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Background The frontal aslant tract is a deep frontal pathway connecting the superior frontal gyrus (SFG) to Broca area. This fiber is assumed to be associated with language functions, especially speech initiation and spontaneity. The aim of this study was to electrophysiologically investigate this network using corticocortical evoked potentials (CCEPs). Methods This study enrolled 8 patients with brain tumors or medically intractable focal epilepsies who underwent frontal craniotomy over the language-dominant side. All patients underwent CCEP recordings during tumor resection or during invasive evaluation for epilepsy surgery. Alternating 1-Hz electrical stimuli were delivered to pars opercularis (pO) and pars triangularis (pT), corresponding to Broca area, and SFG via the subdural grid electrodes with intensity of 10 mA. Electrocorticograms from SFG and pO/pT time-locked to 50 stimuli were averaged in each trial to obtain CCEP responses. Results In all patients, stimulation of pO/pT induced CCEP responses in SFG. CCEP responses were recorded in lateral SFG in 5 patients and in supplementary motor areas in 4 patients. Reciprocality was observed in 7 patients in the stimulation of SFG. CCEP responses were significantly faster at SFG from pO/pT than at pO/pT from SFG (Wilcoxon signed rank test, P = 0.028). Conclusions The present study demonstrated a corticocortical network connecting Broca areas and SFG in a reciprocal manner. Our findings might provide new insight into language and motor integration.

In order to preserve postoperative language function, we recently proposed a new intraoperative method to monitor the integrity of the dorsal language pathway (arcuate fasciculus; AF) using cortico-cortical evoked potentials (CCEPs). Based on further investigations (20 patients, 21 CCEP investigations), including patients who were not suitable for awake surgery (five CCEP investigations) or those without preoperative neuroimaging data (eight CCEP investigations including four with untraceable tractography due to brain edema), we attempted to clarify the clinical impact of this new intraoperative method. We monitored the integrity of AF by stimulating the anterior perisylvian language area (AL) by recording CCEPs from the posterior perisylvian language area (PL) consecutively during both general anesthesia and awake condition. After tumor resection, single-pulse electrical stimuli were also applied to the floor of the removal cavity to record subcortico-cortical evoked potentials (SCEPs) at AL and PL in 12 patients (12 SCEP investigations). We demonstrated that (1) intraoperative dorsal language network monitoring was feasible even when patients were not suitable for awake surgery or without preoperative neuroimaging studies, (2) CCEP is a dynamic marker of functional connectivity or integrity of AF, and CCEP N1 amplitude could even become larger after reduction of brain edema, (3) a 50% CCEP N1 amplitude decline might be a cut-off value to prevent permanent language dysfunction due to impairment of AF, (4) a correspondence (

Endovascular treatment of extracranial steno-occlusive lesions is an alternative to direct surgery. There is no consensus regarding the natural course and standard treatment of these lesions. The aim of this study was to identify the current status of endovascular treatment for extracranial steno-occlusive lesions. A total of 1154 procedures for extracranial steno-occlusive lesions, except for internal carotid artery stenosis, were collected from the Japanese Registry of Neuroendovascular Therapy 3 (JR-NET3). Atherosclerotic lesions were most frequent (1021 patients, 88.5%). Endovascular treatment was performed for 456 (39.5%) patients with subclavian artery, 349 (30.2%) with extracranial vertebral artery, 172 (14.9%) with the origin of common carotid artery, and 38 (3.3%) with innominate artery stenosis; the overall technical success rate was 98.0%. Percutaneous transluminal angioplasty was performed in 307 patients (26.6%) and stenting in 838 (72.6%). An embolic protection device (EPD) was used in 571 patients (49.5%), and procedure under general anesthesia was performed in 168 (14.6%). Preoperative antiplatelet therapy was administered in 1091 procedures (94.5%). A good outcome was obtained for 962 patients (83.4%). Complications were observed in 89 patients (7.7%). The procedure under general anesthesia was statistically significant factors (P

