciences to localize neuronal sources of brain potentials recorded on EEG. This study evaluates the spatial accuracy of electrical source imaging for known sources, using electrical stimulation potentials recorded on simultaneous stereo-EEG and 37-electrode scalp EEG, and identifies factors determining the localization error. In 11 patients undergoing simultaneous stereo-EEG and 37-electrode scalp EEG recordings, sequential series of 99–110 biphasic pulses (2 ms pulse width) were applied by bipolar electrical stimulation on adjacent contacts of implanted stereo-EEG electrodes. The scalp EEG correlates of stimulation potentials were recorded with a sampling rate of 30 kHz. Electrical source imaging of averaged stimulation potentials was calculated utilizing a dipole source model of peak stimulation potentials based on individual four-compartment finite element method head models with various skull conductivities (range from 0.0413 to 0.001 S/m). Fitted dipoles with a goodness of fit of ≥80% were included in the analysis. The localization error was calculated using the Euclidean distance between the estimated dipoles and the centre point of adjacent stimulating contacts. A total of 3619 stimulation locations, respectively, dipole localizations, were included in the evaluation. Mean localization errors ranged from 10.3 to 26 mm, depending on source depth and selected skull conductivity. The mean localization error increased with an increase in source depth (r(3617) = [0.19], P = 0.000) and decreased with an increase in skull conductivity (r(3617) = [−0.26], P = 0.000). High skull conductivities (0.0413–0.0118 S/m) yielded significantly lower localization errors for all source depths. For superficial sources (40 mm, high skull conductivities of 0.0413 and 0.0206 S/m yielded significantly lower localization errors. In relation to stimulation locations, the majority of estimated dipoles moved outward-forward-downward to inward-forward-downward with a decrease in source depth and an increase in skull conductivity. Multivariate analysis revealed that an increase in source depth, number of skull holes and white matter volume, while a decrease in skull conductivity independently led to higher localization error. This evaluation of electrical source imaging accuracy using artificial patterns with a high signal-to-noise ratio supports its application in presurgical epilepsy evaluation and cognitive neurosciences. In our artificial potential model, optimizing the selected skull conductivity minimized the localization error. Future studies should examine if this accounts for true neural signals.

ObjectiveTo determine whether a fraction of patients with primary CNS lymphoma (PCNSL) had been cured by systemic and intraventricular methotrexate- and cytarabine-based chemotherapy (Bonn protocol) after a very long-term follow-up of nearly 20 years.MethodsSixty-five patients (median age 62 years, range 27–75; median Karnofsky performance score 70, range 20–90) had been treated with systemic and intraventricular polychemotherapy without whole brain radiotherapy from September 1995 until December 2001. All patients still alive in 2019 were contacted and interviewed on their current life situation.ResultsMedian follow-up for surviving patients was 19.6 years (17.5–23.3 years). Out of 65 patients, 11 (17%) were still alive. Six of those never experienced any relapse. For the whole study population, median overall survival (OS) was 4.4 years (95% confidence interval [CI] 2.9–5.9); for patients ≤60 years, 11.0 years (95% CI 4.8–17.0). The 10-year OS rate for the entire cohort was 29% and the estimated 20-year OS rate was 19%. Four late relapses were observed after 9.8, 10.3, 13.3, and 21.0 years.ConclusionAt a median follow-up of 19.6 years, 17% of patients were alive and free of tumor; however, even after response for decades, an inherent risk of relapse, either systemic or cerebral, characterizes the biology of PCNSL.Classification of evidenceThis work provides Class III evidence that PCNSL treatment with methotrexate-based polychemotherapy including intraventricular therapy is associated with long-term disease control in some patients.

Background To prospectively analyze factors associated with detecting epileptogenic lesions on MRI within the work-sharing process of neurologists, epileptologists, radiologists and neuroradiologists. Methods We assembled four sets of six MRI scans, each set representing five typical epileptogenic lesions (hippocampal sclerosis or limbic encephalitis; focal cortical dysplasias; periventricular nodular or other heterotopias; long-term epilepsy associated tumors; gliotic scar, hemosiderin or cavernoma), and non - lesional epilepsy. At professional conferences, we invited neurologists, epileptologists, radiologists, and neuroradiologists to read two out of four MRI sets, one of which was presented with a clinical focus hypothesis. Participants were randomly assigned to MRI sets. Effects of examiners’ specialty, duration of training and professional experience on detection rate of epileptogenic lesions were investigated. Results Fourty-eight neurologists, 22 epileptologists, 20 radiologists and 21 neuroradiologists read 1323 MRI scans. Overall, 613 of 1101 (55.7%) epileptogenic lesions were detected. Long-term epilepsy associated tumors (182/221, 82.4%) were found more frequently than gliotic scar, hemosiderin or cavernoma (157/220, 71.4%), hippocampal sclerosis or limbic encephalitis (141/220, 64.1%), nodular heterotopia (68/220, 30.9%) and focal cortical dysplasias (65/220, 29.5%, p p = 0.037). Neuroradiologists and epileptologists were more likely than radiologists and neurologists to be amongst the most successful readers. In multivariable analysis, type of epileptogenic lesion, specialty of MRI reader, and provision of focus hypothesis predicted correct identification of epileptogenic lesions. Conclusions Epileptogenic lesions are often not recognized on MRI even by expert readers. Their detection can be improved by providing a focus hypothesis. These results stress the need for training in the MRI characteristics of epilepsy - specific pathology, and, most importantly, interdisciplinary communication between neurologists/epileptologists and (neuro)radiologists to improve detection of epileptogenic lesions.