Background Herein, we report an in vivo study of a biodegradable flow diverter ( BDFD ) for aneurysm occlusion. Conceptually, BDFD s induce a temporal flow‐diverting effect and provide a vascular scaffold for neointimal formation at the neck of the aneurysm until occlusion. This offers several potential advantages, including a reduced risk of remote ischemic complications and more treatment options in case of device failure to occlude the aneurysm. Methods and Results A BDFD consisting of 48 poly‐ l ‐lactic acid wires with radiopaque markers at both ends was prepared. An in vitro degradation test of the BDFD was performed. Thirty‐six BDFD s were implanted in a rabbit aneurysm model. Digital angiography, optical coherence tomography, histopathology, and scanning electron microscopy were performed after 1, 3, and 6 months, and 1 year. The in vitro degradation test showed that the BDFD was almost degraded in 1.5 years. In the in vivo experiment, aneurysm occlusion rates were 0% at 1 month, 20% at 3 months, 50% at 6 months, and 33% at 1 year. Optical coherence tomography showed that luminal area stenosis was the highest at 3 months (16%) and decreased afterward. Immunohistochemical analysis showed that more than half of the luminal surface area was covered by endothelial cells at 1 month. Device fragmentation was not observed in any lesions. Conclusions This first in vivo study of a BDFD shows the feasibility of using BDFDs for treating aneurysms; however, a longer follow‐up is required for comprehensive evaluation of the biological and mechanical behavior peculiar to biodegradable devices.

Introduction: Although the clinical outcomes of acute ischemic strokes associated with large vessel occlusion have substantially improved by mechanical thrombectomy, the good clinical outcomes were achieved only in 40-50% of the treated patients. In the clinical practice, neuroimaging information is usually interpreted into scalar data, such as ASPECTS or lesion volume. The detection of prognostic factor might lead to the patient selection appropriate for intervention. Hypothesis: We hypothesize that more appropriate information could be directly deduced from high-dimensional neuroimaging data using deep learning algorithm. Methods: All patients with anterior circulation ischemic stroke treated with mechanical thrombectomy at our institution between December 2013 and December 2017 were included. The purpose of each model was designed to predict good clinical outcome, which was determined as modified Rankin Scale 0 to 2 at the 90-day follow-up. The “low-dimensional” model used logistic regressions with DWI-ASPECTS (ASPECTS model) or infarct volume (Lesion volume model), both features were derived from on-arrival diffusion weighted image (DWI). The “high-dimensional” model used 3D convolutional neural network (3D-CNN). The input to the 3D-CNN model was the whole DWI volume data. All models were evaluated and compared for the accuracy with 5-fold cross validation. Results and Conclusions: One hundred sixty-six patients were included for the analysis. The 3D-CNN model showed the highest accuracy 0.70±0.05 (mean±SD), compared with 0.59±0.07 of ASPECTS model and 0.53±0.05 of Lesion volume model, and was signify better than the other two models (p=0.008 with ANOVA). Although this was a preliminary analysis with limited number of patients, it is suggested that deep learning model can retrieve more valuable information from neuroimaging data than conventional low-dimensional neuroimaging factors.

Segmental arterial mediolysis(SAM)is a rare non-inflammatory and non-atherosclerotic arteriopathy associated with the occurrence of multiple aneurysms such as intracranial and intraperitoneal aneurysms. We report a case of intraperitoneal hemorrhage that occurred during the acute stage of subarachnoid hemorrhage(SAH). An 82-year-old woman presented with a sudden onset of loss of consciousness with a diagnosis of SAH. Digital subtraction angiography demonstrated two consecutive vertebral artery-posterior inferior cerebellar artery aneurysms. The larger aneurysm, which seemed to be ruptured, was successfully treated by coil embolization. On the 9th day after the onset of SAH, she developed aphasia secondary to the cerebral vasospasm. After selective intra-arterial infusion of fasudil hydrochloride, she was observed to maintain elevated systolic blood pressure. Her aphasia improved; however, on the 14th day, she suddenly developed hemorrhagic shock. An abdominal computed tomography scan demonstrated intraperitoneal hemorrhage secondary to a ruptured fusiform aneurysm of the right gastroepiploic artery. The lesion was successfully treated by coil embolization, although she became bedridden. Although a histopathological examination was not performed, her clinical, radiological, and serological presentation met the criteria of the clinical diagnosis of SAM. Elevated systolic blood pressure and excessive release of catecholamines in the acute stage of SAH might have caused the intraperitoneal hemorrhage. Non-saccular ruptured intracranial aneurysms should be considered among the differential diagnoses of SAM. In such cases, identifying and monitoring intraperitoneal aneurysms might be useful for earlier diagnosis and treatment of SAM, especially in the acute stage after SAH.

While periventricular anastomosis, a unique abnormal vasculature in moyamoya disease, has been studied in relation to intracranial hemorrhage, no study has addressed its change after bypass surgery. The authors sought to test whether direct bypass surgery could restore normal periventricular vasculature. Patients who had undergone direct bypass surgery for moyamoya disease at a single institution were eligible for the study. Baseline, postoperative, and follow-up magnetic resonance angiography (MRA) scans were scheduled before surgery, after the first surgery, and 3 to 6 months after contralateral second surgery, respectively. Sliding-thin-slab maximum-intensity-projection coronal MRA images of periventricular anastomoses were scored according to the three subtypes (lenticulostriate, thalamic, and choroidal anastomosis). Baseline and postoperative MRA images were compared to obtain a matched comparison of score changes in the surgical and nonsurgical hemispheres within individuals (intra-individual comparison). Of 110 patients, 42 were identified for intra-individual comparisons. The periventricular anastomosis score decreased significantly in the surgical hemispheres (median, 2 versus 1; p

In recent years, stereotactic electroencephalography(SEEG)has been focused on as a new invasive method for epileptic focus detection. Although the covering area of the brain surface is smaller than the invasive estimation with subdural electrodes, SEEG can evaluate foci that are deeply seated, noncontiguous leaves, and/or bilateral hemispheres. In addition, SEEG can capture consecutive changes in seizure activity in three dimensions. Due to the development of neuroimaging, computer-assisted, and robotic surgery technology, SEEG insertion began to be commonly used worldwide. Although the approximate complication rates of SEEG are estimated as 1% to 3%, which is lower than that of subdural electrode implantation, the risks of major complications, such as permanent neurological deficit and death, are equivalent. Therefore, meticulous procedure must be needed. To introduce SEEG for intractable partial epilepsy, we acquired approval from the institutional review board and concurrently imported surgical devices and electrodes from the manufacturer in the United States for two surgical candidates. We safely performed SEEG insertion, focal identification, and brain functional mapping by cortical electrical stimulation in two cases. Insertion was difficult for some electrodes, which could be due to the lack of adequate surgical device and large skull angle. Hopefully, the official installation of SEEG will be planned in the near future. We hereby reported tips and pitfalls of SEEG implantation through our own experience in a single institute.

This case report describes the usefulness of delay alternating with nutation for tailored excitation (DANTE)-prepared, contrast-enhanced magnetic resonance imaging (CE-MRI) for detecting the rupture site of an arteriovenous malformation (AVM). A ruptured intranidal aneurysm was confirmed histopathologically. Accurate non-invasive information about the possible rupture site of an AVM is critical for optimal treatment and evaluation. Vessel wall enhancement visualized by DANTE-prepared CE-MRI may be a useful tool for providing information about changes in inflammatory status and vulnerability to further developments.

Objective To evaluate infective complications with intracranial electroencephalography (EEG) recording so as to lessen them. Methods A database of intracranial monitoring cases with subdural electrodes at Kyoto University Hospital between May 1992 and March 2012 was retrospectively reviewed. Results This analysis included 46 EEG monitoring sessions. Infective complications related to intracranial electrodes occurred in 4 monitoring sessions (8.7%; 3 male patients). Causative agents were identified as Staphylococcus aureus in 3 monitoring sessions and Staphylococcus epidermidis in 1 session. In univariate analysis, the season of monitoring was identified as the sole significant risk factor. More infective complications occurred when monitoring occurred in autumn. More infective complications tended to occur in patients who had implantation in the right side or discontinuation of intravenously administered prophylactic antibiotics, although these factors were not statistically significant. Age, sex, duration of monitoring, number of electrodes, and pathologic diagnosis did not seem to be associated with an increased risk of infective complications. Infective complications had no significant influence on seizure outcome. Conclusions Invasive EEG monitoring during autumn might be a risk factor in terms of infective complications. S aureus was a common pathogen.