PurposeTo retrospectively evaluate the safety and efficacy of the endovascular treatment of wide-necked intracranial aneurysms assisted by a novel intra-/extra-aneurysm stent-like implant (pCONus).MethodsInitial and follow-up angiographic and clinical results are presented of 25 patients with 25 unruptured and ruptured wide-necked intracranial aneurysms treated by reconstruction of the aneurysm neck using the pCONus implant followed by coil occlusion of the fundus.ResultsSuccessful intra-/extra-aneurysm deployment of the pCONus with coil occlusion of the fundus was achieved in all but one case. Procedure-related ischemic complications were observed in three cases with permanent deterioration in one. Acceptable aneurysm occlusion was achieved in all cases. Follow-up angiography revealed sufficient occlusion in 81.0% of the aneurysms. Intimal hyperplasia in the stented segment of the parent artery or device migration has not been observed to date.ConclusionsThe pCONus device offers a promising treatment option for complex wide-necked bifurcation intracranial aneurysms. Acute or delayed dislocations of coils into the parent artery are successfully avoided.

There is only limited data on the influence of the admission time (normal business hours versus nighttime and weekends) on procedural timings, revascularization efficacy, and outcome after mechanical thrombectomy. We investigated whether the admission time has an impact on the above-mentioned factors.Our neurointerventional database was screened for all mechanical thrombectomies in anterior circulation acute ischemic stroke between 07/13 and 06/14. Outcome measures were procedural timings and clinical and demographic data; we compared patients who were admitted at normal business hours (Monday to Friday 8:00-18:00) to those admitted at night or at the weekend.98 patients were identified. Of them, 52 (53%) were admitted during normal business hours, the remainder at night or at weekend. There was no statistically significant difference between the groups regarding the time from symptom-onset to admission, baseline National Institutes of Health Stroke Scale (NIHSS) or IVT-rate. There was a significant difference between groups for door-to-reperfusion timing, favoring patients admitted during normal business hours (146 versus 165 min, p = 0.02). Door-to-groin-puncture and groin-puncture-to-reperfusion time did not differ significantly. The rate of successful revascularizations (mTICI ≥ 2b) and the rate of favorable clinical outcome at discharge (mRS ≤ 2) did not differ between groups (77% versus 78% and 37% versus 35%, respectively).There was a statistically significant prolongation of door-to-reperfusion timings for patients admitted during nighttime and weekends; it went along neither with a lower rate of successful revascularizations nor with a lower rate of favorable outcome in our series.AFatrial fibrillationAISacute ischemic strokeCTAcomputed tomography angiographyDMdiabetes mellitusENTembolization to new territoryEVTendovascular therapyHLPhyperlipoproteinemiaHTNhypertensionIQRinter-quartile rangeIVTintravenous thrombolysismRSmodified Rankin ScaleMTmechanical thrombectomyNIHSSNational Institutes of Health Stroke Scalen.s.not significantsICHsymptomatic intracranial hemorrhage.

BACKGROUND AND PURPOSE: Several small case series reported a favorable clinical outcome for emergency stent placement in the extracranial internal carotid artery combined with mechanical thrombectomy in acute stroke. The rate of postinterventional symptomatic intracranial hemorrhages was reported to be as high as 20%. Therefore, we investigated the safety and efficacy of this technique in a large multicentric cohort. MATERIALS AND METHODS: The data bases of 4 German stroke centers were screened for all patients who received emergency stent placement of the extracranial internal carotid artery in combination with mechanical thrombectomy of the anterior circulation between 2007 and 2014. The primary outcome measure was the rate of symptomatic intracranial hemorrhage according to the European Cooperative Acute Stroke Study III criteria; secondary outcome measures included the angiographic revascularization results and clinical outcome. RESULTS: One hundred seventy patients with a median age of 64 years (range, 25–88 years) were treated. They presented after a median of 98 minutes (range, 52–160 minutes) with a median NIHSS score of 15 (range, 12–19). Symptomatic intracranial hemorrhages occurred in 15/170 (9%) patients; there was no statistically significant difference among groups pertaining to age, sex, intravenous rtPA, procedural timings, and the rate of successful recanalization. In 130/170 (77%) patients, a TICI score of ≥2b could be achieved. The in-hospital mortality rate was 19%, and 36% of patients had a favorable outcome at follow-up. CONCLUSIONS: Emergency stent placement in the extracranial internal carotid artery in combination with anterior circulation thrombectomy is effective and safe. It is not associated with a significantly higher risk of symptomatic intracranial hemorrhage compared with published series for mechanical thrombectomy alone.