Laughter consists of both motor and emotional aspects. The emotional component, known as mirth, is usually associated with the motor component, namely, bilateral facial movements. Previous electrical cortical stimulation (ES) studies revealed that mirth was associated with the basal temporal cortex, inferior frontal cortex, and medial frontal cortex. Functional neuroimaging implicated a role for the left inferior frontal and bilateral temporal cortices in humor processing. However, the neural origins and pathways linking mirth with facial movements are still unclear. We hereby report two cases with temporal lobe epilepsy undergoing subdural electrode implantation in whom ES of the left basal temporal cortex elicited both mirth and laughter-related facial muscle movements. In one case with normal hippocampus, high-frequency ES consistently caused contralateral facial movement, followed by bilateral facial movements with mirth. In contrast, in another case with hippocampal sclerosis (HS), ES elicited only mirth at low intensity and short duration, and eventually laughter at higher intensity and longer duration. In both cases, the basal temporal language area (BTLA) was located within or adjacent to the cortex where ES produced mirth. In conclusion, the present direct ES study demonstrated that 1) mirth had a close relationship with language function, 2) intact mesial temporal structures were actively engaged in the beginning of facial movements associated with mirth, and 3) these emotion-related facial movements had contralateral dominance.

The preservation of language function during brain surgery still poses a challenge. No intraoperative methods have been established to monitor the language network reliably. We aimed to establish intraoperative language network monitoring by means of cortico-cortical evoked potentials (CCEPs). Subjects were six patients with tumors located close to the arcuate fasciculus (AF) in the language-dominant left hemisphere. Under general anesthesia, the anterior perisylvian language area (AL) was first defined by the CCEP connectivity patterns between the ventrolateral frontal and temporoparietal area, and also by presurgical neuroimaging findings. We then monitored the integrity of the language network by stimulating AL and by recording CCEPs from the posterior perisylvian language area (PL) consecutively during both general anesthesia and awake condition. High-frequency electrical stimulation (ES) performed during awake craniotomy confirmed language function at AL in all six patients. Despite an amplitude decline (≤32%) in two patients, CCEP monitoring successfully prevented persistent language impairment. After tumor removal, single-pulse ES was applied to the white matter tract beneath the floor of the removal cavity in five patients, in order to trace its connections into the language cortices. In three patients in whom high-frequency ES of the white matter produced naming impairment, this “eloquent” subcortical site directly connected AL and PL, judging from the latencies and distributions of cortico- and subcortico-cortical evoked potentials. In conclusion, this study provided the direct evidence that AL, PL, and AF constitute the dorsal language network. Intraoperative CCEP monitoring is clinically useful for evaluating the integrity of the language network. Hum Brain Mapp 35:4345–4361, 2014. © 2014 Wiley Periodicals, Inc.

Introduction Human brain operates with oscillatory activity in different frequency bands. For example, mu rhythm is well known as an idling rhythm observed in the central area related to motor function. We observed some rhythmic pattern in the averaged waveforms in the CCEP investigation (called “oscillatory response” here), which is originally a method to trace connectivity by single electrical pulse stimulation. We report on the frequency and distribution of the oscillatory responses in CCEP. Methods Subjects are 5 intractable epilepsy patients who underwent chronic implantation of subdural electrodes for presurgical evaluation. Written informed consents were obtained from all subjects. Single-pulse stimuli (0.3 ms, 8–10 mA, alternating polarity, 30 × 2 trials) were applied through two adjacent electrodes (52.8 ± 15.3 stimulus sites per patient). CCEP was recorded from subdural electrodes (105.2 ± 31.8 electrodes per patient) placed on the lateral and medial aspect of the cerebral hemisphere. Lateral fronto-parietal area was covered in all subjects. An oscillatory response in CCEP was detected by visual inspection on the averaged waveform according to the following criteria; (1) it has at least two pairs of peak and trough spaced equally, (2) it can be overlapped with other evoked responses (typical N1/ N2 response). If more than one rhythms with different frequencies were observed in the same electrode, we counted the largest one in amplitude. Results Totally, 2362 oscillatory responses (7.9%) were detected in 29891 observations in 5 subjects, including 443 alpha-band responses (7.5–13.5 Hz), 312 beta-band responses (13.5–30 Hz) and 1505 theta-band responses (3.5–7.5 Hz). Theta rhythm was observed predominantly in the temporal lobe including the basal temporal area (the occurrence rate was 12.45%). Alpha rhythm was observed more often in the parietal lobe including the postcentral gyrus (the occurrence rate was 4.57%), while beta rhythm was often observed around precentral gyrus (the occurrence rate was 1.98%). The frequency of the resting rhythmic activity was equal to that of oscillatory CCEP response in the alpha band in the postcentral gyrus in all subjects. This alpha activity was considered as mu rhythm in all the 3 subjects who performed a hand grasping task. Conclusion Single pulse electrical stimulation evoked oscillatory CCEP responses preferentially in the temporal lobe and the perirolandic area. The correspondence of frequency between the oscillatory response and mu rhythm implies the phase resetting of the physiological oscillation by exogenous input. This unique oscillatory CCEP may help to map these functionally important cortical regions.

Surgical intervention is expected to improve the quality of life in patients with intractable epilepsy by providing adequate seizure control. Although many previous studies showed various rates of seizure freedom, definite conclusions have not yet been made regarding outcomes. In order to clarify the long-term postoperative outcome for a period up to 10 years, a retrospective review of our patients was performed longitudinally by using the survival analysis method. The postoperative state of epilepsy in 76 patients who underwent resection surgery was assessed based on Engel’s criteria. In addition, Kaplan-Meier survival analysis was used to calculate the probability of seizure freedom. In this patient group, abnormal lesion were detected by MRI in 70 out of 76 cases, and the ictal onset zone was finally identified within temporal lobe in 51 cases. The most favorable outcome, defined as Engel Class Ia, was observed in 26 (37%), 24 (40%), and 18 (41%) cases at 2, 5, and 10 years after surgery, respectively. The Kaplan-Meier survival curve in the overall group estimated the probability of seizure freedom as 75% (95% confidence interval [CI] 70–80%), 67% (62–72%), and 51% (45–57%) at 2, 5, and 10 years follow up, respectively. Half of all seizure recurrences occurred within the first 2 postoperative years. In this study, we showed that long-term favorable outcome of seizure control following resection surgery can be achieved in more than half of the patients.

In order to preserve postoperative language function, we recently proposed a new intraoperative method to monitor the integrity of the dorsal language pathway (arcuate fasciculus; AF) using cortico–cortical evoked potentials (CCEPs). Based on further investigations (20 patients, 21 CCEP investigations), including patients who were not suitable for awake surgery (five CCEP investigations) or those without preoperative neuroimaging data (eight CCEP investigations including four with untraceable tractography due to brain edema), we attempted to clarify the clinical impact of this new intraoperative method. We monitored the integrity of AF by stimulating the anterior perisylvian language area (AL) by recording CCEPs from the posterior perisylvian language area (PL) consecutively during both general anesthesia and awake condition. After tumor resection, single‐pulse electrical stimuli were also applied to the floor of the removal cavity to record subcortico‐cortical evoked potentials (SCEPs) at AL and PL in 12 patients (12 SCEP investigations). We demonstrated that (1) intraoperative dorsal language network monitoring was feasible even when patients were not suitable for awake surgery or without preoperative neuroimaging studies, (2) CCEP is a dynamic marker of functional connectivity or integrity of AF, and CCEP N1 amplitude could even become larger after reduction of brain edema, (3) a 50% CCEP N1 amplitude decline might be a cut‐off value to prevent permanent language dysfunction due to impairment of AF, (4) a correspondence (