Background and purpose The focus of this study was to determine ease of deployment, safety and effectiveness of the LVIS Jr device. Methods A retrospective analysis was performed of 32 cases comprising 34 aneurysms in which the LVIS Jr device was used for stent-assisted coil embolization of intracranial aneurysms from February to October 2012, including all clinical and angiographic data as well as mid-term follow-up (1–12 months of treatment). Results The median age of the patients was 54 years (range 21–76) and 19 (59%) were women. The aneurysms were ruptured in 12/34 cases (35.3%); 26 (76.4%) were located within the anterior circulation and the remaining 8 (23.5%) were located in the posterior circulation. Eleven of the 34 aneurysms (32.3%) were treated with a Y-stent configuration. Immediate total occlusion was observed in 16/34 (47%), near total occlusion (90–95%) in 5/34 (14.7%) and a ‘dog ear’ or subtotal occlusion in 12/34 (35.2%). A single aneurysm was treated without coil embolization. Complications occurred in 5/34 cases (15%), including two cases of in-stent thrombosis. Conclusions Implantation of the LVIS Jr device as a support device for stent-assisted coil embolization seems to be safe and effective. The LVIS Jr device can also be implanted in a Y-stent configuration, offering a novel technique with a potentially lower risk of thromboembolic complications compared with other devices.

Background Mechanical thrombectomy has been shown to be an effective and safe therapy for patients suffering an acute stroke. However, shortening the time span between onset of symptoms and recanalization has been partly achieved by a technical method known as aspiration thrombectomy. Our aim is to show the effectiveness of a new tool, the ACE 64, in order to further optimize neurological outcome and to minimize complications. Method Between the December 2014 and March 2015 we identified 55 Patients with acute ischemic stroke and occlusion of large cerebral vessels. These were treated with an aspiration thrombectomy using a new large bore aspiration catheter, the Penumbra ACE 64 on an intention to treat basis in multicentre setting (Utrecht, Netherlands; Murcia, Spain; St. Gallen, Switzerland; Bochum, Germany; Recklinghausen, Germany; Odense, Denmark; Homburg, Germany). Results Using the aspiration thrombectomy a Thrombolysis in Cerebral Infarction (TICI) Score of 2b or 3 was achieved in 53 of 55 cases (96,4%). In 17 cases, additional devices were used for the following reasons: Anchoring technique (9), distal vessel too small for ACE64 (5) and two cases were ACE64 could not pass preceding stenosis. In the aspiration thrombectomy only cases, a TICI score of 2b or 3 of 100% was achieved. The average time of groin puncture to revascularization was 32 min. Patients presented with a median National Institutes of Health Stroke Scale (NIHSS) score of 16 (4.0–26.0) and improved to a median NIHSS score of 4.5 (0.0–35.0) at discharge. There was each one case of major groin complication, vasospasm in preceding extracranial vessel, vessel dissection and of symptomatic intracerebral hemorrhage. Discussion Due to the design of this new large bore aspiration catheter, trackability and navigation through the carotid syphon up to M1 / M2 is excellent. This means that approaching the clot in the target vessel is fast and because of the large lumen, aspiration is effective. The complication rate is low. Most importantly, it is an extraordinarily fast method to achieving revascularization. In about 70% of patients, recanalization could be achieved by aspiration thrombectomy alone. As described with the method of aspiration thrombectomy before, there are various reasons for using additional devices. Inabout half of our cases, the stentretriever was used to maneuver the ACE64 to the thrombus. One other reason was the dislodgement of the thrombus to a distal part of the treated vessel or also called a distal embolization in the target downstream territory. In these cases, the aspiration catheter was too large to achieve a thrombectomy and a stent retriever was used. In conclusion, we are able to demonstrate the aspiration thrombectomy using the ACE64 to be an effective, easy to use, fast and safe method for treating acute stroke patients. Disclosures A. Kowoll: None. A. Moreno: None. J. Weber: None. C. Loehr: None. G. Gal: None. H. Korner: None. A. Berlis: None. W. Weber: None. T. Lo: None.

Background: Chemotherapy for primary central nervous system lymphoma (PCNSL) is based on methotrexate (MTX), which interferes with both nucleic acid synthesis and methionine metabolism. We have reported previously that genetic variants with influence on methionine metabolism are associated with MTX side effects, that is, the occurrence of white matter lesions as a sign of MTX neurotoxicity. Here, we investigated whether such variants are associated with MTX efficacy in terms of overall survival in MTX-treated PCNSL patients. Methods: We analysed seven genetic variants influencing methionine metabolism in 68 PCNSL patients treated with systemic and facultative intraventricular MTX-based polychemotherapy (Bonn protocol). Results: Median age at diagnosis was 59 years (range: 28–77), 32 patients were female. Younger age (Wald=8.9; P=0.003) and the wild-type C (CC) allele of the genotype transcobalamin c (Tc2). 776C>G (Wald=6.7; P=0.010) were associated with longer overall survival in a multivariate COX regression analysis. Conclusion: This observation suggests that the missense variant Tc2. 776C>G influences both neurotoxicity and efficacy of MTX in the Bonn PCNSL protocol.