Objective We describe temporal spread imaging (TSI) that can identify the spatiotemporal pattern of epileptic activity using Magnetoencephalography (MEG). Methods A three-dimensional grid of voxels covering the brain is created. The array-gain minimum-variance spatial filter is applied to an interictal spike to estimate the magnitude of the source and the time (Ta) when the magnitude exceeds a predefined threshold at each voxel. This calculation is performed through all spikes. Each voxel has the mean Ta ( ) and spike number (N sp ), which is the number of spikes whose source exceeds the threshold. Then, a random resampling method is used to determine the cutoff value of N sp for the statistically reproducible pattern of the activity. Finally, all the voxels where the source exceeds the threshold reproducibly shown on the MRI with a color scale representing . Results Four patients with intractable mesial temporal lobe epilepsy (MTLE) were analyzed. In three patients, the common pattern of the overlap between the propagation and the hypometabolism shown by fluorodeoxyglucose-positron emission tomography (FDG-PET) was identified. Conclusions TSI can visualize statistically reproducible patterns of the temporal and spatial spread of epileptic activity. Significance TSI can assess the statistical significance of the spatiotemporal pattern based on its reproducibility.

Cortico-cortical evoked potential (CCEP) has been widely used to probe brain network. Typically CCEP waveform consists of two negative potentials, N1 (peak: 10–50 ms) and N2 (peak: 100–500 ms). We, however, occasionally encounter atypical responses, such as those with prolonged N1 peak latency. We attempt to classify these atypical patterns and clarify their anatomical distribution. We retrospectively reviewed CCEP responses in two patients with intractable focal epilepsy, in whom CCEPs were obtained bystimulating all the implanted subdural electrodes (IRB#443). We classified CCEP into 6 groups based upon the N1 and N2 peak latencies; IA: N1 (10–50 ms), N2 (100–500 ms), IB: N1 (10–50 ms), N2: (50–100 ms), IIA: N1 (50–100 ms), N2: (100–500 ms), IIB: N1 (50–100 ms) without definite N2, III: mirror CCEP response with positive peaks, IV: N1 (100–500 ms) without definite N2. Atypical CCEP responses (IIA, IIB, III, IV) accounted for 16.0% among all the recording. They mostly distributed in the temporal lobe. There was a tendency of preferred locations for each pattern; IIB in the lateral temporal region and frontal operculum, III in the superior temporal gyrus and mesial temporal region, IV in the temporal pole. Further case accumulation is warranted to verify the results, which helps understand the significance of CCEP for presurgical evaluation.

There has been a paradigm shift in the understanding of brain function. The intrinsic architecture of neuronal connections forms a key component of the cortical organization in our brain. Many imaging studies, such as noninvasive magnetic resonance imaging (MRI) studies, have now enabled visualization of the white matter fiber tracts interconnecting the functional cortical areas in the living brain. Although such a structural connectome is essential for understanding of cortical function, the anatomical information alone is not sufficient. Practically, few techniques allow the investigation of the excitatory and inhibitory mechanisms of the cortex in vivo in humans. Several attempts have been made to track neuronal connectivity by applying direct electrical stimuli to the brain in order to stimulate subdural and/or depth electrodes and record responses from the functionally connected cortex. In vivo single-pulse electrical stimulation (SPES) and/or cortico-cortical evoked potential (CCEP) were recently introduced to track various brain networks. This article reviews the concepts, significance, methods, mechanisms, limitations, and clinical applications of CCEP in the analysis of these dynamic connections.

The preservation of language function during brain surgery still poses a challenge. No intraoperative methods have been established to monitor the language network reliably. We aimed to establish intraoperative language network monitoring by means of cortico‐cortical evoked potentials (CCEPs). Subjects were six patients with tumors located close to the arcuate fasciculus (AF) in the language‐dominant left hemisphere. Under general anesthesia, the anterior perisylvian language area (AL) was first defined by the CCEP connectivity patterns between the ventrolateral frontal and temporoparietal area, and also by presurgical neuroimaging findings. We then monitored the integrity of the language network by stimulating AL and by recording CCEPs from the posterior perisylvian language area (PL) consecutively during both general anesthesia and awake condition. High‐frequency electrical stimulation (ES) performed during awake craniotomy confirmed language function at AL in all six patients. Despite an amplitude decline (≤32%) in two patients, CCEP monitoring successfully prevented persistent language impairment. After tumor removal, single‐pulse ES was applied to the white matter tract beneath the floor of the removal cavity in five patients, in order to trace its connections into the language cortices. In three patients in whom high‐frequency ES of the white matter produced naming impairment, this “eloquent” subcortical site directly connected AL and PL, judging from the latencies and distributions of cortico‐ and subcortico‐cortical evoked potentials. In conclusion, this study provided the direct evidence that AL, PL, and AF constitute the dorsal language network. Intraoperative CCEP monitoring is clinically useful for evaluating the integrity of the language network. Hum Brain Mapp 35:4345–4361, 2014. © 2014 Wiley Periodicals, Inc.

It is now recommended that magnetic resonance imaging (MRI) or computed tomography (CT) be carried out in all patients with at least partial- and hopefully also generalized epilepsy to help identify intracranial lesions, such as hippocampal sclerosis, focal cortical dysplasia, brain tumor, cavernous malformation, and arteriovenous malformation. In order to identify epileptic focus, other neuroimaging tools, such as positron emission tomography (PET), single photon emission computed tomography (SPECT), and magnetoencephalography (MEG), are also useful, because an epileptogenic area is not necessarily located within these intracranial lesions. With regard to epilepsy surgery, neuroimaging is also required for the identification of functionally essential cortices, such as motor and language areas. MEG and functional MRI are noninvasively, and tractography with diffusion-weighted imaging (DWI) is also useful for visualizing relevant white matter tracts. Recently, it has been reported that the cortico-cortical network plays an important role in preservation of brain function. Thus, cortico-cortical evoked potentials (CCEP) and resting state fMRI are candidate methods to help clarify brain network. While good seizure control is an important treatment outcome for patients with intractable partial epilepsy, the preservation of brain function is equally important. For this reason, further development and clinical application of sophisticated imaging technique are required.

[Background and Purpose] Neuro-interventional radiology (NIVR) is increasingly recognized as an essential option for acute stroke treatment. However, the access to NIVR physician or NIVR-capable hospital is still limited. Patient transfer system between primary stroke centers (PSCs) and comprehensive stroke centers has a problem about deterioration during transfer, insufficient information transmission, small area coverage, and loss of time. We organized a mobile NIVR team consisting of 6-7 board certified NIVR physicians, and concluded a NIVR alliance program with affiliating PSCs. The team performed procedures at the local sites on request of PSCs. [Methods] Between 2008 and 2012, we concluded a NIVR alliance program with 7 affiliated PSCs. The team dispatched NIVR physicians to the PSCs immediately after receiving "rescue call." Clinical information including medical images was updated in real-time and interactive manner during travel. [Results] We received 23 calls and reacted to all cases. We treated 8 cases of acute ischemic stroke (6 mechanical thrombectomy, 3 carotid stenting, 5 for non-responder to intravenous rt-PA), and 15 for subarachnoid hemorrhage (14 aneurysm embolization, one parent artery occlusion). The mean travel distance was 39.0 km (min - max: 6.3 - 90.3). For acute ischemic stroke, the mean "door-to-puncture time" was 154 minutes (min - max: 130 - 168). For subarachnoid hemorrhage, procedure was performed on the onset or the next day. All the procedure were successfully performed and no deterioration related to procedure were observed. [Conclusions] The new application of NIVR delivery system can safely enable to avoid deterioration during transfer, cover larger area without delay, and enlarge the opportunity to access NIVR therapy for acute stroke patients.

In order to improve epileptic focus localization performance of non-invasive recording, we propose a new method to estimates and visualize the spatio-temporal spread pattern of the epileptic spike activities especially at the onset of spikes when the activity is too small for reliable source estimation. Result of this temporal spread imaging (TSI) method from the MEG data of five patients with intractable partial epilepsy in the course of presurgical evaluation were compared to the invasive focus localization with subdural grid recording. The TSI result were compatible with conventional equivalent current dipole estimation but indicated the epileptic focus better. This method will be a useful tool for non-invasive focus localization of epilepsy patients.

Postoperative courses in "coil-protruded" cases in embolization of unruptured cerebral aneurysms remain unknown. The purpose of this study is to investigate postoperative complications after coil protrusions.From May 2003 to December 2007, 90 consecutive cases with unruptured cerebral aneurysm treated by coil embolization were examined at National Cerebral and Cardiovascular Center. All patients received antiplatelet therapy prior to the procedure. The patterns of protrusions were classified into three; tail (T), loop (L), unraveled (U).Coil protrusions were observed in 17 cases (18.9%). Symptomatic ischemic complications occurred in 7 cases (7.8%). One case occurred in coil protrusions (group P) and 6 cases occurred in no coil protrusions (group N). Infarctions on MR diffusion-weighted image within 7 days after embolization were found in 10 cases (58.8%) in group P and in 28 cases (38.4%) in group N. Infarction on MR fluid attenuated inversion recovery 7 days or later were found in 0 in group P, and in 4 (5.5%) in group N. There were no significant differences. The number of each protrusion pattern was as follows: T was 12 cases, L was 3 cases and U was 2 cases. Symptomatic ischemia was observed in one case (8.3%) in T. Infarctions on MR diffusion-weighted image within 7 days after embolization were found in 7 (58.3%), 1 (33.3%) and 2 (100%), respectively. There were no significant differences between the three morphological patterns.In this retrospective study, coil protrusion after embolization of unruptured cerebral aneurysms on antiplatelet therapy, did not increase the incidence of ischemic complications.

Objective: In order to establish a new intraoperative monitoring for preservation of subcortical language pathways, we applied technique of cortico-cortical evoked potentials (CCEP) during brain surgery. Methods: Subjects were 17 patients with brain tumors located close to the arcuate fasciculus (AF) in the language-dominant left hemisphere. Af- ter craniotomy, electrodes were placed over frontal and parieto-temporal perisylvian areas. Single-pulse stimuli were applied to several pairs of electrodes in the frontal area to record CCEP from the parieto-temporal area. Under general anesthesia, the anterior perisylvian language area (AL) was first defined by CCEP connectivity patterns, and also by presurgical neuroimaging findings. We then monitored the integrity of the language network by stimulating AL and recording CCEPs from the posterior peri- sylvian language area (PL) consecutively during both general anesthesia and awake condition. In the awake condition, language assessment with batteries was also sequentially performed throughout surgical procedures. To confirm language function in AL, high-frequency electrical stimulation (ES) was performed during awake craniotomy in nine patients, who had neither cognitive impairment nor aphasia preoperatively. Results: In all, the CCEP connectivity pattern delineated perisylvian lan- guage network between AL and PL even under general anesthesia. CCEP amplitude declined in two patients (≤32%) during surgical procedures. Two patients had transient language impairment postoperatively. One patient who showed 32% decrease of CCEP amplitude presented phonemic para- phasia during and after operation. Another patient who did not showed decrease of CCEP amplitude developed language impairment immediately after surgery because of brain edema. Language function recovered within a few months in both patients. In all, CCEP monitoring successfully prevented persistent language impairment. In all nine patients who were awakened fully, high-frequency ES confirmed language impairment at AL. Conclusions: Although further accumulated cases will be warranted for establishing the sensitivity and specificity, intraoperative CCEP delineated the perisylvian or dorsal language network and would be useful for online monitoring of subcortical language pathways.

Background: Carotid artery occlusion can lead to the development of rare true posterior communicating artery (PCoA) aneurysms because of hemodynamic stress on the PCoA. Surgical treatment of these lesions is challenging. Case Description: The authors report a case of a true PCoA aneurysm that developed and ruptured 37 years after ligation of the ipsilateral common carotid artery for epistaxis. The lesion was successfully treated with clipping of the distal M1 segment of the middle cerebral artery (MCA) after the occipital artery-radial artery free graft-MCA bypass, which led to extreme reduction in collateral flow through the PCoA. A cortical branch, located just proximal to the obliteration site, functioned as a sufficient flow outlet. The aneurysm shrank, and the patient has been doing well without any symptoms for 5 years after surgery. Conclusions: M1 obliteration combined with high-flow extra-intracranial bypass might be a promising option for a true PCoA aneurysm, and therapeutic design that leaves a sufficient flow outlet on the M1 is mandatory to avoid unexpected occlusion of the M1 and its perforators.